Bio/Biochem Review

Question 1

How do catalyts and inhibitors affect reaction rates?

How is ∆G affected by enzymes?

Answer 1

Catalysts increase the reaction rate, inhibitors decrease the reaction rate

∆G is not affected by enzymes

Question 2

Name the cellular location and end products (per glucose) for the following:

Glycolysis, pyruvate dehydrogenase complex, Krebs cycle, electron transport, fermentation

Answer 2

Glycolysis: Cytoplasm, 2 NADH, 2 pyruvate, 2 ATP (net)

PDC: Mitochondrial matrix, 2 NADH, 2 acetyl-CoA and 2 CO₂

Krebs Cycle: Mitochondrial matrix, 6 NADH, 2 FADH, 2 GTP, 4 CO₂

Electron Transport Chain: Inner mitochondrial membrane, end product is a proton gradient (30 ATP generated)

Fermentation: Cytoplasm, end products are 2 ATP, 2 lactic acid (muscle) or 2 ethanol (yeast)

Question 3

Name the cellular location and main products of the following biochemical pathways:

Gluconeogenesis, glycogenesis, glycogenolysis, fatty acid oxidation, fatty acid synthesis, and the pentose phosphate pathway

Answer 3

All reactions occur in the cytosol besides fatty acid oxidation, which occurs in the mitochondrial matrix

Gluconeogenesis - Glucose-6-phosphate

Glycogenesis - glycogen

Glycogenolysis - Glucose-1-phosphate

Fatty acid oxidation - Acetyl-CoA units

Fatty acid synthesis - 16-C fatty acid (palmitate)

Pentose phosphate pathway - NADPH (oxidative) ribulose-5-phosphate (non-oxidative)

Question 4

Define replication, transcription, and translation. At which stage is protein synthesis primarily regulated?

Answer 4

Replication = DNA to DNA

Transcription = DNA to RNA

Translation = RNA into protein

Regulation of protein synthesis if primarily at the level of transcription.

Question 5

What does semiconservative replication mean?

Answer 5

After DNA replication, one strand of a DNA double helix is composed of old DNA and the other is composed of newly-synthesized DNA

Question 6

What are the differences between DNA and RNA?

Name 3 types of RNA and their functions

Answer 6

DNA is double stranded, thymine, sugar is deoxyribose

RNA is single stranded, uracil, sugar is ribose

mRNA = translated to make proteins

rRNA = needed to make a functional ribosome (Without, cell can’t make proteins, and cell function will be inhibited)

tRNA = carries an amino acid to a ribosome to be incorportated into a growing protein

Question 7

Name at least 5 differences between prokaryotes and eukaryotes

Answer 7

Prokaryotes don’t have a nucleus or organelles, have a single circular chromosome, 3 different DNA polymerases and 1 RNA polymerase. Transcription and translation are simultaneous, their mRNA is polycistronic, and there is no mRNA processing

Eukaryotes have a nucleus and other organelles, have several linear chromosomes, 1 DNA polymerase and 3 different RNA polymerases. mRNA is monocistronic, and mRNA must be processed before translation.

Question 8

What is the basic structure of a virus?

Answer 8

A virus is a piece of nucleic acid surrounded by a protein shell (capsid)

Viruses are obligate parasites

Question 9

Name three different life cycles of a virus. Which of these is of an animal virus life cycle only?

Answer 9

Lytic, lysogenic, productive

Productive is for animal viruses only

Question 10

What is a prion? What is a viroid?

Answer 10

A prion is an abnormally folded version of a normal protein that is able to convert other prions to its abnormal form. (Infectious protein)

They are highly resistant to degradation by heat, acids, etc and are implicated in degenerative brain disorders

Viroids are short, single stranded RNAs that have highly complimentary sequences. They are plant pathogens that are though to affect protein synthesis by binding and silencing normal cellular RNAs.

