Bio/Biochem Flashcards

Question 1

Q

Acronym for purines and pyrimidines

Answer

A

CUT the PY/ Pure As Gold
(Cytosine, Uracil, Thymine are pyrimidines (ONE RING); Adenine and Guanine are Purines (TWO RINGS))

Question 2

Q

Western Blots

Answer

A

Use antibodies as probes to detect proteins, which bind at the epitope

Question 3

Q

Phosphorylation

Answer

A

Occurs where OH group of an amino acid side chain acts as a nucleophile and attacks a phosphate group on ATP (Serine, threonine, tyrosine most common)

Question 4

Q

Transcription factors

Answer

A

Proteins that bind to DNA sequences to regulate transcription (RNA synthesis); impact RNA polymerase binding

are translated in the cytoplasm but act in the nucleus to control gene expression.

Question 5

Q

Catabolic

Answer

A

Break down carbs fats prots –> CO2, H2O, NH3
Produce ATP
Hormones involved: glucagon, epinephrine, cortisol

Question 6

Q

Anabolic

Answer

A

Build up amino acids, sugar, fatty acids, nitrogenous bases –> proteins, polysaccharides, lipids, nucleic acids
Consume ATP
Hormones involved: insulin, growth hormone, testosterone, estrogen

Question 7

Q

Glycolysis

Answer

A

Glucose –> pyruvate
Generates ATP and NADH

glucose –> G6P –> F6P –> F1,6BP–> G3P –> 1,3-Bpg –> 3 pg –> 2 pg –> PEP –> pyruvate

Opposite reaction: gluconeogenesis (pyruvate –> glucose)

Question 8

Q

glycogen synthase

Answer

A

rate limiting enzyme of glycogen synthesis

stimulated by G6P and insulin

inhibited by epinephrine and glucagon

Question 9

Q

Glycogenesis

Answer

A

1st you use Glycogen synthase to create alpha-1,4 (create chain)

2nd you use Branching enzyme to create alpha-1,6 (create branch)

glycogen synthase extends both branches

glucose –> glycogen

Question 10

Q

Glycogenolysis

Answer

A

Glycogen –> glucose
1st you use Glycogen phosphorylase to break alpha-1,4
(remove from chain to create new chain)

2nd you use Debranching enzyme which breaks the alpha-1,6 (one catalytic site) and forms a new alpha-1,4 bond in the chain (second catalytic site)
(remove from branch to add to existing chain- see above)

glycogen –> G1P –> G6P –> Glucose

Opposite reaction: glycogenesis (glucose –> glycogen)

Question 11

Q

Fatty acid oxidation
(What is made? Are coenzymes oxidized or reduced?)

Answer

A

fatty acid –> acetyl CoA

Reduced – causes FAD2+ –> FADH2 and NAD+ –> NADH

Opposite reaction: fatty acid synthesis (acetyl CoA –> fatty acids)

Question 12

Q

Beta Oxidation

Answer

A

Generates acetyl CoA to enter CAC
Shuffles into mitochondria by carnitine transferase
1. oxidation (FADH2)
2. hydration
3. oxidation (NADH)
4. thiolysis

Question 13

Q

Glucagon

Answer

A

Released in response to low blood glucose
Released by pancreas
Stimulates fatty acid oxidation to provide energy
Stimulates release of phosphorylated glucose residues from liver glycogen (which is broken down during glycogenolysis to provide glucose)

Question 14

Q

Low Blood Glucose

Answer

A

Hypothalamus sends nerve impulses to adrenal medulla which secretes epinephrine, glucagon released by alpha cells of pancreas, liver releases glucose in response to glucagon and epinephrine

Question 15

Q

High Blood Glucose

Answer

A

Beta cells secrete insulin which promotes glucose absorption in the blood

Question 16

Q

NADPH produced during

Answer

A

PPP and fatty acid biosynthesis

Question 17

Q

Primary structure stabilized by

Answer

A

Covalent peptide bonds

Question 18

Q

Secondary structure stabilized by

Answer

A

hydrogen bonds between amide and carbonyl hydrogens
- backbone

Question 19

Q

Tertiary structure stabilized by

Answer

A

hydrophobic interactions and stabilized by H bonds, electrostatic interactions
(noncovalent interactions between side chains)
- 3D structure

Question 20

Q

Quaternary structure stabilized by

Answer

A

stabilized by hydrophobic interactions
- multiple polypeptides joined

Question 21

Q

Mechanically gated ion channels respond to

Answer

A

pressure/ tension

Question 22

Q

Voltage gated ion channels respond to

Answer

A

changes in membrane potential caused by other channels

Question 23

Q

Liquid chromatography

Answer

A

Separates and Quantifies small molecules (amino acids/dipeptides)
Molecules enter column packed with either hydrophobic or hydrophilic beads– different compounds have different strength of activation (stronger attraction will stay in column longer)

Question 24

Q

Gel Electrophoresis

Answer

A

Used for large molecules (proteins)

Question 25

Q

Krebs Cycle Products

Answer

A

Releases NADH, FADH2, GTP

reduces NAD+ to NADH

Question 26

Q

Pyruvate Dehydrogenase Complex

Answer

A

CONVERTS PYRUVATE INTO ACETYL COA! also CO2 and NADH
this is the link between glycolysis and the CAC

activated by insulin in the liver; not responsive to nervous system hormones

one of three fates for pyruvate; other two: conversion to lactate by lactate dehydrogenase or conversion to oxaloacetate by pyruvate carboxylase

another definition: catalyzes the decarboxylation reaction that converts pyruvate to acetyl-CoA. This reaction requires CoA, thiamine pyrophosphate, lipoic acid, and NAD+ and links glycolysis to the citric acid cycle. These pathways are essential for maximal ATP synthesis.

Question 27

Q

Lipoic acid

Answer

A

the cofactor of PDH complex that facilitates the transfer of electrons from NAD+ to NADH

Question 28

Q

Agonists

Answer

A

Drugs/substances that bind to a receptor inside a cell/ on cell surface and create the same action as the substance the typically binds the receptor

Question 29

Q

Schiff Bases

Answer

A

formed between a protein and substrate by a primary amine (eg. Lysine side chain)

Question 30

Q

G Protein Activation

Answer

A

requires exchange of GDP for GTP

cAMP is known to be produced during G protein-coupled receptor-triggered signaling.

Question 31

Q

Titration Curves (flat part? Sloped part?)

Answer

A

Flat part indicates pka
Sloped part indicates where group is deprotonated

Question 32

Q

pKa C terminis

Question 33

Q

pKa N terminis

Question 34

Q

Buffering region of titration curve

Answer

A

region near pKa that is relatively flat due to addition of a base that only slightly changes pH

Question 35

Q

Transverse Tubules

Answer

A

where action potentials propagate in muscle tissue

Question 36

Q

Sarcolemma

Answer

A

plasma membrane of muscular fiber

Question 37

Q

Ubiquinone (ox or reduced)

Answer

A

oxidized in the ETC

Question 38

Q

Common oxidoreductases

Answer

A

NADH, NADPH, FADH2

Question 39

Q

Ping pong mechanism

Answer

A

a substrate binds enzyme and reacts, then leaves the active site and a second substrate comes and reverts it to its original form

(no ternary complex is formed)

Question 40

Q

Ternary complex

Answer

A

formed in enzymatic reactions when a three membered complex forms

Question 41

Q

Hill coefficient

Answer

A

level of cooperativity for an enzyme
greater than 1 is cooperativity, less than 1 is negative cooperativity and exactly 1 is no cooperativity.

Question 42

Q

Catalytic efficiency

Question 43

Q

Krebs Cycle (activated/inactivated)

Answer

A

Activated by ADP (indicate energy is needed) and Ca2+ (allosterically activate Krebs)
Inhibited by those that indicate sufficient energy (ATP, citrate, succinyl CoA, NADH)

Question 44

Q

Reducing Sugars

Answer

A

contain a free anomeric carbon that can be oxidized/act as a reducing agent (not in a glycosidic bond)
linear form: either aldehyde/ketone
cyclic form: hemiacetal/hemiketal at anomeric carbon

Question 45

Q

Nonreducing Sugars

Answer

A

have acetal/ketal groups does not have free aldehyde or ketone

a carbohydrate that is not oxidized by a weak oxidizing agent

ex. sucrose

Question 46

Q

Glycosidic Bonds

Answer

A

Linkage of nucleophilic functional group to anomeric C of sugar

Question 47

Q

Amino acids with alkyl side chain

Question 48

Q

Anomeric carbon

Answer

A

A carbon that has two bonds to oxygen

Question 49

Q

Triglycerides

Answer

A

Energy storage lipids
Catabolized to produce ATP
Composed of 3 fatty acids and one glycerol

Question 50

Q

Sphingolipids

Answer

A

Membrane Lipids

organized into ceramide, sphingomyelins, cerebrosides, and gangliosides

Question 51

Q

Prostaglandins

Answer

A

Signaling Lipids

Derived from arachidonic acid; regulate cAMP

Question 52

Q

Cholesterol structure

Answer

A

Hydroxyl group attached to four fused rings

Question 53

Q

Cytosine

Answer

A

becomes deaminated to form Uracil (carbonyl at top)

Question 54

Q

Fatty acid transport
from where to where?
what activates?
ATP required?

Answer

A

From cytosol to mitochondria requires fatty acid to be activated with CoA then carnitine
Requires ATP

Question 55

Q

Eukaryotic cells

Answer

A

Include protazoa and fungi

Question 56

Q

Origin of Replication

Answer

A

Prokaryotes have a single origin of replication
Eukaryotes have multiple origins of replication

Question 57

Q

Pyruvate

Answer

A

Present in cytoplasm of both prok and euk

Question 58

Q

zymogens

Answer

A

enzymes that must be cleaved to become activated

enzyme precursors

Question 59

Q

apoenzymes

Answer

A

inactive enzymes that are not bound to a cofactor

Question 60

Q

holoenzymes

Answer

A

active enzymes that are bound to a cofactor

Question 61

Q

Steroid hormones

Answer

A

derived from cholesterol (cholesterol synthesized from isoprene –> monoterpene –> squalane (triterpene)
not soluble in water or blood, need protein transport in the bloodstream but can diffuse through membrane with transport proteins

Question 62

Q

Amphipathic helices

Answer

A

have hydrophobic residues every 3/4 residues

Question 63

Q

Strong Binding Affinity

Answer

A

large Kbinding
Small Kunbinding
Small Kd

Question 64

Q

DNA polymerase

Answer

A

copies genetic code onto new dna strand from template strand!

Extends primers, synthesizes DNA (uses original strand as a template and duplicates it) , proofreads DNA
Acts in 5’ to 3’ direction

work in groups to create two identical DNA duplexes from a single original DNA duplex

(Reads template strand in 3’ to 5’ direction while synthesizing in 5’ to 3’)

Answer 61

A

Act in 3’ to 5’ direction
Remove incorrectly paired nucleotides

Answer 62

A

Large molecules elute faster
Small molecules elute slower

Answer 63

A

Bone
Blood
Fat
Tendons/Ligaments
Cartilage

Answer 64

A

Skin
Lining of Organs

Answer 65

A

Skeletal
Cardiac
Smooth

Answer 66

A

Phosphofructokinase

Answer 67

A

Fructose- 1,6- biphosphate

Answer 68

A

isocitrate dehydrogenase

Answer 69

A

glycogen synthase

Answer 70

A

glycogen phosphorylase

Answer 71

A

acetyl CoA carboxylase

Answer 72

A

carnitine acyltransferase 1

Answer 73

A

carbamoyl phosphate synthase 1

Answer 74

A

HMG-CoA synthase

Answer 75

A

HMG-CoA reductase

Answer 76

A

form covalent bonds with enzymes

Answer 77

A

form non-covalent bonds with target enzymes

Answer 78

A

form from oxidation of cysteine bonds

Answer 79

A

Often rich in cholesterol and poor in phospholipids

Answer 80

A

L - except glycine

Answer 81

A

Cerebral cortex
Spinal Cord
Efferent neurons
Skeletal muscle cells

Answer 82

A

central to outside

Answer 83

A

external to central

Answer 84

A

requires release of calcium
depolarization: Na+ from voltage gated Ca 2+ channels open causing Na+ channels to open- increase membrane potential + likely to fire action potential
Repolarization: K+ efflux (flow out of voltage gated potassium channels)
Hyperpolarization: when membrane potential dips below resting state- neurons unlikely to fire

Answer 85

A

growth (creating organelles + increasing in size)

Answer 86

A

DNA synthesis
Cell’s genetic info is replicated– each chromosome will have 2 chromatids bound together at centromere

Answer 87

A

growth and mitosis prep (checkpoints)

Answer 88

A

added to the first nucleotide in the transcript during transcription.
A modified guanine (G) nucleotide, it protects the transcript from being broken down.
Helps the ribosome attach to the mRNA and start reading it to make a protein.
Only present in Eukaryotes

Answer 89

A

Adding subunits/ nucleotides to form a single stranded RNA

Answer 90

A

process of binding complementary nucleotides due to base pairing of complementary regions

Answer 91

A

Increases proton conc of solution

Answer 92

A

Increase in hydroxide conc of solution

Answer 93

A

acids increase proton concentration and are H+ donors

Answer 94

A

Any species that is an H+ Acceptor

Answer 95

A

electron acceptors

Answer 96

A

electron donors

Answer 97

A

created when a proton is lost by an acid

Answer 98

A

created when a proton is accepted by a base

Answer 99

A

are stable

Answer 100

A

when electronegative atom pulls some of charge towards itself; stronger when electronegative atoms are in a closer proximity
stabilizes and creates stronger acids

Answer 101

A

stabilizes and creates stronger acids

Answer 102

A

Strong acid, likely to dissociate

Answer 103

A

strong acid

Answer 104

A

the pH where above it, an atom will lose protons, below it will keep protons

Answer 105

A

deprotonated

Answer 106

A

protonated

Answer 107

A

Granulocytes; contain membrane bound nucleus with DNA

Answer 108

A

constrict pupils
constrict bronchidea

rest and digest AND urination

deals with decreased blood pressure

Answer 109

A

dilate pupils
relax bronchi

Answer 110

A

Carry electrical signals to the CNS

Answer 111

A

carry signals from CNS to outer parts

Answer 112

A

Released from adrenal cortex in response to low BP

stimulates the collecting duct to reabsorb Na+ and secrete K+ into the urine. This reabsorption of Na+ increases the osmolarity of the renal interstitial fluid, which promotes water reabsorption.

Answer 113

A

method for sterilization

Answer 114

A

considered “cyclical”
separates sister chromatids to create 2 diploid daughter cells

Answer 115

A

considered “non-cyclical”
separates homologous chromosomes to create daughter haploid cells

Answer 116

A

highly reactive oxidizing agents

Answer 117

A

evolved independently to carry out the same function

Answer 118

A

have similar evolutionary history and serve different functions

Answer 119

A

absorb fat into lymphatic system

Answer 120

A

centromere is located at the end rather than at the center
humans have 5 pairs

Answer 121

A

When increased, transcription increased, and chromatin/gene expression will be active

decreases positive charge of lysine and weakens interaction of histone with DNA

open chromatin conformation

Answer 122

A

no transcription will occur, chromatin/gene expression will be depressed

closed chromatin conformation

Answer 123

A

can be made in a variety of locations (ER/cytoplasm)

Answer 124

A

will take place in the nucleus

Answer 125

A

Will be consistent among species from various kingdoms

takes place in nucleus and mitochondria

Answer 126

A

Mirror images, differ at every carbon

Answer 127

A

Convert between isomers by the rotation of a single bond

Answer 128

A

type of diastereomer- sugars that vary at only one stereocenter

Answer 129

A

mediate perceptions of pain

Answer 130

A

Derived from arachidonic acid
Include prostaglandins, thromboxanes, leukotrienes

Answer 131

A

Amino acid derived hormones (derived from tyrosine)
Include epinephrine, norepinephrine, dopamine

Answer 132

A

Lack introns and code for proteins or RNA

Answer 133

A

Located between cytoplasm of adjacent cells

Allow rhythmic depolarization and contraction

Allow cell-cell communication, also called connexons

Answer 134

A

silence genes by interrupting gene expression

Answer 135

A

may result in glucose/ketone bodies in urine

Answer 136

A

may result in presence of protein in urine

Answer 137

A

Km increases, Vmax same

Answer 138

A

Km decreases, Vmax decreases

Answer 139

A

KM may increase or decrease depending on whether affinity is increased or decreased, Vmax decreases

Answer 140

A

Km same, Vmax decreases

Answer 141

A

Has nitrogenous base and 5C sugar

Answer 142

A

Has nitrogenous base, 5C sugar, and P group

Answer 143

A

large and polar, move freely through bloodstream but cannot pass through membrane
ex.
FLAT PEG,
ADH, Oxytocin
PTH
Gulcagon, Insulin
Calcitonin

Answer 144

A

nonpolar, not soluble, can directly diffuse into membrane but not bloodstream
ex. cortisol, aldosterone, testosterone, progesterone, estrogen

Answer 145

A

The final major process of aerobic respiration

The majority of aerobically-derived ATP is synthesized

This process begins by passing electrons through the electron transport chain (ETC), to a final electron acceptor, oxygen.

This is the only time in eukaryotic aerobic respiration where oxygen is directly required.

NADH and FADH2 are oxidized to create NAD and FAD.
ADP becomes ATP and H2O is produced

These reactions take place in specialized proteins where NADH and FADH2 are used up, molecular oxygen is reduced into water, and approximately 30-36 ATP are created

energy is harnessed through electron transport chain and ATP synthase to create ATP.

Answer 146

A

Uses free oxygen as the final electron acceptor of the electrons removed from NADH and FADH2 formed in glycolysis and the Krebs cycle
Complexes I-IV embedded in the inner mitochondrial membrane and two small electron carriers shuttling electrons between them.
Energy released from electron transfers used to pump H+ across membrane. The unequal concentrations of H+ ions = electrochemical gradient, leading to chemiosmosis (the passive diffusion of the protons down their concentration gradient) which is coupled to ATP synthase
This proton movement generates 90% of the ATP synthesized during oxidative phosphorylation. The electrons passing through the electron transport chain lose energy until eventually they are donated to O2, which accepts two H+ ions and is transformed into water.

NADH to NAD+

Answer 147

A

NADH dehydrogenase

Answer 148

A

Succinate dehydrogenase

Answer 149

A

Cytochrome C

Answer 150

A

cytochrome c oxidase

Answer 151

A

Mineralocorticoid

Increases sodium absorption in distal convoluted tubule and collecting duct and therefore water reabsorption in blood

Decreases Urine output

Increases excretion of potassium (K) and hydrogen ions in the urine

Answer 152

A

Peptide hormone, also known as vasopressin.
INCREASING WATER REABSORPTION (increase permeability of distal tubules and collecting ducts).
Causes excretion of more concentrated urine
Acts to DECREASE OSMOLARITY of blood by increasing the amount of water present without changing the solute levels.
Increase blood volume and pressure

Answer 153

A

Used by endocrine system to deal with excess blood volume

Aids in loss of salt within the nephron and acts as a diuretic

Answer 154

A

allows proteins to be separated by mass alone.
More complex than gel electrophoresis (effective for DNA/RNA which are negatively charged)
Proteins can have positive, negative, or neutral charges, and these charges may not be uniformly distributed throughout the molecule.

Uses a strong anionic detergent: sodium dodecyl sulfate. The “sulfate” portion of this name denotes the negatively-charged head, while the “dodecyl” refers to a long hydrocarbon chain that forms the molecule’s tail.
Denatures native proteins into their unfolded polypeptide states to prevent protein shape from impacting the separation.

SDS coats proteins with even distribution of charge per unit mass + when highly anionic SDS associates with polypeptide backbone, charge of polypeptide becomes negligible in comparison to imposed charges of SDS– now they will all travel towards POSITIVE END

The larger the protein, the more hindered it is as it moves down the gel. Smaller proteins can travel through the pores of the gel more easily + migrate farther toward the positive pole.

If a heterodimer is sent through an SDS page, add up the two bands to get the accurate kDa

Answer 155

A

the transfer of active humoral immunity in the form of ready-made antibodies, from one individual to another

Answer 156

A

an immune response that does not involve antibodies, but rather involves the activation of PHAGOCYTES, antigen-specific lymphocytes, and the release of various cytokines in response to an antigen

Answer 157

A

the hormone responsible for stimulating the mammary glands to produce milk

Answer 158

A

a hormone produced by gonadotropic cells in the anterior pituitary gland.
In females, rise of LH triggers ovulation and development of the corpus luteum.
In males, LH stimulates Leydig cells to produce testosterone.

Answer 159

A

Activated by parathyroid hormone; promotes bone resorption (breaking down bone)

Answer 160

A

antagonistic to calcitonin- raises blood calcium levels
decreasing bone formation by osteoblasts and increasing bone degradation by osteoclasts (bone resorption to break down tissue)

Answer 161

A

a thyroid hormone responsible for lowering blood calcium concentrations.

limits blood calcium concentration by limiting calcium loss from bone

stimulates bone formation by increasing osteoblast activity and decreasing osteoclast activity

Answer 162

A

a hormone secreted by the medulla of the adrenal glands
redirection of bodily blood flow, increased heart rate, dilation of bronchioles, and the release of sweat on the skin surface.

Answer 163

A

a 2 electron carrier

Answer 164

A

The process of carrying lactate from cells undergoing anaerobic metabolism to the liver where it provides glucose and moves regenerated glucose from the liver back to cells (muscles)

Connects gluconeogenesis and glycolysis

Answer 165

A

Gel electrophoresis in the absence of any denaturants– the protein will maintain its structure

Useful to compare molecular size or charge of proteins known to be similar

Answer 166

A

both precise and accurate

Answer 167

A

give you the same results multiple times

Answer 168

A

isolate molecules that bind a particular ligand

Answer 169

A

lower activation energy but do not change deltaG

Answer 170

A

Will often be denoted by a sigmoidal curve

Answer 171

A

Secretes amino acid based hormones (norepinephrine/epinephrine)

Is innervated by the sympathetic nervous system

Answer 172

A

Secretes steroid based hormones (glucocorticoids for glucose levels and protein metabolism/mineralocorticoids for salt and water homeostasis)

Answer 173

A

Secreted from the adrenal cortex
Stimulates Na+ reabsorption in the kidneys, leading to increased water retention due to osmosis
Increased water retention increases blood volume and blood pressure

Answer 174

A

Secreted from the adrenal medulla
Mobilize body under stress and promote rapid information processing by maximizing blood flow to organs.
Regulate blood flow by:
Vasoconstriction
+
Vasodilation

Answer 175

A

Narrowing of blood vessels supplying the intestines, kidney, and other abdominal organs decreases blood flow to these organs and conserves oxygen/nutrients for other tissues.
Warms the body by reducing heat loss

Answer 176

A

Widening of blood vessels leading to the heart and skeletal muscles increases oxygen/nutrient delivery to these organs.
Cools the body

Answer 177

A

regulate blood pressure and respond to stress

Answer 178

A

NADH, FADH2, Acetyl Co-A

Answer 179

A

will flow more easily with a decreased electric resistance

Answer 180

A

organelle that breaks down long chain fatty acids

Answer 181

A

Made up of solid rods of actin; provide protection for cell; participate in cytokinesis

found in cytoplasm and muscles

Answer 182

A

filamentous proteins including keratin, desmin, vimentin, and lamins
Involved in cell-cell adhesion/maintain cytoskeleton

Answer 183

A

start translation with methionine, contain similar RNA polymerase, and associate DNA with histones

Answer 184

A

Sugars and amino acids

Answer 185

A

Carried by retroviruses
Synthesizes DNA from a single stranded RNA

Answer 186

A

phages replicate rapidly and release progeny via lysis of host cell

Answer 187

A

phages integrate genome with the host cell and replicate as the cell divides

the virus is dormant and its DNA is integrated with that of the host’s genome. All of the daughter cells from the initial infected cell will carry the virus’s genetic information. At some point, the virus will be triggered and will hijack the cellular machinery in order to produce viral progeny. (will then enter lytic phase)

Answer 188

A

most cells are arrested in this phase

Answer 189

A

Condensation of chromatin into chromosomes
Centriole pairs move towards opposite ends
Spindle Fibers form
Nuclear membrane dissolves and genetic info exposed
Kinetochore are the attachment points for fibers of spindle apparatus– appear at centrosome

Answer 190

A

Centriole pairs at opposite ends
Kinetochore fibers align chromosomes at metaphase plate

Answer 191

A

Centromeres split, allowing sister chromatids to separate towards opposite poles
Nondisjunction in this phase may result in wrong number of chromosomes

Answer 192

A

Spindle apparatus (microtubules) disappears, nuclear membrane reforms, chromosomes uncoil into chromatin

Answer 193

A

major distinction between mitosis and meiosis; where homologous chromosomes come together and intertwine

the pairing of homologous chromosomes during prophase I of meiosis.

Answer 194

A

Secreted in response to FSH
Development and maintenance of female reproductive system

Answer 195

A

Secreted by corpus luteum (then placenta), controlled by LH
Involved in development and maintenance of endometrium; prepares uterus for implantation of fertilized ovum

Answer 196

A

outermost layer
generates integument, epithelia of nose/mouth/anus, lens of eye, nervous system

Answer 197

A

develops into musculoskeletal, circulatory, excretory,
gives connective tissue layers to digestive and respiratory systems and adrenal cortex
give rise to gonads

Answer 198

A

Innermost layer of cells
Make up lining of digestive and respiratory tracts
pancreas, thyroid, bladder, and distal urinary tract and liver are derived from this tissue

Answer 199

A

biological aging, eventually results in cell dealth

Answer 200

A

Oligodendrocytes in the CNS and Schwann cells in the PNS

Answer 201

A

Support and myelinate neurons
include:
Schwann cells to wrap the axons of some neurons with myelin

Satellite cells to provide structural support and supply nutrients to neuron cell bodies in sensory, sympathetic, and parasympathetic ganglia (groups of cell bodies); similar to astrocytes in the CNS

Answer 202

A

nourish neurons and form blood-brain barrier (control transmission of solutes from bloodstream into nervous tissue)

make extensive contact with blood vessels and regulate blood flow; maintain homeostasis

Answer 203

A

Line ventricles of brain and produce cerebrospinal fluid (supports brain/acts as shock absorber)

Answer 204

A

Phagocytic cells that ingest and break down waste and pathogens

Answer 205

A

Influx of Na+
Causes excitatory signals to increase membrane potential, neurons become more likely to fire action potential
Voltage gated Ca 2+ channels open up, causing exocytosis of neurotransmitters which open up Na+ channels and trigger action potential

Answer 206

A

Efflux of K+
Cell membrane potential decreases
K+ cations are driven out of cell, negative membrane potential will be restored

Answer 207

A

Has to do with length and cross-sectional area
More length= more resistance, slower conduction
More cross-sectional area= faster propagation, decreased resistance

Answer 208

A

Brain and Spinal Cord

Answer 209

A

Motor Neurons (to muscles and glands) and sensory neurons
Motor neurons include Somatic and Autonomic Nervous System (includes Sympathetic and Parasympathetic division)

Answer 210

A

main nerve of parasympathetic nervous system
inhibition of this nerve causes increased cardiac output

Answer 211

A

Require an intermediary to act

Endocrine cells to rest of body

Answer 212

A

Bridge between nervous and endocrine system
Controls homeostasis and hormones
Regulated by negative feedback
Hypophyseal portal system connects hypothalamus to anterior pituitary

Answer 213

A

Causes increase in volume of thoracic cavity
Causes decrease in the inter pleural pressure between thoracic wall and lung

Answer 214

A

Nares, pharynx, larynx, trachea, bronchi, bronichiles, alveoli

Answer 215

A

When the error is at either end of the DNA strand, the DNA backbone is cleaved by exonucleases, Endonucleases repair DNA in middle of strand
After damaged base is removed, DNA polymerase corrects base to pair with the opposite strand, and a ligase enzyme catalyzes formation of new phosphodiester bonds.

Answer 216

A

linked to nitrogen bases at the 1′ carbon of the sugar. The 3′ and 5′ carbons are linked to phosphate groups, which each link to the rest of the DNA backbone.

Answer 217

A

occurs from different mating behaviors

Answer 218

A

F1 and offspring are viable and fertile, but F2 is sterile

Answer 219

A

Binding of Ca2+ causes troponin to shift the position of tropomyosin on the actin filament so it is no longer blocked and myosin can bind and allow force production

Answer 220

A

slow-twitch fibers have the slowest contractile velocity but are rich in mitochondria and capillaries. These fibers are fatigue resistant and are the most recruited fibers

Answer 221

A

(fast-twitch, oxidative-glycolytic) fibers contract several times faster than type I fibers but have similar mitochondrial density to type I fibers (mitochondria rich). Also fatigue resistant

Answer 222

A

fast-twitch, glycolytic fibers, contract faster, typically have lower mitochondrial density than type I or IIa fibers.
More reliant upon anaerobic metabolism (ie, glycolysis, fermentation) than are type I and IIa fibers, which are more reliant on aerobic respiration.