Question 11

Name the 3 shapes of bacteria

Answer 11

Coccus (round)

Bacillus (Rod-shaped) (E. Coli is a gram negative bacillus)

Spiral (Spirochete)

Question 12

Define obligate aerobe, facultative anaerobe, tolerant anaerobe, and obligate anaerobe

Answer 12

Obligate aerobe - must use oxygen to survive

Facultative anaerobe - prefers oxygen, but will ferment to survive

Tolerant anaerobe - can tolerate oxygen, but ferments to survive

Obligate anaerobe - will die in the presence of oxygen

Question 13

Name the cell organelles and their functions

Answer 13

Nucleus = control center, contains DNA and is the site of replication and transcription

Ribosome = protein synthesis

Rough ER = holds ribosomes that are synthesizing secreted or membrane proteins, functions in protein modification

Golgi apparatus = sorts and packages proteins, protein modification

Lysosome = digestive enzyme container

Mitochondria = energy production

Smooth ER = lipid metabolism

Centrosome = mitotic spindle formation

Peroxisome = eliminated free radicals

Question 14

What are the four main colligative properties?

What do they depend on?

Answer 14

Vapor-pressure depression, boiling point elevation, freezing-point depression, and osmotic pressure.

They depend only on the number of solute particles in a solution and not on the type of particle

Question 15

What is the difference between osmosis and diffusion?

What is the van’t Hoff factor?

Answer 15

Osmosis is the movement of water from an area of low solute concentration to an area of high solute concentration

Diffusion is the movement of solute from an area of high solute concentration to an area of low solute concentration

The van’t Hoff factor is the ionizability factor, it tells how many ions one unit of substance will produce in solution

Question 16

What types of molecules can easily cross the plasma membrane? Which cannot?

Answer 16

Small, nonpolar molecules can easily cross the plasma membrane (Oxygen, CO2)

Large, and/or polar molecules cannot

Question 17

What is an oncogene?

What is a tumor supressor gene?

Answer 17

An oncogene is a mutated proto-oncogene that are permanately active.

Proto-oncogenes regulate the cell cycle, and activate it during times of development, growth, or healing.

The cell cycle is permanently on, and cell growth and division occurs without control. Gain of function mutation

Tumor suppressor genes code for proteins to slow or stop the cell cycle until DNA damage is repaired. If DNA is not repairable, they trigger apoptosis. Loss of function mutation

Question 18

Name the stages of mitosis and describe the location of the chromosomes in each.

What is the end product of mitosis?

Where is there heavy regulation?

What is the difference between mitosis and meiosis?

Answer 18

Prophase = replicated chromosomes condense in a deteriorating nucleus (Build spindle, condense DNA, break down nuclear membrane)

Metaphase = chromosomes randomly align at the cell center

Anaphase = separate sister chromatids by pulling at the centromeres (Cytokinesis begins)

Telophase = Reverse prophase. Decondense DNA, break down the spindle, and rebuild the nuclear membrane. Finish cytokinesis

DNA replication occurs during the S phase of interphase

The end product of mitosis is two daughter cells that are identical to each other and identical to the parent cell

There is heavy regulation at the G1-S phase, because the cell isn’t going to replicate if it doesn’t need to.

Mitosis is the division of s**omatic (body) cells, meiosis is the division of gametes (germ cells)

Question 19

Name the stages of meiosis and describe the location of the chromosomes in each.

When is the cell considered to be haploid?

What is the end result of meiosis?