Answer 223

A

Found in skeletal muscle fibers
Store Ca2+ so that they are not present in the cytosol to activate processes

Answer 224

A

epidermis layer composed of dead skin cells; layer helps repel water

Answer 225

A

epidermis layer found on palms of hands and soles of feet

Answer 226

A

epidermis layer where keratin production occurs

Answer 227

A

epidermis layer that gives skin strength and flexibility

Answer 228

A

where keratinocytes are formed before moving up to the epidermis and being shed; also contains melanocytes

Answer 229

A

epidermis layerwhere keratinocytes are formed before moving up to the epidermis and being shed; also contains melanocytes

Answer 230

A

has 5 strata; It is composed of epithelial tissue and is continuously sloughed off (superficial layer) and reproduced (deep layer). Merkel cells, Langerhans cells, melanocytes, and keratinocytes are all cell types in the epidermis.

Answer 231

A

composed of a matrix of connective tissue embedding several cell types

contains blood vessels to nourish skin with oxygen and nutrients; nerves; glands; hair follicles; collagen

contribute to strength and flexibility

Answer 232

A

contains blood vessels/nerves AND a layer of fat which maintains body temp

“shock absorber”

Answer 233

A

pathway containing linked activities of hypothalamus, pituitary gland, and thyroid glands

Answer 234

A

The role is to maintain an adequate calcium concentration in the blood
Stimulates three processes:
1) intestinal absorption of calcium from the diet,
2) reabsorption of calcium filtered by the kidney (ie, reducing urinary calcium loss),
3) promoting release of bone calcium into the blood.

Answer 235

A

Overstimulated bone resorption and reduced bone density

Answer 236

A

the most active form of vitamin D and stimulates intestinal calcium absorption

Answer 237

A

In the renal cortex, blood is first filtered through glomerular capillaries into the Bowman’s capsule (a cup-shaped structure) of each nephron. The filtered fluid (filtrate) then flows through the tubular segments of the nephron. The proximal tubule is the first segment the filtrate traverses. Next, the filtrate flows into the loop of Henle, a two-limbed structure stretching into the medulla that reabsorbs water and salt (NaCl) from the filtrate into the body via countercurrent multiplication:

Filtrate flows through the descending limb of the loop, which is highly permeable to water but impermeable to NaCl. Water will move from areas of low solute concentration to areas of high solute concentration. Accordingly, because salt concentration in the medulla is high, water is passively reabsorbed (via osmosis) from the filtrate flowing through the descending limb into the salty medulla, where it is taken up by blood vessels.

Filtrate then flows into the ascending limb, which is highly permeable to NaCl but impermeable to water. Initially, NaCl is passively reabsorbed into the medulla as filtrate moves up the ascending limb. However, as the ascending limb nears the cortex, NaCl is actively transported from the filtrate into the medulla, preserving the medulla’s high salt concentration. Because water follows NaCl, the saltiness of the medulla promotes continued water reabsorption from the descending loop of Henle and the collecting duct.

Answer 238

A

most frequent to least frequent, is cecum, ascending colon, transverse colon, descending colon, sigmoid colon

Answer 239

A

Decreases when large amounts of water are consumed; higher concentration of solutes will be reabsorbed and more water excreted by the kidneys (more dilute urine)

Answer 240

A

blood enters via renal arteries which branch into smaller arterioles that branch into glomerulus (filtration occurs)

Glomerular capillaries have large pores that blood passes through as it is filtered based on particle size

Water, solutes, and small proteins can pass through

The filtrate is collected by the Bowman’s capsule and is delivered to the proximal convoluted tubule (PCT), the next section of the nephron.

Answer 241

A

thin protein filaments made of actin, are involved in cytokinesis and determining cellular shape.
Also responsible for cellular movement, muscle contractions, and movement of vesicles within cells.

Answer 242

A

made of protein subunits (ie, keratin, lamins, vimentin, and desmin).
Involved in determining the shape of the cell and make up the nuclear lamina;
Help anchor organelles to specific areas of the cell.

Answer 243

A

a protein that can function as a motor protein
Interacts with actin (not tubulin) during muscle contraction.

Answer 244

A

made of alternating α- and β-tubulin subunits, which assemble into hollow tubes.
Involved in cell movement
Involved in cell motility, forming the core of cilia and flagella, and the formation of the mitotic spindle during cell division

Answer 245

A

detection of depolarization by t-tubules
Ca2+ is released from SR through channel
Rise in cytosolic Ca2+ leads to binding of Ca2+ to troponin which enables stronger binding

Answer 246

A

Mediates between
H2O + CO2 and H2CO3 in bicarbonate buffer system

Answer 247

A

Transmembrane proteins (glycoproteins)
Role in cell-cell adhesion

Answer 248

A

Transmembrane proteins
Role in cell-extra cellular matrix adhesion

Answer 249

A

Found in the blood are derived from monocytes that originate in the bone marrow
In the tissues may be derived from the embryonic yolk-sac.

Answer 250

A

Build bone; Bone depositing cells; secrete new bone matrix
Promoted by calcitonin

Answer 251

A

Bone resorbing cells; break down old bone
Promoted by PTH

Answer 252

A

structures in operons, which are involved in prokaryotic gene expression.

bind to the repressor

Answer 253

A

upstream DNA sequences in the eukaryotic genome that bind with transcription factors.

Answer 254

A

Insulates axons so that action potentials can move more quickly

Answer 255

A

Gaps in the myelin sheath where Na+ and K+ ions can cross the membrane when gates are open
Result in a strong and consistent signal

Na+ enters at each node of ranvier

Answer 256

A

a state of constant contraction

Answer 257

A

More Blasting Gas, I’m Nervous
Morula
Blastula
Gastrula
Neurulation

Answer 258

A

Outer layer of blastula

Answer 259

A

a fluid-filled central region present in the blastocyst during mammalian embryogenesis.

Answer 260

A

Upregulated: ADP, AMP, inorganic phosphate
Down-regulated: ATP, NADH, citrate

Answer 261

A

contributes to oxidative phosphorylation
or converted back to NAD+ for glycolysis to continue (through ETC or fermentation)

Answer 262

A

pyruvate converted to lactate (by lactate dehydrogenase) in a coupled reaction with conversion. of NADH to NAD+

Answer 263

A

Premature stop codon

Answer 264

A

one nucleotide replaced by an aa that has similar characteristics

Answer 265

A

binds to promoter region; travels along the template strand in the 3’-5’ direction, synthesizing an antiparallel complement in the 5’-3’ direction.
The template strand is known as the antisense strand, and the opposite strand is known as the sense strand (corresponds to the codons on the mRNA that is eventually exported to the cytosol for translation)

Answer 266

A

a string of approximately 250 adenine (A) nucleotides added to the 3’ end of an hnRNA transcript to protect against rapid degradation in the cytosol

Once RNA leaves the nucleus, will rapidly degrade from 3’ end

Answer 267

A

noncoding sequences (introns) are removed and coding sequences (exons) are ligated together.

Answer 268

A

splicing (ie, removal) of noncoding introns as well as the addition of a 3′ poly-adenine (poly-A) tail and a 5’ GTP cap.

Answer 269

A

connects okazaki fragments

Answer 270

A

catalytic efficiency, concentration, inhibitors/activators, temperature, pH

Answer 271

A

It is upregulated by glucagon and the presence of surplus pyruvate/acetyl-CoA
Downregulated by insulin

The steps in glycolysis that require investment of ATP cannot be reversed by gluconeogenesis

Gluconeogenesis takes place in both cytosol and mitochondria (after transport of malate/PEP to cytosol)

Answer 272

A

Digest lipids/fats (often stored as triglycerides)

Answer 273

A

cleave bonds through non-hydrolysis mechanisms

Answer 274

A

join molecules together with covalent bonds

Answer 275

A

active and requires the external intercostal muscles to expand the thoracic cavity, increasing the intrathoracic volume (which causes intrapleural pressure to decrease)

Answer 276

A

passive and initiated by relaxation of the internal intercostal muscles; relaxation causes the chest cavity to decrease in volume

Answer 277

A

less breathing= more CO2
More CO2= more acidic
More acidic= liver will excrete HCO3 (basic)

Answer 278

A

Deoxygenated blood from body tissues enters the right atrium via the (superior and inferior) vena cavae
2, The right atrium contracts, forcing the deoxygenated blood through the tricuspid valve and into the right ventricle.
The right ventricle contracts to propel the blood through the pulmonary valve and into the pulmonary arteries
The pulmonary arteries carry blood from the heart to the capillary beds of lung alveoli, where gas exchange occurs.
In pulmonary capillary beds, the blood unloads carbon dioxide and loads oxygen (ie, becomes oxygenated) and returns to the left atrium via the pulmonary veins.
The left atrium contracts, pushing the oxygenated blood through the bicuspid (mitral) valve and into the left ventricle
The left ventricle contracts to pump blood through the aortic valve to the rest of the body via the aorta.
The blood flowing through systemic blood vessels delivers nutrients and oxygen to the body tissues before returning to the heart.

Answer 279

A

lower in oxygen, higher in CO2 and has a lower pH than arterial blood in the aorta; essentially the same as venous blood.
Passes through the tissues of the body– gives up oxygen and takes on CO2.
It has been pumped through the right side of the heart from the veins and headed for the lung where it will become oxygenated and will dispose of its CO2 load.

Answer 280

A

separates the right ventricle from the pulmonary circulation

Answer 281

A

separates the left ventricle from the aorta

Answer 282

A

when the heart muscle contracts and pumps blood from the chambers into the arteries

Answer 283

A

when the heart muscle relaxes and allows the chambers to fill with blood

Answer 284

A

the force drawing water into a solution by osmosis, the passive movement of water molecules from an area of low to an area of high solute concentration across a semipermeable membrane. Osmotic pressure increases as solute concentration (osmolarity) increases.

increase of osmotic pressure causes water to be retained

Answer 285

A

Force that pushes fluid out of the blood capillaries

Answer 286

A

Force that pushes the fluid into the blood capillary

Answer 287

A

Transport protein made by liver

Prevents loss of fluid from blood vessels/ maintains osmotic pressure

Carries hormones, vitamins, enzymes

Answer 288

A

returns blood from portions of body above the heart

Answer 289

A

returns blood from portions of body below the heart

Answer 290

A

enters right atrium, travels through tricuspid valve, enters right ventricle; on contraction, blood from right ventricle passes through pulmonary valve and enters pulmonary arteries– here it travels to the lungs in smaller vessels; when blood reaches capillaries that line alveoli, gas exchange begins (CO2 leaves, and O2 enters)

Answer 291

A

enters the left atrium, travels through mitral (bicuspid) valve, enters left ventricle; on contraction, blood from left ventricle passes through aortic valve and enters aorta

Answer 292

A

Involved in inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites

Type of leukocyte

Includes neutrophils, eosinophils, basophils

Answer 293

A

Important in specific immune responses

Type of leukocyte

Includes lymphocytes, monocytes

Answer 294

A

Those that mature in lymph nodes/spleen are B cells

Those that mature in the thymus are T cells

B cells generate antibodies

T cells kill virally infected cells and activate immune cells

Answer 295

A

Phagocytize bacteria– once they leave bloodstream and enter organ, they are called macrophages

Answer 296

A

released from megakaryocytes (bone marrow cells) and assist clotting

development stimulated by thrombopoietin

Answer 297

A

production of blood cells/platelets

Answer 298

A

stimulates red blood cell development

Answer 299

A

a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies.

Surface proteins in red blood cells
ABO or Rh factors
Can be targeted by an antibody
Ex. macrophages, dendritic cells, B cells, epithelial cells

Answer 300

A

a type of mechanoreceptors allowing for relaying information derived from blood pressure within the autonomic nervous system

Answer 301

A

sense high blood osmolarity and promote ADH to increase reabsorption of water to increase blood volume and pressure

Answer 302

A

immune cell

identifies foreign pathogen

Answer 303

A

degrade pathogens and dead body cells

Answer 304

A

release chemical mediators (histamine) that enhance immune response

Answer 305

A

release chemical mediators (histamine) that modulate allergic reactions

Answer 306

A

kill and phagocytize bacterial cells

Answer 307

A

defend against parasitic infections and modulate immune responses during allergic reactions

Answer 308

A

release toxins to induce apoptosis virus infected body cells

Answer 309

A

an antibody-mediated immune response by B lymphocytes binding to antigens and dividing to create cells

some new cells will differentiate into short lived plasma cells to secrete antibodies
others will differentiate into long lived memory cells and respond to future infection

Answer 310

A

Skin (defensin enzymes and sweat)
Respiratory system (mucous membranes and lysozyme enzymes secreted in tears and saliva)
GI tract (acidity eliminates pathogens)

Answer 311

A

proteins that prevent viral replication and dispersion– cause nearby cells to decrease production of viral and cellular proteins and decrease permeability so viruses can’t infect

Answer 312

A

Group of membrane bound proteins that display or present antigens for inspection by T cells
MHC I for endogenous antigens (within cell)
MHC II for exogenous antigens (only in phagocytic cells)

All nucleated cells have MHC I molecules, but certain immune cells (eg, macrophages, lymphocytes, dendritic cells) also contain MHC II molecules

Dependent on a cell’s transcriptional and translational machinery

Answer 313

A

Y shaped; made up of 2 heavy chains and 2 light chains held together by disulfide linkages and noncovalent interactions

synthesized and secreted by effector B cells

a variable region that interacts with a specific antigen, and a constant region that interacts with the cells (eg, phagocytes) and proteins of the body to facilitate antigen destruction.

Answer 314

A

Helper T cells (CD4+)– secrete lymphokines
Cytotoxic T cells (CD8+)– directly kill virally infected cells
Suppressor/regulatory T cells– express CD4 and Foxp3– tone down immune response once infection contained

Answer 315

A

Duodenum
Jejunum
Illium

Answer 316

A

secreted by G cells and stimulates secretion of HCl

Answer 317

A

Secrete pepsinogen into the stomach, where its active form (ie, pepsin) aids in protein digestion

Answer 318

A

produce mucus and bicarbonate, which both function to protect the walls of the stomach from self-destruction in the stomach’s acidic, proteolytic environment

Answer 319

A

secrete H ions as hydrochloric acid; cleave pepsinogen into pepsin; secrete intrinsic factor

Answer 320

A

Produces bile (salts, cholesterol, bilirubin) and albumin (transport hormones, filter toxins, stores/creates energy stores by storing nutrients as glycogen/triaglycerols or undergoing gluconeogenesis/glycogeneolysis)

Receives blood draining from digestive tract through hepatic portal vein

Answer 321

A

cleaves trypsinogen into trypsin

Answer 322

A

Secretin and Cholecystokinin

Answer 323

A

Maltase: digests maltose
Exopeptidase: removes aas until dipeptides are left
Nuclease: digests RNA and DNA
Dipeptidase: digests dipeptides into single amino acids
Lactase: digests lactose
Sucrase: digests sucrose

Answer 324

A

Lipase- digests triglycerides in fats and glycerol
Amylase- digests starch into maltose
Phospholipase- digests phospholipids into fatty acids + glycerol and phosphate group
Insulin- regulates glucose in blood
Endopeptidase- digests proteins into polypeptides

Answer 325

A

takes place in the glomerulus
capillaries meet in nephron, part of fluid passes through the Bowman’s capsule; fluid comes from our blood and contains water, nutrients, and waste (urea)

Answer 326

A

Where reabsorption of protons and bicarbonate from filtrate contributes to acid base balance within the body

Answer 327

A

glomerulus
bowman’s capsule
proximal convoluted tube (descending)
loop of henle
proximal convoluted tube (ascending)
distal convoluted tube
collecting duct

All within cortex of the kidney

Answer 328

A

focus on keeping what body needs and losing what it doesn’t

Answer 329

A

focus on the volume and concentration of urine

Ascending loop is permeable to salts
Descending loop is permeable to water

Answer 330

A

collection of blood vessels where fluid is displaced

Answer 331

A

renal artery brings in impure blood to kidney
renal vein sends away filtered blood

Answer 332

A

Inner part of kidney containing renal pyramid

Answer 333

A

released as a result of low BP

from juxtaglomerular cells of kidney

cleaves angiotensin to promote release of aldosterone

Answer 334

A

a peptide hormone synthesized by the hypothalamus and released by posterior pituitary

allows more water to be reabsorbed by making cell junctions of duct leaky

Answer 335

A

increase; this would promote retention of sodium ions and promote osmotic reabsorption of water by kidneys

Answer 336

A

water absorption increases and solute extrection increases

Answer 337

A

movement of solutes from filtrate back into blood

Answer 338

A

Lowest in cortex, then medulla, then most in renal pelvis

Gradient allows water to be reabsorbed; excretion of concentrated urine limits water loss and preserves blood volume

Answer 339

A

basic contractile unit; made of thick and thin filaments

thick filaments: organized bundles of myosin

thin filaments: actin/troponin/tropomyosin

Answer 340

A

released into cytosol from SR

Induced when a depolarizing current runs along sarcolemma and down T tubules

Answer 341

A

released at neuromuscular junction via exocytosis from presynaptic motor neurons

binds to receptors on motor end plate and TRIGGERS MUSCLE CONTRACTION

Answer 342

A

(after Ca+ binds so myosin can bind) conformational change causes the actin filament to slide relative to the myosin

ATP binds myosin, causing it to detach and recharge

Answer 343

A

Fast twitch
Have less mitochondria; rely on glycolysis and fermentation for ATP

Answer 344

A

Slow twitch, more mitochondria to carry out ox. phos. and high myoglobin

Answer 345

A

muscle to bone

Answer 346

A

bone to bone

Answer 347

A

Both phenotypes fully present

Answer 348

A

Phenotypes combined

Answer 349

A

Population is large w no genetic drift
No mutations that affect the gene pool
Mating is random
No migration in or out of population
Genes are all equally successful at reproducing

Answer 350

A

GAVCPLIMWF
Glycine
Alanine
Valine
Cysteine
Proline
Leucine
Isoleucine
Methionine
Tryptophan
Phenylalanine

Answer 351

A

KRH
Lysine
Arginine
Histidine

Answer 352

A

DE
Aspartic Acid
Glutamic Acid

Answer 353

A

STYNQ
Serine
Threonine
Tyrosine
Asparagine
Glutamine

Answer 354

A

Longer than 20 amino acid chain residues

Less than 20= oligopeptide

Answer 355

A

catalyze hydrolysis; only cleave at specific points in peptide chain

Answer 356

A

A, D, E, K

Answer 357

A

Complex I

electrons flow from NADH -> FMN -> CoQ to form CoQH2

We’re in the kitchen. Someone orders Nuggets (NADH) and Fries (FMN) for the cook (CoQ) to prepare.

Complex II

succinate -> FAD -> FADH2 -> CoQ to form CoQH2

Someone orders salad (succinate) and falafel (FAD/FADH2) for the cook (Coq) to prepare.

Complex III

The food has been made and the cook with the food (CoQH2) hands it off to the host (heme) who brings the food to the customer (cytochrome C)

Complex IV

now that the customer (cytochrome c) has the food, in order to eat it, their mouth has to make an O (oxygen)

Answer 358

A

Fluid is collected by lymph capillaries, flows into larger lymph vessels, and is transported into lymph ducts that drain into veins near the heart.

Answer 359

A

recognize foreign antigens displayed by MHC proteins of other immune cells, such as:

B lymphocytes, cells that bind and engulf a foreign antigen. The antigen is broken down into fragments within the B lymphocyte, and these fragments are transported to be displayed on MHC proteins present on the cell membrane. A helper T cell binds the foreign antigen presented by the B lymphocyte and releases signaling molecules (cytokines) that induce division of the B lymphocyte into many identical cells, some of which differentiate to secrete antibodies against the invading pathogen.

Macrophages and dendritic cells, which engulf foreign antigens (via phagocytosis) and present these antigen fragments on the MHC proteins found on their cell membrane. Upon binding these antigens, helper T cells release cytokines that enhance other immune responses, including the phagocytotic activity of macrophages and the activation and proliferation of cytotoxic T cells, immune cells that release toxins to induce apoptosis in infected cells.

Answer 360

A

Transport of a single molecule is called uniport.

When two molecules are transported in the same direction, it is known as symport

When two molecules are transported in opposite directions, it is called antiport.

Answer 361

A

malonyl-CoA
similar structure to acetyl CoA

fatty acid synthase carries out reaction; contains acyl carrier protein

Answer 362

A

More ADP present, less ATP produced

Answer 363

A

consume water to break bonds

Answer 364

A

join two molecules together, and release one or more water molecules in the process

Answer 365

A

Low binding affinity

Answer 366

A

An intermediate in several metabolic pathways, including gluconeogenesis, the citric acid cycle, and amino acid degradation.

Precursors:

In gluconeogenesis, pyruvate carboxylase catalyzes the carboxylation of PYRUVATE to form oxaloacetate. In this reaction, CO2 is added to pyruvate, and ATP is hydrolyzed to provide the necessary energy.

In the final step of the citric acid cycle, oxaloacetate is synthesized by the oxidation of MALATE, a reaction catalyzed by malate dehydrogenase. This reaction requires the simultaneous reduction of NAD+ to NADH. NADH can then enter the electron transport chain and provide electrons necessary for the production of ATP.

In amino acid degradation, amino acids are converted to α-keto acids by transamination, in which an amino group is transferred from an amino acid to α-ketoglutarate to synthesize glutamate. The α-keto acid derivative of ASPARTATE is oxaloacetate.

Answer 367

A

less than .05

Answer 368

A

the number of reactions each enzyme catalyzes per second under saturating conditions

Answer 369

A

Kcat x Enzyme Conc.

Answer 370

A

The y-intercept represents the reciprocal of the maximum reaction velocity 1/Vmax; the x-intercept represents the negative reciprocal of the enzyme’s Michaelis constant −1/Km; and the slope of the line is the ratio Km/Vmax.

Answer 371

A

During periods of fasting, the liver helps maintain blood glucose levels. The liver initially synthesizes glucose by degrading glycogen. However, after glycogen stores are depleted in prolonged fasting, gluconeogenesis is upregulated, increasing the synthesis of glucose from precursors such as pyruvate. In the fasting state, the liver downregulates key enzymes of glycolysis and upregulates enzymes of gluconeogenesis.

During fasting, glucose consumption and storage are downregulated in the liver and glucose synthesis is upregulated. Newly formed glucose is exported into the blood to keep levels constant. In the early stages of fasting, the liver synthesizes glucose by degrading glycogen (glycogenolysis). However, if fasting is prolonged, glycogen stores are depleted, and the liver must upregulate the synthesis of glucose from smaller precursor molecules (gluconeogenesis).

Answer 372

A

In the well-fed state, pyruvate carboxylase is downregulated so that pyruvate can be used in other pathways

During prolonged fasting, pyruvate carboxylase activity is upregulated in the liver to increase the rate of gluconeogenesis.

Answer 373

A

Less polar compounds will elute faster

Used to separate and collect macromolecules besides proteins

Answer 374

A

Small molecules will slow down while large molecules quickly move around the pores

Answer 375

A

X Ray Crystallography and NMR

Answer 376

A

Vertical lines represent going into the page (dashed lines)
Horizontal lines represent going out of the page (wedges)
All D-sugars have the hydroxide on the right, and L-sugars have the hydroxide on the left

Answer 377

A

Contain both a hydroxyl group and a carbonyl group

Can undergo intramolecular reactions to become cyclic hemiacetals and hemiketals

Answer 378

A

furanose and pyranose

Answer 379

A

α-glucose has the –OH group of C-1 trans to the CH2OH substituent (axial and down)

β-glucose has the –OH group of C-1 cis to the –CH2OH (equatorial and up)

Answer 380

A

will have only single bonds!

tend to be solid at room temp

Answer 381

A

contain double bonds which introduce kinks and make it difficult to stack

have lower melting point due to decreased van der waals forces from lack of stacking

tend to be liquid at room temp

Answer 382

A

important in the body for absorption of fat soluble vitamins and lipids

Answer 383

A

5’ end will have OH or phosphate bonding to C5’ of sugar
3’ end will have a free OH on the C3’ of sugar

Answer 384

A

created as nucleotides are joined by 3’-5’ phosphodiester bonds (3’ carbon of one sugar to 5’ phosphate of the next)

Answer 385

A

cyclic, planar, conjugated (alternating single/multiple bonds)
Huckel’s rule: 4n + 2 p electrons

Answer 386

A

compacted, inactive chromatin; composed of deacetylated histones

Answer 387

A

dispersed, active chromatin

Answer 388

A

in DNA, introduce negative supercoils which alleviate torsional stress; work ahead of helicase to nick one or both strands

Answer 389

A

strand of replication fork that is continuously copied in same direction as advancing replication fork

Answer 390

A

strand that is copied in opposite direction to that of the replication fork

Answer 391

A

DNA polymerases a & s work together to synthesize both the leading and lagging strands. DNA s also fills in the gaps left behind when RNA primers are removed

DNA polymerase g replicates mitochondrial DNA

DNA polymerase b & e are used in the process of DNA repair

DNA polymerase b & e are assisted by PCNA protein. This assembles into a trimer to form a sliding clamp, that helps to strengthen the interaction between these DNA polymerases and the template strand

Answer 392

A

mutated genes that cause cancer

proto oncogenes are before oncogenes are mutated

Answer 393

A

demination converts cytosine to uracil
uracil detected and removed
hole filled with correct base by DNA polymerase and sealed by ligase

Answer 394

A

produces millions of copies of DNA sequence without amplifying DNA in bacteria

combine target sequence, heat stable DNA polymerase, primers (short pieces of DNA complementary to each end of the target sequence), and deoxynucleotides

Answer 395

A

denaturation
annealing
DNA synthesis

Answer 396

A

a cloned gene that is introduced for an experiment

often microinjected into the nucleus of a newly formed ovum

Answer 397

A

carries information that specified the amino acid sequence of the protein to the ribosome

the only type of RNA that contains info to be translated into a protein

Answer 398

A

converts language of nucleic acids to language of amino acids and peptides

Answer 399

A

important for protein assembly

may function as ribozymes– enzymes made of RNA molecules instead of peptides

Answer 400

A

recognized by a complementary anticodon on the tRNA

Answer 401

A

after first two nucleotides on an mRNA codon which require traditional base pairing, the third may undergo less stringent base pairing at third position of of the codon and anticodon

mutations here are silent (degenerate)

Answer 402

A

Cytoplasm

DNA may not leave the nucleus and uses RNA to transmit info

Answer 403

A

creation of mRNA from a DNA template

produces a copy of only one of the two strands

Answer 404

A

DNA strand that is not used as a template for mRNA

Has exact same codons as mRNA strand (except ts replaced by us)

Answer 405

A

primary product of transcription

mRNA is derived from this

Answer 406

A

occur at separate times in separate locations

Answer 407

A

Initiation: small subunit binds to 5’ cap structure- Kozak sequence (euk) or Shine Dalgarno sequence (prok)

Elongation:
peptide chain is made longer

Termination: ribosome encounters stop codon

Answer 408

A

Cluster of genes transcribed as a single mRNA

Answer 409

A

Binds a repressor protein so that cell will stop producing proteins for metabolism and wasting energy

Answer 410

A

where RNA polymerase binds

Answer 411

A

codes for a repressor protein

Answer 412

A

contain genes involved in the metabolism of a specific substrate– the expression of the operons is induced in the presence of the substrate

Positive control mechanisms; binding of a molecule increases transcription

ex. Lac operon; in order to be expressed, lactose must be present; if not present, operator will bind to repressor

Answer 413

A

contain genes encoding enzymes require for a biosynthetic pathway

Negative feedback

Ex. tryptophan– when it is the final protein, acts as a corepressor when concentrations get too high

product of biosynthetic pathway controlled by operon regulates expression of operon

Answer 414

A

the process by which DNA is transferred from one bacterium to another by a virus

Answer 415

A

transfer of genetic material, ordinarily in the form of a plasmid, between bacterial cells by direct cell-to-cell contact or via a bridge-like connection between two cells

the transfer of a plasmid through a bridge that is created when a sex pilus on one bacterium (often known as F+, which refers to the presence of the fertility factor, or as male) attaches to another bacterium (generally known as F−). During this process, the fertility factor itself is duplicated and transferred, converting the F− cell into an F+ cell.

proceeds unidirectionally, from a bacterium possessing the F factor (and hence able to form a pilus) to a bacterium lacking the factor.

Answer 416

A

the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cellular membrane

the simple uptake of DNA (either a linear fragment or a plasmid) from a recipient bacterium’s extracellular fluid through membrane pores or transport proteins.