Answer 19

Prophase I - Build spindle, condense DNA, break down nuclear membrane (Synapsis - pairing of homologous chromosomes/Crossing over occurs - DNA exchange) (Specific) *Longest phase of meiosis

Metaphase I - Tetrads randomly align at the cell center. (In mitosis it would be individual chromosomes)

Anaphase I - separate homologs partners, pulled to opposite sides of the cell. Begin cytokinesis

Telophase I - New nucleus forms. (Possibly reverse mitotic prophase)and finish cytokinesis

Prophase II, metaphase II, anaphase II, and telophase II = chromosome movements are identical to movements during mitosis, but the amount of DNA is reduced by half. (starting with less)

Cell is haploid after telophase I

Is diploid during G1 and G2

4 cells that are very different from each other and from the parent cell

Question 20

Define gene, traitr, allele, genotype, and phenotype

Answer 20

Gene = piece of DNA that codes for some product

Trait = physical characteristic of an organism

Allele = version of a gene

Genotype = combination of alleles an organism has

Phenotype = physical characteristics of an organism dictates by alleles

Question 21

State the rules of multiplication and addition.

How can they be used?

Answer 21

Rule of multiplication: probability of A and B = (Prob A) x (Prob B)

Rule of addition - Probability of A or B = (Prob A) + (Prob B) - (Prob A and B)

These are used to solve genetic probability problems by reducing them to a series of simple single gene crosses, the results of which can be combined using the rules.

Question 22

What are the outcomes of the four basic single gene crosses?

Answer 22

1. Homozygote x Homozygote = 100% same homozygote
2. Homozygous dominant x homozygouse recessive = 100% heterozygote
3. Homozygote x heterozygote = 50% same homozygote, 50% heterozygote
4. Heterozygote x Heterozygote = 25% homozygous dominant, 50% heterozygotes + 25% homozygous recessive

Question 23

Name two ways to determine whether genes are linked

Answer 23

If after a cross involving two different genes, the progeny do not match what would be expected ratios for unlinked genes. (The alleles don’t sort independently)

RF value < 50%

Recombination frequency = # recombinants/total progeny x 100

Question 24

What are the two Hardy Weinberg equations?

What are the 5 conditions for these equations

Answer 24

Allele frequency: p + q = 1

Genotype frequency: p² + 2pq + q² = 1

Large population, random mating, no migration, no mutations, no natural selection

Question 25

What is the basic theory behind evolution by natural selection?

Answer 25

Organisms that are better adapts to an environment will survive better than organisms that are poorly adapted. Because they survive, genes will be passed on to their offspring. Over time, this can substantially alter a population.

Question 26

Describe the basic structure of a neuron

Answer 26

Dendrites send impulses toward the cell body, and axons send impulses away from the cell body

Question 27

Define depolarize, hyperpolarize, and repolarize. What ion channels control the action potential?

Answer 27

Depolarize = move away from rest potential in the positive direction

Hyperpolarize = move away from rest potential in the negative direction

Repolarize = return to rest potential

Voltage gated sodium (depolarize) and voltage gated potassium channels (hyperpolarize/repolarize) control the action potential.

Question 28

Differentiate between the sympathetic and parasympathetic NS. Which system is the adrenal medulla part of?

Answer 28

Sympathetic = fright, fight, flight, and sex - speeds up body processes

(Increases heart rate, respiratory rate, etc) diverts blood flow to skeletal muscle, uses NE as a neurotransmitter in postganglionic neurons.

Parasympathetic = rest and digest; slows down body processes.

Diverts blodo flow to digestive and visceral organs and uses only ACh as a neurotransmitter.

The adrenal medulla is part of the sympathetic division, it produces epinephrine, which can bind to NE receptors to prolong and increase sympathetic effects

Question 29

Name the five classes of sensory receptors, what they respond to, and some examples of each

Answer 29

Mechanoreceptors respond to shape changes (Hearing receptors, touch receptors)

Thermoreceptors = temperature, hot/cold receptors

Nociceptors = pain receptors, are all over the body

Chemoreceptors = chemical changes, smell taste, and CO₂ receptors

Photoreceptors = light, rods and cones

Question 30

Describe the anatomy of the eye

Answer 30

• Iris is the colored part of the eye and regulates pupil diameter
• Lens is a biconvex structure that focuses light on the retina
• Cornea is the external transparent layer of the eye
• Pupil is the black opening in the middle of the eye
• Ciliary muscles regulate the curvature of the lens
• Fovea is responsible for visual acuity
• Retina is the layer at the back of the eye that is sensitive to light
• Optic disc = blind spot - place on the retina where the optic nerve forms (no photoreceptors)
• Optic nerve - a bundle of axons leaving the eye toward the brain