Answer 417

A

development of new blood vessels

Answer 418

A

exclusively thin filaments

Answer 419

A

exclusively thin filaments

Answer 420

A

exclusively thick, myosin filaments

Answer 421

A

area in the center where thick and thin filaments overlap

“all the myosin” is located here

does not move when muscles contract

Answer 422

A

delineate regions between adjacent sarcomeres; give striped appearance

does not change in response to contraction

Answer 423

A

Glycolysis, TCA and ETC are triggered when the Energy levels are low. These are primarily signaled by Low ATP and high ADP levels

Gluconeogenesis is triggered by low Blood Glucose. A healthy blood glucose level has its own purpose aside from Energy. This cycle can turn on regardless of if the ATP levels are high or low. This is because Glucose setpoints will act as a homeostasis marker of health for our cells just like temperature, pH and ionic concentrations

Pentose Phosphate Pathway is triggered by the need to prepare for nucleotide synthesis and dealing with Reactive Oxygen Species

Beta Oxidation is triggered when energy levels and glucose levels are low. But ultimately it is connected to a timing factor of waiting to finish the 12-18hours

Glycogenolysis is also triggered by low blood glucose levels in response to Glucagon. But it is more connected to energy levels during the 12-18 hour window

Glycogen Synthesis and Fatty Acid Synthesis is triggered by having excessive resources

Answer 424

A

hexokinase
phosphofructokinase (stimulated by insulin and inhibited by glucagon)
pyruvate kinase

Answer 425

A

less energy efficient

converts pyruvate to lactate or ethanol (produce CO2 and ethanol) to replenish NAD+
Will not be converted to acetyl CoA or enter CAC

Answer 426

A

pyruvate fed into ox phos, pyruvate oxidation, CAC, etc

Answer 427

A

solute concentrations in the blood are high (in other words, the blood is very concentrated). This would provoke the body to attempt to conserve water, not excrete it

Answer 428

A

produces DNA from an RNA template

Answer 429

A

nourish the developing sperm cells

activated by FSH

Answer 430

A

follicular cells closely associated with the developing female oocyte (egg). They function to convert thecal androgens to estradiol prior to ovulation. After ovulation, they give rise to the corpus luteum and begin producing high levels of progesterone.

Answer 431

A

catecholamine-secreting neuroendocrine cells of the adrenal medulla.

Answer 432

A

adjacent to the seminiferous tubules in the testicles. In response to stimulation by LH, they produce testosterone and other androgens.

Answer 433

A

In the sperm contains mitochondria, which generate ATP from fructose. This energy is used to propel the sperm through the female reproductive tract by utilizing a flagellum.

Answer 434

A

contains the genetic material and is also covered by an acrosome, which is necessary to penetrate the ovum.

Answer 435

A

response elements outside of promotor region

can enhance transcription levels

a DNA region that is able to bind transcriptional activators in order to increase the expression of a particular gene.

Answer 436

A

add methyl groups to cytosine and adenine nucleotides

methylation linked with silencing

heterochromatin regions more heavily methylated

Answer 437

A

one fatty acid chain of a triglyceride is substituted with a phosphate group

Answer 438

A

prevent solutes from leaking into space between cells

found in epithelial cells, function as a physical link between them

Answer 439

A

bind adjacent cells by anchoring to their cytoskeletons

formed by interactions between transmembrane proteins and their associated intermediate filaments

Answer 440

A

concentration of solutes inside the cell higher than the surrounding solution

Answer 441

A

dependent on the concentration of dissolved particles, not chemical identity

Answer 442

A

equal to number of particles obtained from the molecule when in solution

Answer 443

A

cell membrane invaginates and engulfs materials to bring it into the cells

Answer 444

A

endocytosis of fluids and dissolved particles

Answer 445

A

ingestion of large solids like bacteria

Answer 446

A

when secretory vesicles fuse with the membrane and materials are released from the inside of the cell to the extracellular environment

Answer 447

A

determines membrane potential from intra and extracellular concentrations of various ions

Answer 448

A

highly permeable; has many large pores for ions and small proteins to pass through

Answer 449

A

more restricted permeability; contains cristae (interfoldings that increase available surface area)

Answer 450

A

where CAC produces high energy electron carriers that are used in the ETC

Answer 451

A

GLUT 2 and 4 are highly regulated

glut 2: low affinity transporter in hepatocytes and pancreatic cells; higher kM value (14 mM)

glut 4: responds to glucose concentration in peripheral blood; found in adipose tissue and muscles; kM value ~same as glucose (-5mM)

Answer 452

A

Hexokinase and Glucokinase
First step in glucose metabolism is to transport it across the membrane and then phosphorylate it by kinase enzymes within the cell to prevent glucose from leaving via the transporter
Kinases attach a phosphate group from ATP to their substrates
Glucose enters the cell by facilitated diffusion or active transport
Kinases convert glucose to glucose 6-phosphate
GLUT transporters are specific for glucose and not for phosphorylated glucose, so the converted glucose cannot leak out of the cell.
Hexokinase: widely distributed and is inhibited by its product, glucose 6-phosphate
Glucokinase: found in liver cells and pancreatic beta-islet cells
In liver, glucokinase is induced by insulin
Phosphofructokinases (PFK-1 & PFK-2)
Phosphofructokinase-1: Rate limited enzyme and main control point of glycolysis
Reaction involves fructose 6-phosphate being phosphorylated to fructose 1,6-biphosphate by using ATP
PFK-1 is inhibited by ATP and citrate, and activated by AMP
Cell should turn off glycolysis when it has sufficient energy and turn on glycolysis when it needs energy (high AMP)
Citrate is an intermediate of the citric cycle, so high citrate levels imply that the cell is producing enough energy
Insulin stimulates and glucagon inhibits PFK-1 in hepatocytes indirectly through PFK-2 and fructose 2,6-biphosphate
Insulin activates PFK-2, which then converts a tiny amount of fructose 6-phosphate to fructose 2,6-biphosphate.
F2,6-BP activates PFK-1
Glucagon inhibits PFK-2, which lowers the levels of F2,6-BP which then inhibits PFK-1.
PFK-2 is found mainly in the liver
When PFK-1 is activated, it allows for cells to override the inhibition caused by ATP so that glycolysis can continue – glycolysis continues even when the cell is energetically satisfied because the metabolites can be fed into the production of glycogen, fatty acids, and other storage molecules
Glyceraldehyde-3-Phosphate Dehydrogenase
Catalyzes an oxidation and addition of an inorganic phosphate (Pi) to its substrate: glyceraldehyde 3-phosphate.
Results in the production of a high energy intermediate: 1,3-biphosphoglycerate and also the reduction of NAD+ to NADH
NADH can then be oxidized by the mitochondrial electron transport chain, which provides energy for ATP, if oxygen is present.
3-Phosphoglycerate Kinase
Transfers high-energy phosphate from 1,3-biophosphoglycerate to ADP
This results in the formation of ATP and 3-phosphoglycerate
This is an example of a substrate-level phosphorylation reaction: ADP is directly phosphorylated to ATP by using a high-energy intermediate
This is not dependent on oxygen, so it is the only means of ATP generation in anaerobic tissue
Pyruvate Kinase
Last enzyme in aerobic glycolysis
Catalyzes a substrate-level phosphorylation of ADP using the high-energy substrate phosphoenolpyruvate (PEP)
Pyruvate Kinase: activated by fructose 1,6-biphosphate from the PFK-1 reaction
Feed-Forward activation: products of an earlier reaction of glycolysis (F1,6-BP) stimulate, or prepare, a later reaction in glycolysis (activating pyruvate kinase)

Answer 453

A

glycolysis intermediate; used in hepatic and adipose tissue for triacylglycerol synthesis

Answer 454

A

high energy intermediates used to generate ATP by substrate level phosphorylation

Answer 455

A

nonpolar compounds have a higher rF

Answer 456

A

takes place in complex IV, where O2 gets reduced to become water. The electrons needed to reduce oxygen are provided by reduced cytochrome C (cyt-Cred), which is converted to its oxidized form (cyt-Cox) in the reaction catalyzed by complex IV.

Answer 457

A

driven by protons crossing the inner mitochondrial membrane through ATP synthase. When protons are transported across the membrane by means that bypass ATP synthase, the energy released in the process cannot be used to produce ATP. This phenomenon is known as “decoupling” because proton transfer is no longer coupled to ATP synthesis.

Answer 458

A

An increase in the release of neurotransmitter by the presynaptic neuron and an increase in the number of receptors in the postsynaptic neuron.

Potentiation: increase in strength of nerve impulses along pathways which have been used previously

Answer 459

A

sensory receptors that continue to produce action potentials throughout the duration of a stimulus.

limited to peripheral nervous system

Answer 460

A

refers to both increases in neuronal connections, known as potentiation, and decreases in neuronal responses, known as depression

Answer 461

A

Synaptic changes are associated with both immediate and more delayed potentiation or depression.

At the structural level, sprouting (increased connections between neurons), rerouting (new connections between neurons), and pruning (decreased connections between neurons) contribute to structural plasticity.

Structural plasticity does not happen quickly, so it is not responsible for immediate changes

Answer 462

A

(the removal or destruction of tissue) is a technique used to study the brain by measuring the deficits that result from ablation of specific brain areas.

Answer 463

A

remove phosphate groups from molecules by hydrolysis, yielding the dephosphorylated substrate and inorganic phosphate (Pi)

Answer 464

A

break bonds by adding P across them.

process by which Glycogen is cleaved into glucose-1-phosphate

Answer 465

A

the amount of enzyme present

Answer 466

A

In the mitochondria, pyruvate undergoes three decarboxylation reactions as it is converted to acetyl-CoA and enters the citric acid cycle.

The metabolic fate of carbon atoms in pyruvate precursors is most commonly to be released as CO2.

Answer 467

A

Fermentation in higher eukaryotes converts pyruvate to lactate

bacteria and lower eukaryotes such as yeast it converts pyruvate to ethanol.

Answer 468

A

begins with a start codon (AUG) ends with a stop codon (UGA, UAA, UAG)
(read 5’-3’)

Answer 469

A

Sensory receptors (specialized nerve endings) detect a stimulus (eg, chemical, pressure).

The stimulus activates the sensory neuron, which sends an afferent signal (ie, electrical impulse) toward spinal cord integration centers (regions that process sensory and CNS input).

Within the integration center, the signal may be passed directly to an effector neuron or to an interneuron that relays the signal to the effector neuron. For supraspinal reflexes, interneurons can also relay sensory signals to the brain and integrate brain signals to regulate reflex responses.

The activated effector neuron generates an efferent signal that travels from the spinal cord to the target tissue (eg, muscle), which carries out the appropriate response.

Answer 470

A

Proteins are extracted (eg, from tissue such as a spinal cord segment)

Gel electrophoresis is performed on the proteins to separate them by size. Larger proteins will migrate a shorter distance through the gel than smaller proteins.

Proteins are transferred from the gel to a protein-binding membrane (eg, nitrocellulose), where they are immobilized.

Protein-rich mixtures are used to block portions of the membrane to which proteins were not transferred. This prevents antibodies (ie, another type of protein) from binding nonspecifically to the membrane in steps 5 and 6.

The membrane is incubated with primary antibodies that bind specific proteins.

Secondary antibodies, which include fluorescent labels, are applied and bind primary antibodies.

Antibodies bound to the proteins are detected via fluorescence, allowing specific protein bands to be visualized. Thicker bands indicate that the protein is more highly expressed.

Answer 471

A

transfer of genes between species

Refers to closeness on the same chromosome

Answer 472

A

Upon binding foreign antigens, activated B lymphocytes divide and differentiate into antibody-secreting plasma cells and long-lived memory B cells that can more rapidly respond to foreign antigens in the event of future infections.

Answer 473

A

Both: bone marrow stem cells

Innate immune cells respond to many types of antigens and signals of stress
Adaptive respond to only a single type of antigen

Innate responds immediately
Adaptive responds in several days

Innate will generally respond the same to future infections
Adaptive will be more enhanced with each infection (memory B and T cells)

Answer 474

A

occurs when multiple presynaptic neurons release neurotransmitters together to fire an action potential

Answer 475

A

occurs when a single presynaptic neuron releases neurotransmitters to generate the action potential

Answer 476

A

major excitatory neurotransmitter in the brain

an amino acid neurotransmitter, which necessarily utilizes cell surface receptors that are integrated into the plasma membrane.

Answer 477

A

the main inhibitory neurotransmitter of the CNS; it hyperpolarizes cells to reduce action potential firing.

alcohol is a GABA agonist– so the effects of GABA are associated with alcohol intoxication.

(Glycine is another inhibitory neurotransmitter found in the spinal cord and brainstem that can work in conjunction with GABA.)

Answer 478

A

Tm tends to be larger for molecules that have a higher guanine-cytosine (GC) content, since guanine and cytosine are held together by three hydrogen bonds, whereas adenine and thymine are attached by only two.

Answer 479

A

read the parental nucleotide template in the 3’ → 5’ direction, adding nucleotides to the growing strand in the 5’→ 3’ (antiparallel) direction.

Answer 480

A

Cholesterol
glucocorticoids (cortisol and cortisone)
mineralocorticoids (aldosterone)
testosterone, estrogen, progesterone

Answer 481

A

FSH
LH
ACTH
TSH
Prolactin
endorphins
growth hormone
ADH (aka Vasopressin)
oxytocin
calcitonin
PTH (parathyroid hormone)
glucagon
insulin
somatostatin
erythropoietin
atrial natriuretic peptide (ANP)
thymosin

Answer 482

A

T3 and T4, epinephrine and norepinephrine

Answer 483

A

the process by which antibodies bind to and recognize antigens on the surface of a pathogen. The antibodies then attract macrophages to phagocytose the invader.

Answer 484

A

would mean that more glucose would be moved out of the bloodstream and into the cells.

Therefore, increased levels of insulin would most likely be correlated with low levels of blood glucose

Answer 485

A

formed by free-radical attack on a lipid. Thus, we expect the location with the most lipid perioxidation to be someplace where oxygen is participating in a redox reaction. As it so happens, the electron transport chain, which is located on the inner mitochondrial membrane, has oxygen as its terminal electron acceptor.

Loation: inner mitochondrial membrane

Answer 486

A

DNA is normally negatively supercoiled. This is naturally prevalent, because it prepares the molecule for processes that require separation of the DNA strands.

Answer 487

A

it is a parallel circulatory system that drains interstitial fluid from the space surrounding the cells of the tissue. At any given moment, an adult human has about 10 liters of such fluid, which moves from the capillary beds into the extracellular space in the issues. In order to regulate fluid balance throughout the body, some fluid will always be recycled through the circulatory system.

Lymph capillaries collect this fluid and empty into lymph vessels, which converge into the right and left lymphatic ducts. These ducts in turn empty into the circulatory system at the intersection of the internal jugular veins and the right and left subclavian veins, respectively.

The lymphatic system also has a connection with the digestive system because it is used to transport lipids, in the form of chylomicrons, to the circulatory system.

Answer 488

A

membrane receptors. They have transmembrane domains and experience some form of conformational change after binding with a ligand. The ligands that bind and activate these receptors include light-sensitive compounds, molecules involved in odors, hormones, and neurotransmitters, and vary in size from small molecules to peptides to large proteins. When a GPCR undergoes a conformational change, it associates with and allosterically activates a G protein on the intracellular side of the membrane.

promote depolarization or hyperpolarization, depending on the specific GPCR. In addition, GPCRs generally rely on signal transduction via second messengers, so their contribution to depolarization would be less direct than opening ligand-gated ion channels for more immediate ion flow.

Answer 489

A

When bound to GDP, G proteins are inactive, but they become activated by binding to GTP. An intracellular component of the G protein receptor facilitates the exchange of a molecule of GDP for GTP at the α-subunit of the G protein.

Answer 490

A

The 3′-hydroxy group of the deoxyribose binds via phosphodiester linkage to the 5′-phosphate group of another deoxyribonucleotide monomer.

Nucleotides are linked to one another by phosphodiester bonds between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide in a way that the 5′ end bears a phosphate, and the 3′ end a hydroxyl group.

Answer 491

A

Reverse transcriptase (an enzyme) is used to convert mRNA to double-stranded cDNA, which can then be amplified through PCR using primers specific to the mRNA transcript of interest.

Answer 492

A

Retroviruses are a class of enveloped viruses that have RNA genomes.
Upon entering a host cell, the envelope and capsid disassemble, releasing viral RNA and proteins into the cytoplasm of the host cell.
Viral reverse transcriptase converts viral RNA into double-stranded (ds) DNA that is then transported into the nucleus.
A specialized enzyme called integrase facilitates the integration of the viral DNA into the host genome. Once integrated, viral DNA is replicated along with the host genome, and transcription and translation of viral DNA produce RNA and proteins that are assembled into new viruses.

Answer 493

A

segments of DNA that move between different areas of the genome and can be classified as either DNA transposons or retrotransposons.

The retrotransposon is initially transcribed into mRNA, which is then transported into the cytoplasm and translated to produce reverse transcriptase and integrase. Reverse transcriptase produces dsDNA from the mRNA, and integrase facilitates the integration of the dsDNA into a new area of the genome.

Answer 494

A

inspiratory muscles contract (eg, the diaphragm moves downward) to increase the volume of the thoracic cavity.
- increased intrapulmonary volume and an inversely proportional decrease in intrapulmonary pressure.

Air pressure will drop below atmospheric, causing air flow high pressure in atmosphere into low pressure of lungs until intrapulmonary pressure = atm pressure

Answer 495

A

inspiratory muscles relax (eg, the diaphragm moves upward) to decrease the volume of the thoracic cavity.
- The lungs recoil to fit smaller space, which leads to a decrease in intrapulmonary volume and inversely proportional increase in intrapulmonary pressure (until it is higher than atmospheric pressure).

Air flows down its pressure gradient - forced out of the higher-pressure environment in the lungs and into the lower-pressure environment of the atmosphere.

Answer 496

A

molecules that relay signals from receptors on the cell surface to target molecules in the cell, cytoplasm, or nucleus

Answer 497

A

a collection of nerve cell bodies in the PNS ; the site where preganglionic nerves synapse with postganglionic nerves.

Both sympathetic and parasympathetic responses are transmitted along preganglionic fibers from the central nervous system and postganglionic fibers that synapse with the target tissue responsible for a response.

provide relay points and intermediary connections between neurological structures in the body, such as the PNS and CNS.

Answer 498

A

Both sympathetic and parasympathetic preganglionic neurons release acetylcholine from their nerve terminals.

However, the neurotransmitter released at the target tissue by the postsynaptic neuron varies for sympathetic and parasympathetic pathways:
- acetylcholine typically released in parasympathetic pathways
- norepinephrine typically released in sympathetic pathways.

Answer 499

A

either cholinergic (releasing acetylcholine (ACh)), or adrenergic (releasing norepinephrine (NE)).

Note that preganglionic neurons of the ANS release ACh. Postganglionic neurons of the PNS also release ACh, but postganglionic neurons of the SNS generally release NE instead.

Answer 500

A

depolarize post synaptic neuron and make it more positive and more likely to transmit message

Answer 501

A

depolarize post synaptic neuron to make it more negative and less likely to fire a message

Answer 502

A

mediates skeletal muscle movement.

Answer 503

A

An environmental event is detected by sensory receptors (nerve endings that respond to specific stimuli (eg, chemical, light, pressure, vibration))

The activated sensory neuron sends afferent sensory signal (in the form of an electrical impulse) toward the CNS, (where the signal is transmitted to an interneuron or effector neuron)

Components of the CNS, interneurons in the brain and spinal cord act as integration centers that process and consolidate sensory and CNS input from multiple locations. Interneurons can relay sensory information to the brain and integrate signals into the reflex response. Interneurons can also transmit the signal directly to the effector neuron (and interneurons are not present in every reflex arc), so input from the brain is not always necessary for the completion of a reflex.

The effector neuron generates and sends an efferent signal that travels toward the target organ (typically, a muscle or gland). (Note: Efferent information exits the CNS.)

The effector (target) organ generates the desired response to the stimulus.

Answer 504

A

include both somatic and autonomic reflexes. Somatic reflexes can be monosynaptic or polysynaptic whereas autonomic reflexes are always polysynaptic.

Answer 505

A

characterized by the presence of plaques composed of beta amyloid proteins and neurofibrillary tangles composed of tau proteins.

Answer 506

A

composed of unmyelinated neuronal cell bodies and dendrites.

Answer 507

A

composed of myelinated and unmyelinated axons that allow for long-distance communication between neurons

this is where afferent axons carry sensory information to the brain and efferent axons carry motor commands to the body.

Answer 508

A

Axon, synapse, dendrite, soma

Answer 509

A

transfer information from one cell to another via passive ionic current flow through gap junctions.

Answer 510

A

use neurotransmitters to transfer information, which is a slower process than electrical synapse

Answer 511

A

Neutrophils, macrophages, natural killer cells

Answer 512

A

both B cells and T cells (eg, cytotoxic T cells, helper T cells)

Answer 513

A

also sweat/sudoriferous glands; are glands in which the product (eg, sweat) is secreted through a duct onto the skin or epithelial lining of a cavity inside the body.

Most exocrine glands are composed of cells lining the open space (lumen) of the duct, as a pathway for the product to travel to the body surface or cavity.

Answer 514

A

occurs when the smooth muscle surrounding the blood vessels relaxes.

Answer 515

A

an endothermic process that absorbs heat from body

Answer 516

A

acts as an insulator and a shock absorber

Answer 517

A

the process whereby B or T cell clones responsive to an antigen are stimulated to replicate and greatly increase in number in contrast to nonresponsive B or T cells, which do not increase in number.

Answer 518

A

bind foreign antigens displayed by other cells (ie, immune cells, infected cells). Helper T cells release cytokines that enhance immune responses whereas cytotoxic T cells promote the apoptotic death of infected cells.

Answer 519

A

has 5 strata; It is composed of epithelial tissue and is continuously sloughed off (superficial layer) and reproduced (deep layer).

Merkel cells, Langerhans cells, melanocytes, and keratinocytes are all cell types in the epidermis.

Answer 520

A

originate in the bone marrow and differentiate into myeloid or lymphoid progenitor cells. Lymphoid progenitor cells go on to become T cells, B cells, or natural killer cells whereas myeloid progenitor cells differentiate into erythrocytes, megakaryocytes, neutrophils, basophils, eosinophils, monocytes, or mast cells.

Answer 521

A

bone marrow

Answer 522

A

B cells and T cells that mediate recognition and destruction of self-antigens are typically destroyed

Answer 523

A

antibody molecules that are secreted by plasma cells

Answer 524

A

more stabiility and higher melting point

Answer 525

A

bind carbohydrates together

are cleaved via a hydrolysis reaction

Answer 526

A

Endocrine signals are released into the blood in order to impact tissues scattered throughout the body.

Paracrine and autocrine chemical messengers act locally.

Paracrine chemical messengers act on cells near the cell that secretes the messenger

Autocrine chemical messengers act on the same cell that secretes the messenger.

Answer 527

A

no- these are proteins with carb groups attached to the polypeptide chain that support the immunological response

Answer 528

A

releases energy

Keq > 1

Answer 529

A

requires energy

Keq < 1

Answer 530

A

Insulin is secreted in response to high blood glucose levels by pancreatic beta cells.

Glucagon is secreted in response to low blood glucose levels from pancreatic alpha cells

Answer 531

A

the intestinal cells that produce Enzymes that digest disaccharides (including lactase)

Answer 532

A

includes the epiphyses (rounded ends covered by articular cartilage), the diaphysis (shaft containing the medullary cavity filled with yellow bone marrow), and the metaphysis (where the diaphysis and epiphyses meet).

periosteum is a thin layer of connective tissue that covers and protects long bones but does not cover joint surfaces.

Answer 533

A

Make up cellular component of cartilage

Answer 534

A

organized into concentric rings of bone matrix called lamellae. The entire unit of concentrically arranged lamellae surrounding a central haversian canal is known as an osteon, or a haversian system. Within each osteon, lacunae (spaces containing osteocytes) connect to one another via microscopic channels called canaliculi, which allow osteocyte waste exchange and nutrient delivery.

Answer 535

A

a firm but flexible connective tissue that lacks blood vessels and nerves. Chondrocytes (cartilage cells) secrete chondrin, which is the specialized extracellular matrix that makes up cartilage. The most common type of cartilage is hyaline cartilage, which lines the ends of articulating bones and plays a role in bone development.
Other types are elastic (flexible) and fibrous (limits movement)

Answer 536

A

When muscle contraction occurs, the myosin and actin filaments interact. Specifically, myosin heads bind to the actin filaments and slide them toward the central point of the sarcomere. This interaction shortens the sarcomere’s total length; however, the length of each actin and myosin filament remains unchanged. Instead, it is the sliding of the two filament types along one another that causes the sarcomere to shorten.
(I band and H band shorten)

Answer 537

A

osteocytes are surrounded by bone matrix and are located within spaces called lacunae in the Haversian system, they cannot travel to other cells during signaling.

Release signaling molecules responsible for stimulating other bone cells into canaliculi, the small canals that connect cells within the bone matrix. Signaling molecules released by osteocytes travel through these small canaliculi until they reach their target cells (ie, other bone cells).

Answer 538

A

chondrocytes (cartilage-producing cells) divide and produce collagen to which calcium phosphate attaches to form hardened bone. When chondrocytes in bone stop dividing, bone growth is complete.

Answer 539

A

a specialized endoplasmic reticulum in muscle fibers that is responsible for tightly regulating intracellular calcium concentration by sequestering calcium ions during periods of relaxation and releasing them into the cytosol during periods of contraction (in response to action potentials).

Answer 540

A

release of calcium from the SR promotes muscle fiber contraction whereas the transport of calcium into the SR promotes and maintains muscle fiber relaxation.

Answer 541

A

release of calcium from the SR promotes muscle fiber contraction whereas the transport of calcium into the SR promotes and maintains muscle fiber relaxation.

Answer 542

A

The arrival of an action potential at the axon terminal of the presynaptic motor neuron triggers release of ACh from presynaptic vesicles into the synaptic cleft via exocytosis. The ACh diffuses across the synaptic cleft to bind receptors embedded within the membrane of the postsynaptic muscle fiber, eventually leading to muscle contraction.

Answer 543

A

duodenum
jejunum
ileum

Answer 544

A

Esophagus is the tube through which ingested food, becomes a compact food mass (ie, bolus), and moves from the mouth, through the cardiac (lower esophageal) sphincter, and into the stomach.

Stomach is the sac in which the food bolus is chemically (ie, via stomach cell secretions) and mechanically digested, creating a semiliquid substance (ie, chyme) that moves through the pyloric sphincter into the small intestine.

Small intestine is the long, narrow tube consisting of three subdivisions (duodenum, jejunum, ileum) in which digestion of macromolecules is completed and the resulting useful substances are absorbed. Digestion of lipids in the small intestine is aided by bile, which is a nonenzymatic solution produced by liver cells and stored in the gallbladder. In addition, the pancreas secretes digestive enzymes into the small intestine along with bicarbonate, which assists in neutralizing the acidic chyme arriving from the stomach. Material unable to be digested passes to the large intestine through the ileocecal sphincter.

Large intestine is the wide tube consisting of three subdivisions (cecum, colon, rectum) in which water and electrolytes are absorbed from chyme to form solid feces.

Answer 545

A

reabsorbs water back into the circulation.

When the body is hydrated, the collecting ducts are less permeable to water and urine is less concentrated.
When body is dehydrated, the collecting ducts are more permeable to water and urine is more concentrated.

ADH stimulates the insertion of aquaporins into collecting duct cell membranes. This insertion increases collecting duct permeability to water, and by increasing water reabsorption decreases the amount of water in the urine (ie, the urine is more concentrated).

Answer 546

A

a layer of smooth muscle lining the bladder

Answer 547

A

the proximal sphincter muscle is known as the internal urethral sphincter (IUS). The IUS is composed of smooth muscle and is under involuntary control by the autonomic nervous system.

The distal sphincter, or the external urethral sphincter (EUS), is composed of skeletal muscle and is under voluntary control by the somatic nervous system.

Answer 548

A

All materials not filtered by the glomerulus exit via the efferent arterioles.

Answer 549

A

Activation of receptors on exocrine cells of the pancreas. Causes the pancreas to secrete proteolytic digestive enzymes (eg, trypsinogen, chymotrypsinogen) into the duodenum of the small intestine

Stimulation of gallbladder contraction. This causes the gallbladder to release its stores of nonenzymatic bile, which is originally produced by the liver

Increased the production of small lipid micelles in the small intestine. Bile released by the gallbladder, which contains bile salts, bile pigments (eg, bilirubin), and cholesterol, participates in the digestion of fats in the small intestine via emulsification. Specifically, bile salts have both a hydrophilic region that can associate with water and a hydrophobic region that can associate with the surface of lipids. This allows bile salts to act as detergents and break down large lipid globules into smaller droplets called micelles

Answer 550

A

A specialized division of the nervous system that innervates and regulates the function of the gastrointestinal tract. Functions may be modulated by the autonomic nervous system.

Answer 551

A

proteins synthesized by ribosomes on the rough endoplasmic reticulum are transported to the Golgi apparatus. In the Golgi apparatus, proteins are modified and packaged into vesicles to be transported to the cell membrane, used in organelles such as lysosomes, or secreted out of the cell.

Answer 552

A

large intestine includes
cecum (the absorption of large volumes of water and electrolytes, and the microbial digestion of soluble and insoluble carbohydrates before introduction to the ascending colon.)

colon (The colon functions to absorb electrolytes (eg, sodium, chloride) and additional water from the mass of undigested material)

rectum (responsible for storage of solid waste (feces) before it is eliminated from the body)

Answer 553

A

Decreases concentration of glucose in the blood

Answer 554

A

Proximal tubule: Bicarbonate (HCO3− ions, which can regulate blood pH, are reabsorbed along with other solutes and nutrients. Hydrogen ions (H+) and waste products are secreted into the filtrate.