Question 31

Describe the anatomy of the ear

Answer 31

The outer ear (pinna) captures sound waves

Waves travel down the auditory canal where they vibrate the tympanic membrane

Vibrations are transmitted through the auditory ossicles (malleus, incus, and stapes) to the cochlea, which houses the basilar membrane and the hearing receptors.

Semicircular canals monitory dynamic equilibrium

Question 32

What is the difference between an endocrine and exocrine gland?

Answer 32

Endocrine secretes hormones directly into the blood

Exocrine secrete various products through ducts onto a body surface or cavity

Question 33

What are the differences between peptide and steroid hormones? Give some examples of each

Answer 33

Peptide hormones are amino acid based, bind to extracellular receptors, are fast-acting and temporary (Adrenaline, insulin, oxytocin)

Steroid hormones are cholesterol based, bind to intracellular receptors, are slow acting and more permanent. (Estrogen, testosterone, aldosterone, cortisol)

Question 34

For each of the following hormones, state where they come from, what causes their release, what their target organs are, and their function

Growth hormone, prolactin, TSH, ACTH, FSH, LH, oxytocin, ADH, thyroid hormone, aldosterone, cortisol, estrogen, progesterone, testosterone, insulin, and glucagon

Answer 34

Growth hormone - secreted from the anterior pituitary, is released due to exercise or other hormones, targets all cells, functions in growth and cell turnover

Prolactin - Anterior pituitary, nursing causes release, targets the mammary glands, and produces breat milk

TSH - anterior pituitary, stimulated by low thyroid hormone, targets the thyroid, increases thyroid hormone

ACTH - anterior pituitary, stimulated by low amounts of corticosteroids, targets the adrenal cortex, causes release of corticosteroids

FSH - anterior pituitary, low sex steroids triggers release, targets the ovaries/testes, causes egg/sperm maturation

LH - anterior pituitary, low sex steroids, targets ovaries/testes, stimulates ovulation and the release of progesterone/testosterone

Oxytocin = posterior pituitary, nursing/labor, targets reproductive smooth muscle, labor/milk ejection

ADH = posterior pituitary, stimulated by high blood osmolarity, targets kidney tubules to retain water

Thyroid hormone - thyroid gland, stimulated by low metabolism, targets all cells to increase metabolism

Aldosterone - adrenal cortex, released due to low blood pressure, targets the kidney tubules, to increase sodium retention

Cortisol - adrenal cortex, stimulated by stress, targets the liver, increase blood glucose

Estrogen - released from developing follice, triggered by FSH, targets the uterus and other body cells, functions in lining and female sex characteristics

Progesterone - corpus luteum, stimulated by LH, targets the uterus, maintains lining.

Testosterone - interstitial (Leydig) cells (testes), stimulated by LH, targets sperm/other body cells, functions in sperm production and male sex characteristics

Insulin - secreted from the pancreas due to increased blood glucose, targets all cells to reduce blood glucose

Glucagon - secreted from the pancreas due to low blood glucose, targets the liver to increase blood glucose.

Question 35

State the differences between arteries, veins, and lymphatic vessels in terms of structure, pressure, and fluid movement.

Answer 35

Arteries have a thick muscle layer to regulate flow, high blood pressure, pressure moves blood away from the heart, and is elastic

Veins/lymphatic vessels have a thin muscle layer, lower in pressure, move fluid through body movements, have valves, return fluid to the heart, are not elastic

Question 36

Trace the path of blood from the body, to the heart, to the lungs, back to the heart, and out to the body

Answer 36

Body, superior/inferior vena cava, R atrium. Tricuspid valve, R ventricle. Pulmonary semilunar valve, pulmonary artery, lungs. Pulmonary veins, L atrium, mitral/bicuspid valve, L ventricle, aortic semilunar valve, aorta, body

Question 37

Which two things is blood pressure directly proportional to?

Answer 37

Cardiac output (SV x HR) x Peripheral resistance

Question 38

How do a cardiac action potential and a neural action potential differ?

Answer 38

Neural AP is much quicker (2-3 msec); sharp upward spike due to Na/K channels

Cardiac AP is much longer (300 msec); plateau, Na+ K+, Ca2+ channels

Question 39

Trace the pathway of the cardiac conduction system

Answer 39

SA node, AV node, Bundle of His, Left and Right bundle branches, Purkinje fibers

Question 40

Name the primary functions of plasma, erythrocytes, leukocytes, and platelets

Answer 40

Plasma = transport cells, proteins, etc

Erythrocytes carry oxygen

Leukocytes are our disease defense

Platelets function in blood clotting

Question 41

How are oxygen and carbon dioxide carried through the blood stream?

Answer 41

Oxygen: 3% dissolved in plasma, 97% carried on hemoglobin in RBCs

Carbon dioxide: 7% dissolved in plasma, 20% carried on hemoglobin, 73% carried as bicarbonate ions in the plasma

Question 42

What is the basic structure of an antibody? What is its function? Which cells produce antibodies?

Answer 42

Antibodies bind specifically to a particular antigen and mark it for destruction or removal.

B cells produce antibodies

Question 43

What is autoimmunity?

Answer 43

Autoimmunity is an inappropriate immune reaction targeted at normal body structures

Question 44

Name three processes used by the kidney to form urine, and the region of the nephron in which these processes occur.

Answer 44

Filtration = glomerulus

Reabsorption and recretion = all other parts of the nephron tubule

Question 45

How and where do ADH and aldosterone affect the kidney?

Answer 45

ADH makes the collecting duct more permeable to water, causing increased water reabsorption

Aldosterone allows the distal convoluted tubule to reabsorb sodium

Question 46

When renin is released, how does it affect the body?

Answer 46

Renin is released when blood pressure is low, causing the conversion of angiotensinogen to angiotensin I

Angiotensin I is further converted to angiotensin II by ACE in the lungs.

Angiotensin II is a powerful vasoconstrictor, which raises blood pressure.

Angiotensin II also causes the release of aldosterone to retain sodium

Retention of sodium causes release of ADH and retention of water, causing increased blood volume and increased blood pressure.

Question 47

Name the organs of the alimentary canal, their functions, and the layers of the canal from the lumen outward

Answer 47

Mouth = chew, moisten food, and starch digestion

Esophagus moves food to the stomach

Stomach is our food storage, acid hydrolysis, and protein digestion

Small intestines are the main site of digestion and absorption

Large intestine = water reabsorption and fecal storage

Layers of canal from lumen outward = mucosa, submucosa, circular muscularis, longitudinal muscularis, serosa

Question 48

What are the digestive functions of the liver, pancreas, gallbladder, and salivary glands?

Answer 48

Liver produces bile (emulsifies fat for easier digestion)

Pancreas produces digestive enzymes and bicarbonate to raise intestinal pH

Gallblader stores and concentrates bile (Without, makes it more difficult to digest fats)

Salivary glands produce lysozymes to kill bacteria, amylase to digest starch, and water/mucus to bind/moisten food

Question 49

Describe the steps of the sliding filament theory of muscle contraction

Answer 49

Calcium is required

Myosin binds to actin, pulls actin toward the center of the sarcomere, releases actin (requiring ATP), resets and repeats

Question 50

Name the three muscle fiber types

Answer 50

Red slow twitch, Type IIA fibers, and type IIB fibers (white fast twitch)

Question 51

What are the differences between skeletal muscle, cardiac muscle, and smooth muscle

Answer 51

Skeletal muscle is multinucleate, voluntary, striated, and attached to bones

Cardiac muscle is uninucleate, involuntary, striated, and only in the heart

Smooth muscle is uninucleate, involuntary, nonstriated, and in hollow organs

Question 52

What are the functions of the skeletal system?