Loop of Henle: The descending limb extending into the salty medulla reabsorbs water (H2O) via osmosis.
The ascending limb, which transports filtrate out of the medulla and back to the renal cortex, reabsorbs salts and potassium ions.

Distal tubule: Salts, H2O, and HCO3− are reabsorbed while potassium and H+ ions are secreted.

Collecting duct: H2O and salts continue to be reabsorbed, while potassium ions are secreted. In addition, to regulate blood pH, the reabsorption and secretion of HCO3− and H+ are regulated.

Answer 555

A

a multiorgan molecular cascade activated when BP (or blood volume) falls. A drop in BP causes the juxtaglomerular cells in the kidney to release renin, an enzyme that cleaves the plasma protein angiotensinogen to form angiotensin I. Angiotensin-converting enzyme then cleaves angiotensin I to form angiotensin II. Angiotensin II ultimately raises BP by inducing both the release of aldosterone from the adrenal cortex (increasing BP by increasing blood volume through water retention) and the constriction of arterioles (increasing BP without changing blood volume).

Answer 556

A

ADH promotes water reabsorption by increasing the permeability of the distal tubule and collecting duct to water.

Aldosterone promotes resoprtion of Na+ and secretion of K+; increased reabsorption of Na+ increases osmolarity/solute concentration of renal interstitial fluid which promotes water resorption.

Answer 557

A

flows from the kidney to the bladder through the ureter. Once the bladder is full, urine exits the body via the urethra through the process of urination. Urination is controlled by the detrusor muscle (smooth muscle lining the bladder), the internal urethral sphincter, and the external urethral sphincter.

Answer 558

A

fluid found in the tubules; pre urine/ will become urine

Answer 559

A

when substances go from interstitium to filtrate

Answer 560

A

when substances go from filtrate to interstitium

Answer 561

A

Primary (direct) active transport uses the energy released by ATP hydrolysis (performed by a transmembrane ATPase).

Secondary (indirect) active transport is a coupled transport process that uses the energy released by the movement of one substance along its concentration gradient (passive transport) to move another substance against its concentration gradient. Essentially, the potential energy stored in the concentration gradient of one molecule is used for the transport of another molecule.

Answer 562

A

Bile is synthesized in the liver, stored in the gallbladder, and released into the duodenum to aid lipid digestion. Bile salts, a key component of bile, mechanically digest lipid globules by physically breaking them down into smaller droplets in a process known as emulsification. Subsequently, pancreatic lipase chemically digests emulsified lipids.

Answer 563

A

a muscular ring located at the junction of the stomach and the duodenum; this sphincter controls the flow of chyme, or partially digested food, from the stomach into the duodenum.

Answer 564

A

intrinsic factor (from parietal cells), which aids in the absorption of vitamin B12

pepsinogen (from chief cells), which cleaves polypeptides when activated by HCl

mucus (from mucous cells) and bicarbonate (from epithelial cells), which protect the stomach lining against autodigestion by gastric juice.

Answer 565

A

peritoneum comprises two membranes that line the abdomen: the parietal layer, which lines the abdominal wall, and the visceral layer, which covers the abdominal organs.

The peritoneal cavity is a potential space between the parietal and visceral layers of the peritoneum.

Answer 566

A

cold temperatures
secretion of renin ( to increase bp )
loss of blood

Answer 567

A

Blood first enters arteries, become progressively smaller in diameter until they branch into arterioles.
Arterioles deliver blood to the capillaries (smallest blood vessels) of the lungs. Gas exchange occurs across these capillaries: deoxygenated blood in the capillaries expels CO2 to the alveolar spaces (air sacs), which will be exhaled from the body. The blood in turn receives O2 from the alveolar spaces (ie, becomes reoxygenated).
From the lung capillaries, freshly oxygenated blood enters the smallest veins (vessels that carry blood toward the heart), known as venules.
Venules become progressively larger veins (ie, pulmonary veins), which are low-pressure vessels that will ultimately deliver blood to the left atrium of the heart.

Answer 568

A

Hemoglobin consists of four subunits, each of which can exist in either of two conformations: the T state (“tense,” low oxygen affinity; O2 not bound) or the R state (“relaxed,” high oxygen affinity; O2 bound).

Answer 569

A

Accumulated H+ ions can bind to hemoglobin and reduce its affinity for oxygen

during exercise, will experience increase in H+ in the blood. The reduction in hemoglobin affinity for oxygen allows more O2 to be unloaded to the muscle cells. Therefore, the need for more oxygen in contracting muscles is met because the byproducts generated during exercise decrease hemoglobin-oxygen binding.

Answer 570

A

Bisphosphoglycerate mutase converts 1,3-bisphosphoglycerate into 2,3-bisphosphoglycerate, which allosterically regulates hemoglobin. It decreases oxygen affinity by stabilizing the deoxyhemoglobin conformation. Increasing concentrations of 2,3-bisphosphoglycerate produce a right shift in the oxyhemoglobin dissociation curve and favor oxygen delivery to tissues.

Answer 571

A

CO2 and H+ allosterically decrease the affinity of hemoglobin for oxygen, so their removal will increase the affinity and result in less delivery of oxygen to tissues as hemoglobin fails to release it.

Answer 572

A

The excessive exhalation depletes blood CO2. Carbon dioxide is in equilibrium with carbonic acid (H2CO3), which in turn is in equilibrium with bicarbonate (HCO3−) in the blood.

This equilibrium forms the basis for the bicarbonate buffering system, which helps control blood pH. As CO2 is removed, the equilibrium shifts to favor production of more CO2 via the consumption of carbonic acid and bicarbonate, which increases blood pH (fewer H+ ions).

Answer 573

A

a standard laboratory measurement of red blood cell volume as a percentage of total blood volume. It indicates the amount of intact red blood cells within a blood sample.

Answer 574

A

a measure of the rate at which fluid is filtered into the Bowman capsule from the glomerulus.

GFR is proportional to the hydrostatic (blood) pressure within the glomerulus. As such, GFR can be expected to decrease if the afferent arterioles constrict (ie, because less blood enters the glomerulus) or the efferent arterioles dilate (ie, because more blood exits the glomerulus).

Answer 575

A

Heart rate is regulated by the activity of specialized clusters of self-depolarizing cells known as the SA and AV nodes. APs are initiated in the SA node and travel through the atria, stimulating atrial contraction. These APs then reach the AV node and, after a brief delay, are relayed to ventricular cells, stimulating ventricular contraction.

Answer 576

A

make up the endothelium, or the interior lining of the heart and blood vessels, which are the components of the cardiovascular system

are in direct contact with blood and the surrounding matrix so these are the cells that play the most important role in gas exchange.

Answer 577

A

At rest, extended heads of the myosin filaments exist in an upright (high-energy) conformation bound to ADP and Pi, whereas actin filaments are bound to two regulatory proteins, troponin and tropomyosin. Troponin is a small protein complex associated with tropomyosin, an elongated protein wrapped around the actin filament that blocks the myosin binding sites while the sarcomere is at rest.

Depolarization of cardiac muscle cells triggers the release of calcium ions from the sarcoplasmic reticulum and from the extracellular fluid into the cytosol. Calcium ions bind troponin, causing a conformational change to tropomyosin described by the sliding filament model.

This conformational change exposes the myosin binding sites on the actin filaments, allowing myosin heads to bind the actin filament, forming a cross-bridge. This promotes the release of ADP and Pi from myosin, which in turn changes to the low-energy conformation.

These changes cause a power stroke, which acts to drag the actin filament toward the center of the sarcomere.

Following the power stroke, a new ATP molecule binds myosin, leading to cross-bridge disassembly.

Hydrolysis of this ATP returns the myosin head to its high-energy conformation for the next contraction cycle.

Answer 578

A

A negative ΔG° indicates that products are favored, whereas a positive ΔG° indicates that reactants are favored.

Answer 579

A

cofactors that are tightly bound

Answer 580

A

measures the frequency of hydrogen nuclei spinning in a magnetic field. This frequency, referred to as the chemical shift, is measured in ppm and describes the electron density surrounding a proton within a molecule.
When surrounded by high electron density, protons are said to be “shielded” from the magnetic field. However, electronegative atoms draw electron density from nearby protons, causing them to become deshielded.

Protons that are shielded appear to the right (upfield) of the NMR spectrum whereas deshielded protons appear to the left (downfield).

Answer 581

A

lactate, pyruvate, and glycerol
and most amino acids

Answer 582

A

is induced when cytochrome C is allowed to leave the mitochondria and enter the cytosol, where it activates caspase. Caspase in turn activates several degradative pathways such as proteolysis.

Answer 583

A

an anabolic process that builds lipids in the cytosol. Anabolic processes generally require energy, reducing power, and sufficient precursor molecules– for FA synthesis: ATP, NADPH, and acetyl-CoA, respectively.

During fatty acid synthesis, NADPH is oxidized to NADP+ to reduce the carbonyl groups and subsequent carbon-carbon double bonds on each acetyl-CoA molecule added to the fatty acid chain. If fatty acid synthesis is inhibited, the conversion of NADPH to NADP+ will occur less frequently, and cytosolic NADPH will build up.

Answer 584

A

generate α-keto acids from amino acids by transferring the −NH3+ group to α-ketoglutarate, which is converted to glutamate.

Answer 585

A

In the absence of oxygen, pyruvate is reduced to lactate to regenerate NAD+ during fermentation.

Answer 586

A

Isocitrate dehydrogenase
Alpha- Ketoglutarate
Malate Dehydrogenase

Answer 587

A

Succinate dehydrogenase

Answer 588

A

Succinyl CoA Synthetase

Answer 589

A

helps regulate fatty acid metabolism by inhibiting long-chain fatty acid transport into the mitochondria. Processes that decrease malonyl-CoA levels are likely to increase fatty acid transport to the mitochondria and, as a result, increase beta oxidation.

When it’s decreased, fatty acid transport is increased and so is beta oxidation

Answer 590

A

includes the conversion of pyruvate to oxaloacetate and the use of phosphatases such as G6Pase instead of kinases to remove phosphate groups

Answer 591

A

required for nucleotide and NADPH synthesis.

Answer 592

A

NAD+ is reduced to NADH

Answer 593

A

the synthesis of NAD+ from NADH

Answer 594

A

Amino acids (except for leucine and lysine) can be converted into glucose through gluconeogenesis.

Answer 595

A

Glycogen phosphorylase catalyzes the release of glucose residues from linear glycogen segments

Debranching enzyme linearizes branched segments of glycogen for subsequent degradation by phosphorylase.

Answer 596

A

Electrons flow from cytochromes with low to high reduction potential

Because reduction potential indicates an oxidized molecule’s affinity for electrons, electrons are transferred from species with lower reduction potentials (ie, less affinity for electrons) to species with higher reduction potentials (ie, more affinity for electrons) throughout the chain.

Answer 597

A

target defective or unnecessary proteins for destruction by the proteasome.

Answer 598

A

added to certain asparagine residues of proteins in the endoplasmic reticulum.

Answer 599

A

transamination, during which the amino group is transferred to α-ketoglutarate, forming glutamate and the α-keto acid

Answer 600

A

electron transport chain

ATP synthase

Answer 601

A

proton concentration is higher outside than inside the mitochondrial matrix, producing an electrochemical potential across the membrane

Answer 602

A

isocitrate and α-ketoglutarate as substrates

If these are inhibited, reaction will favor the reactants

Answer 603

A

a flavoprotein (an oxidoreductase that contains an FAD or FMN prosthetic group) that is also known as succinate dehydrogenase.
It is part of both the ETC and the citric acid cycle.

In Complex II, electrons are transferred from succinate to an FAD molecule that is covalently attached to the protein complex, producing fumarate and FADH2. The FADH2 then transfers its electrons to ubiquinone, forming ubiquinol and regenerating FAD.

Answer 604

A

facilitates proper protein folding and inhibits the formation of nonfunctional protein aggregates

Answer 605

A

functions in formation of vesicles for intracellar trafficking

Answer 606

A

the mature RNA sequence for a protein that is secreted or that will locate to the cell membrane will contain the signal sequence. This portion of the mRNA is located in the 5′ region and will signal to the ribosome that translation needs to be continued in the rough endoplasmic reticulum.

Answer 607

A

During glycolysis NAD+ is reduced to form NADH.

During the citric acid cycle, NAD+ is reduced to form NADH.

During the electron transport chain, NADH is oxidized to form NAD+.

Chemiosmosis is the only step of cellular respiration where NAD+ is neither reduced to form NADH, nor is NADH oxidized to form NAD+.

Answer 608

A

A single ring can be found in a monoterpene.

An indole has two fused rings.

A steroid is composed of a 6-6-6-5 fused ring assembly, which is a total of 4 fused rings.

Answer 609

A

An increase in the threshold would make it more challenging for a neuron to fire an action potential. This will reduce the frequency of downstream neuron depolarizations, resulting in relief of the symptoms.

An increase in the concentration of Na+ outside the cell will not help reduce the symptoms, because there will still be a flux of ions inside the cell when the firing starts, causing continuous depolarization.

Anion influx hyperpolarizes a neuron, reducing likelihood of action potential firing. Therefore, a decrease in axonal-membrane permeability to negative ions will not provide a relief as it will increase action potential firing.

A decrease in length of the depolarization stage will allow for a higher frequency of action potential firing. This would worsen the situation instead of improving it.

Answer 610

A

the first tubule where the glomerular filtrate passes through. About 65% of the glomerular filtrate is reabsorbed in the proximal collecting tubule.

In contrast, the distal tubule contains relatively dilute glomerular filtrate.

Answer 611

A

the last portion of the tubules where reabsorption of water and salts can occur, which concentrates filtrate.

The glomerular filtrate is, slightly less concentrated in the cortical portion of the collecting duct than in the medullary portion.
The medullary portion of the collecting duct is the last portion of the tubules where reabsorption can occur. In the portion of the tubule that follows, there will be no more reabsorption. Thus, the medullary portion of the collecting duct contains the most concentrated glomerular filtrate that will correspond to the urine.

Answer 612

A

Free energy does not correlate with enzyme activity because it is NOT a measure of reaction rate/activity

Answer 613

A

Na+/K+ ATPase. This is achieved by moving three Na+ out of the cell for every two K+ ions that are brought into the cell (against their concentration gradient).

Answer 614

A

the release of a neurotransmitter that binds to ligand gated channels

Answer 615

A

Simple diffusion

Answer 616

A

Occurs passively due to a pressure difference;

three pressures that work together to regulate filtration in the glomerulus: glomerular capillary pressure, capsular hydrostatic pressure, and blood colloid osmotic pressure.

The glomerular capillary pressure will force filtrate from a capillary into Bowman’s capsule; the other two forces promote movement of the filtrate in the opposite direction.