Answer 52

Support, protection, movement, mineral storage, and blood formation

Question 53

What is the difference between the conduction zone and respiratory zone?

Answer 53

Conduction zone - air tubes only, no gas exchange

Respiratory zone = gas exchange between lungs and blood

Question 54

How is respiratory (ventilation) rate regulated?

Name the receptors involved

Answer 54

Regulated primarily by the amount of CO2 (as acid) in the blood.

The peripheral (aortic/carotid bodies) and central chemoreceptors

Question 55

What are the differences between spermatogenesis and oogenesis?

Answer 55

Spermatogenesis occurs from puberty to death of males, million of sperm are produced daily, and for mature gametes (sperm) from a single precursor cell

Oogenesis = beings prenatally, meiosis is paused at prophase I, only finished if the oocyte if fertilized, and one oocyte is produced monthly

Question 56

Name and briefly describe the three phases of the uterine cycle and ovarian cycle. Which hormones control which phase?

Answer 56

Uterine cycle:

Menstruation, shed the old endometrium, very low estrogen and progesterone levels.

Proliferative phase: rebuild the endometrium, rising estrogen levels

Secretory phase: maintain and enhance the endometrium, stable levels of estrogen and progesterone

Ovarian cycle:

Follicular phase: build the follicle, controlled by FSH

Ovulation: release the oocyte, controlled by LH

Luteal phase, forms corpus luteum, controlled by LH

Question 57

How long is the embryonic period? The fetal period?

Answer 57

The embryonic period is the first eight weeks after fertilization

The fetal period lasts from the end of the embryonic until birth

Question 58

What is the difference between determination and differentiation?

Answer 58

Determined is when a cell is committed to a particular developmental fate, but may not ahve yet started the path to changing

Differentiation is the process by which a determined cell becomes its final mature version

Question 59

Which structures are part of the endoderm, mesoderm, and ectoderm

Answer 59

Endoderm - inner linings of respiratory, digestive, and urinary tract. Composes all glands

Mesoderm = bond, muscle, blood vessels, and non-gland organs (the heart)

Ectoderm = skin, hair, nails, nervous system

Question 60

What specifically do enzymes do to alter reaction rates?

Answer 60

Enzymes reduce activation energy to speed up reaction rates

Question 61

What is found at the active site of enzymes?

Answer 61

Anything that would stabilize the transition state: ions, charges amino acids, etc

Question 62

How do competitive, noncompetitive, and uncompetitive inhibitors differ by where they bind, and how do they affect V_max and K_m

Answer 62

Competitive: binds to active site, does not change V_max, increases K_m

Noncompetitive: binds to allosteric site, decreases V_max, no change to K_m

Uncompetitive inhibitors: bind to enzyme-substrate complex, decreases V_max and decreases K_m

Question 63

For glycolysis: what happens to the carbon chain? Where does ATP enter and exit? What are the end products? How are they prepared for the Krebs cycle

Answer 63

Six carbons (glucose) is phosphorylated twice, spltiting to 3 carbons and desphosphorylated to form pyruvate

ATP enters twice to phosphorylate glucose

ATP exits when the phosphorlyated carbon chain is split

End products are 2 net ATP, 2 NADH, and 2 pyruvate. Pyruvate must be decarboxylated to enter the Krebs cycle

Question 64

For Krebs: What happens to the carbon chain? Where do you make NADH, FADH₂, and GTP? How many NADH, FADH₂ and GTP are made per molecule of glucose?