Answer 617

A

co localize substrates

alter the pH

alter substrate shape

Answer 618

A

mRNA triplets are read by ribosomes, and tRNA molecules provide the amino acids.
Each amino acid is matched to a tRNA molecule carrying a specific anti-codon.
A specific amino acid will be added if it is recognized by its specific codon.

Answer 619

A

allows you to link the nucleotide sequence to an amino acid

contains an amino acid and an anti-codon which helps identify correct codon

has clover shape with three loops

connects to ribosome which has A site (binding), P site (peptide bond will pass through), E site (exit)

Answer 620

A

from negative feedback;

high levels of circulating glucose and other stressors activate the production of corticotropin-releasing hormone (CRH) from the hypothalamus. CRH will stimulate the pituitary gland to release ACTH which will trigger cortisol release from the adrenal cortex.

The presence of high levels of circulating cortisol will inhibit CRH secretion (negative feedback) thus closing the loop.

Answer 621

A

hypothalamus controls release of hormones from pituitary gland; from pituitary gland, hormones are released into the blood stream and travel to kidneys and influence secretion of hormones from adrenal glands

hypothalamus releases CRH which causes ACTH to be released, which then prompts release of cortisol– when cortisol is high, negative feedback causes the HPA to shut off (no more CRH secretion)

in addisons disease, there is low circulating cortisol, so the feedback loop will never shut off and crh will continue to release acth

Answer 622

A

Suppress immune function and degrade proteins

High levels of circulating glucocorticoids will increase protein degradation in various tissues, could cause muscle weakness

Answer 623

A

decrease the cellular concentration of glucose. To compensate for the low cellular glucose concentration, glucose uptake is increased.

Answer 624

A

endomembrane system is the portion of the cells that is in charge of modifying proteins that will be secreted.

Answer 625

A

their appetite may increase

may also experience sweet tasting urine due to excess glucose in the filtrate, weight loss, or fatigue

Answer 626

A

do FOIL method on the genotypes then make a large square with 16 squares

Answer 627

A

500; Each amino acid is coded by a triplet of nucleobases. Thus, 1500/ 3 = 500 amino acids

bases/ 3 = aas

aas x 3 = bases

Answer 628

A

Norepinephrine and epinephrine are released by the adrenal medulla and modulate the metabolism of glycogen, the storage form of glucose.

Both promote glycogenolysis (glycogen to glucose). By inhibiting the enzymes that mediate glycogen synthesis, norepinephrine and epinephrine also inhibit glycogenesis (formation of glycogen from glucose).
inhibit energy storage

Answer 629

A

Glucocorticoids (eg, cortisol) released by the adrenal cortex act on the liver to stimulate the synthesis of glucose from other molecules (ie, gluconeogenesis) and the breakdown of fats into fatty acids (ie, lipolysis). Glucose and free fatty acids are forms of cellular energy that can be readily utilized.

promote energy utilization

Answer 630

A

smooth ER

Answer 631

A

ADH causes the insertion of aquaporins (water channels) in the collecting duct, which increases water permeability and reabsorption, and ultimately increases blood volume and blood pressure.

Answer 632

A

ADH concentration in the blood is inversely related to blood volume, all other factors being equal. This relationship is consistent with the role of ADH to stimulate water retention and means that ADH release should be suppressed during blood volume expansion to allow more water excretion in urine. Therefore, blood ADH concentration would be expected to be significantly lower when blood volume is high

Answer 633

A

Less

ADH is secreted in response to reductions in blood volume or osmolarity. This secretion causes increased water reabsorption in the collecting duct, therefore producing less urineexocrine glands secrete substances into a ductal system to an epithelial surface, endocrine glands secrete products directly into the bloodstream

Answer 634

A

exocrine glands secrete substances into a ductal system to an epithelial surface, endocrine glands secrete products directly into the bloodstream

Answer 635

A

glucagon and epinephrine (stimulates glucagon release)

Answer 636

A

It is synthesized in the liver, muscle

triglyceride synthesis (via glucose transport into adipocytes), and protein synthesis (via entry of plasma amino acids into tissues) will also occur when insulin is released

Answer 637

A

Glucagon increases blood glucose levels by promoting production of gluconeogenic substrates and by stimulating glycogen breakdown (glycogenolysis) and hepatic gluconeogenesis (convert glycogen back into glucose)

Answer 638

A

by binding its stimulatory G protein–coupled receptor on the cell membrane and inducing the adenylate cyclase/cAMP second messenger cascade.

In the G protein–regulated cAMP signaling pathway, a ligand binds the transmembrane G protein–coupled receptor and activates the GDP-bound alpha subunit of the G protein by replacing GDP with GTP. The activated G alpha subunit activates the enzyme adenylate cyclase, which catalyzes the conversion of ATP into cAMP. Elevated cAMP leads to the activation of protein kinase A and subsequent signaling effects.

Answer 639

A

leptin is released by white adipocytes to trigger appetite suppression via the hypothalamus.

Answer 640

A

released by stomach gastric cells to trigger hunger and food-seeking behavior via the hypothalamus.

Answer 641

A

In response to low thyroid hormone levels or a decrease in body temperature, the hypothalamus secretes thyrotropin-releasing hormone (TRH).

TRH acts on the anterior pituitary, which causes the release of thyroid-stimulating hormone (TSH).

TSH binds to TSH receptors on cells of the thyroid gland, stimulating these cells to release thyroid hormones.

Upon stimulation by TSH, thyroid gland cells secrete two types of thyroid hormones: triiodothyronine (T3) and thyroxine (T4). When released, T3 and T4 affect nearly every cell in the body by increasing cellular metabolism. These hormones also function in a negative feedback loop by inhibiting the secretion of TRH and TSH.

Answer 642

A

show brain activity in varying psychological states (alert vs. drowsy etc.)

place electrodes on the scalp then get their electric potential

Answer 643

A

Thyroid hormones are hormones released by the thyroid gland when it is stimulated by thyroid-stimulating hormone. Thyroid hormones affect the body by increasing cellular metabolism.

Answer 644

A

Thyroid hormones are hormones released by the thyroid gland when it is stimulated by thyroid-stimulating hormone. Thyroid hormones affect the body by increasing cellular metabolism.

Answer 645

A

Thyroid hormones are hormones released by the thyroid gland when it is stimulated by thyroid-stimulating hormone. Thyroid hormones affect the body by increasing cellular metabolism.

Answer 646

A

A DNA molecule consisting of thymine repeats– thymine could pair with adenine of poly A tail which is unique to mRNA

Answer 647

A

In eukaryotic cells, the nucleolus is within the nucleus and is the primary site of ribosomal RNA (rRNA) transcription by RNA polymerase I.

Ribosomal proteins are synthesized in the cytoplasm from mRNA and transported into the nucleolus, where they combine with the newly transcribed rRNA to form precursors to the 40S and 60S subunits. These subunits are then shuttled out of the nucleus via nuclear pores and fully mature in the cytoplasm.

Answer 648

A

Histone proteins are rich in positively charged arginine and lysine, which facilitate binding to negatively charged DNA.

Answer 649

A

heterochromatin, a transcriptionally inactive and tightly condensed complex of DNA wrapped around histones.

Centromeres join two sister chromatids and are essential for proper chromosome division during mitosis. Telomeres are regions at the chromosome ends that are repeatedly truncated each time a cell divides.

Answer 650

A

water, electrolytes, gases, hormones, nutrients, metabolic waste, and proteins (eg, albumin).

Answer 651

A

Just change the Us to Ts– this should be an identical strand otherwise

Answer 652

A

mitochondria

Answer 653

A

Replication

Answer 654

A

band intensity denotes quantity of mRNA expression and band location denotes size (ie, smaller molecules appear lower than larger ones).

Answer 655

A

The isoelectric point (pI) of a protein is the pH at which the protein has a net charge of zero. The more positively charged the protein is at physiological pH, the higher its pI.

Answer 656

A

RNA structures such as hairpin loops are stabilized by hydrogen bonds between base pairs. G-C base pairs form more hydrogen bonds than A-U base pairs. Therefore, structures with more total base pairs and more G-C base pairs are more stable.

Answer 657

A

Testes: reproductive glands that produce sperm during spermatogenesis.

Epididymis: a long, tightly coiled tube on the posterior of each testis; immobile sperm produced by the testes become mature and motile within this tube. Mature sperm are stored in the epididymis until release

Ductus (vas) deferens: a long, muscular tube that transfers mature sperm to the urethra

Seminal glands: accessory glands that produce the largest portion of seminal fluid

Prostate: a gland that produces prostatic fluid containing enzymes necessary to prevent the coagulation of sperm in the vagina.

Bulbourethral (Cowper’s) glands: glands that secrete thick, alkaline mucus to lubricate the tip of the penis. The alkalinity of the mucus neutralizes acids in the urine to protect the sperm from the acidic environment of the urethra.

Penis: an exterior organ that functions in sexual intercourse by which ejaculation of semen (mixture of sperm and seminal fluid) occurs.

Answer 658

A

Totipotent stem cells are the least specialized cells and can give rise to both placental and fetal cells.

Pluripotent stem cells can give rise to only fetal cells (ie, all cell lineages from the three germ layers).

Multipotent cells are able to differentiate only into the specialized cells of certain tissues; these cells are also found in adults.

Answer 659

A

signaling molecules whose CONCENTRATIONS influence cell differentiation; alter gene expression in competent cells

Answer 660

A

Inbreeding results in decreased heterozygosity (genetic diversity), reduced fecundity, and reduced fitness.

Species that mate with nonrelatives (outbreed) increase their fitness because the introduction of new genetic material results in increased heterozygosity.

Answer 661

A

the process of diversifying characteristics (eg, claw and teeth size) to better fill an ecological niche.

Adaptive radiation can eventually lead to speciation if the subgroup continues to diverge and loses the ability to interbreed with individuals from the original species.

Answer 662

A

results in the selection of 2 extreme phenotypes that differ from the average. In disruptive selection, the average phenotype is selected against while 2 extreme phenotypes are selected for.

Answer 663

A

phenotypes are narrowed toward an average, homogeneous phenotype by selecting against extreme phenotypes; as a consequence, diversity is decreased within the population.

Answer 664

A

pregnancy hormone; maintains corpus luteum and secretes progesterone

Answer 665

A

a glycerol backbone linked to a phosphate group and two fatty acids

Answer 666

A

Glycolysis breaks down glucose into pyruvate in a series of reactions that generate ATP and reduce NAD+ to NADH. NAD+ must be regenerated for glycolysis to continue, and this process can occur either in the mitochondria (electron transport chain) or in the cytosol (fermentation).

Red blood cells lack mitochondria, and can regenerate NAD+ only by fermentation. Fermentation occurs when lactate dehydrogenase catalyzes the reduction of pyruvate to lactate. The required electrons are provided by the oxidation of NADH to form NAD+.

Answer 667

A

it is the point where the substrate is at 1/2 Vmax; the x-axis value here is equal to the Km value

Answer 668

A

Catalytic efficiency is the ratio of kcat to the Michaelis constant Km. Both are intrinsic properties of the enzyme and are not altered by a change in enzyme concentration.

Catalytic turnover kcat is an intrinsic property of the enzyme and is not altered by a change in enzyme concentration.

Answer 669

A

No, the tertiary carbon does not have any C-H bonds to lose

Answer 670

A

It becomes a carboxylic acid

Answer 671

A

It becomes a ketone

Answer 672

A

the tendency of alleles in close proximity to remain on the same chromosome and be inherited together by offspring. This tendency occurs because of fewer crossover events between these loci during meiosis, resulting in a greater number of haploid gametes with nonrecombinant genotypes.

Answer 673

A

agents that promote genetic mutations or increase their frequency; can decrease molecules required for viral replication

Answer 674

A

No, since they are XY, if they have it, they will express it

Answer 675

A

PEP to pyruvate w/ pyruvate kinase

F6P to F1,6BP w/ PFK-1

Answer 676

A

Complex I receives a pair of electrons from NADH. The electrons are passed through a series of intermediate redox centers within the complex before reducing ubiquinone to ubiquinol.

Complex II receives a pair of electrons from FADH2. Like Complex I, the electrons ultimately reduce ubiquinone to ubiquinol.

Complex III receives electrons from the ubiquinol produced by either Complex I or Complex II and ultimately transfers them to cytochrome c (cyt c). For every pair of electrons received, two cyt c are reduced.

Complex IV receives electrons from cyt c and transfers them to molecular oxygen (O2). Four electrons are needed to fully reduce a molecule of oxygen, so the stoichiometry per reduced cofactor (ie, NADH or FADH2) is two electrons reduce half a molecule of O2, producing one molecule of H2O.

Answer 677

A

Complex I receives a pair of electrons from NADH. The electrons are passed through a series of intermediate redox centers within the complex before reducing ubiquinone to ubiquinol.

Complex II receives a pair of electrons from FADH2. Like Complex I, the electrons ultimately reduce ubiquinone to ubiquinol.

Complex III receives electrons from the ubiquinol produced by either Complex I or Complex II and ultimately transfers them to cytochrome c (cyt c). For every pair of electrons received, two cyt c are reduced.

Complex IV receives electrons from cyt c and transfers them to molecular oxygen (O2). Four electrons are needed to fully reduce a molecule of oxygen, so the stoichiometry per reduced cofactor (ie, NADH or FADH2) is two electrons reduce half a molecule of O2, producing one molecule of H2O.

Answer 678

A

The pentose phosphate pathway (PPP) can produce ribose 5-phosphate by decarboxylation of glucose 6-phosphate (oxidative phase)

or by rearranging the carbon atoms in fructose 6-phosphate (F6P) and glyceraldehyde 3-phosphate (nonoxidative phase). F6P can be converted to all these intermediates by the enzymes of glycolysis and the PPP.

Answer 679

A

epinephrine binds to G protein–coupled receptors, which activates glycogen phosphorylase.

G protein–coupled receptors activate adenylate cyclase + convert ATP into cyclic AMP (cAMP) in the cytosol. cAMP then allosterically activates protein kinase A, initiating a phosphorylation cascade that activates glycogen phosphorylase, the first enzyme in glycogenolysis.

Answer 680

A

Glycogen is degraded by phosphorolysis, or the addition of phosphate to break a bond, to produce glucose 1-phosphate (G1P). G1P is subsequently transformed into glucose 6-phosphate for use in glycolysis or the pentose phosphate pathway.

Answer 681

A

alpha- ketoglutarate is a nitrogen acceptor; it is disposed of in the urea cycle (in liver)

glutamate however is a nitrogen donor

Answer 682

A

yes, but beta oxidation must occur first– lose acetyl coa and form reduced cofactors

Answer 683

A

no, it is irreversible

Answer 684

A

hydrolyze ester linkages to form free fatty acids to then be put through beta oxidation

in beta oxidation, will create acetyl coa

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