Answer 64

Two carbons (acetyl-CoA) are added to 4 carbons (OAA) to make 6 carbons (citric acid). Is decarboxylated twice and isomerized back to OAA. 2 NADH during decarboxylation, 1 NADH, FADH, and 1 GTP during isomerization

6 NADH, 2 FADH₂ and 2 GTP per glucose

Question 65

For electron transport: Where are NADH/FADH₂ oxidized? How many ATP are made for each molecule? How are the ATP produced?

Answer 65

NADH is oxidized at the first proton pump in the inner mitochondrial membrane.

FADH₂ skips the first proton pump and is oxidized at coenzyme Q

2.5 ATP per NADH, 1.5 ATP per FADH₂

ATP is produced when protons move down the concentration gradient back into the matrix across an ATP synthase

Question 66

How many total ATP are made per glucose for aerobic respiration? How many for fermentation?

Answer 66

30 ATP for eukaryotes, 32 for prokaryotes. Total ATP for fermentation = 2

Question 67

What are the end products of fermentation for yeast? For muscle cells?

Answer 67

Yeast = 2 ethanol, 2 ATP

Muscle cells = 2 lactic acid, 2 ATP

Question 68

What are the main steps in regulation for gluconeogenesis, glycogenesis, glycogenolysis, and the pentose phosphate pathway?

Answer 68

Gluconeogenesis: PFK and F-1,6-BPase; an abundance of ATP or lack of glucose stimulated gluconeogenesis

Glycogenesis: stimulated by insulin, stimulates glycogen synthase

Glycogenolysis: Stimulated by glucagon (caused by low blood glucose), which stimulates glycogen phosphorylase

Pentose Phosphate Pathway: regulated primarily by NADPH; high levels turn off the pathway, low levels stimulate it.

Question 69

How do purines and pyrimidines differ in structure? How do they specifically bond DNA

Answer 69

Purines are a double ring

Pyrmidines are a single ring

Cytosine binds guanine (3H bonds)

Thymind binds adenine (2H bonds)

Question 70

Name and define the three types of point mutations. How serious are they? How serious are frameshift mutations? What is a translocation? What do transposons do?

Answer 70

Missense = new amino acid

Nonsense = stop codon

Silent = no change

Missense and nonsense severity depends on where in the protein the amino acid is affected and how drastic the change is

Silent mutations do not affect protein shape or function

Frameshift mutations are usually serious because every amino acid from that point forward is altered

Translocation moves large pieces of DNA from one chromosome to another

Transposon is a jumping gene that can excise itself (or copy itself) from one chromosome and insert itself in another. Depending on where it inserts it can cause genetic dysregulation

Question 71

Name and describe the different types of DNA repair

Answer 71

Direct reversal - enzyme directly fixes a mutation

Homology dependent repair - undamaged strand is used as a template to repair a damaged strand

DS break repair - can repair homologously or join broken ends, regardless if they are the correct ends or not

Question 72

What are some similarties and differences between replication and transcription? Briefly describe how they take place

Answer 72

Similarities - Both occur in the 5’ to 3’ direction and have definite start sites

Differences - replication is proofread and transcription is not; there is no stop site in replication, and transcription has a definite stop site. There is no primer needed for transcription

Replication begins at an origin, primase puts down an RNA primer. DNA polymerase replicates in both directions away from the origin. One strand leads one legs. The entire molecule is replicated

In transcription, RNA polymerase binds to a promoter, transcription begins at a start site and continues to the stop site. Only one strand of DNA is transcribed.

Question 73

Describe translation. Name the start and three stop codons

Answer 73

mRNA binds to the small ribosomal subunit, the first loaded tRNA binds at the P-site, and then all bind to the large subunit. The next loaded tRNA binds at the A-site, and then a peptide bond forms between first and second amino acids.

This breaks the bond between the first tRNA and the first AA. The entire complex shifts so that the second codon is now on the P-site. This repeats until the entire proton is translated.

Start codon = AUG = methionine

Stop codon = UAA, UGA< and UAG

4 x # AAs = amount of ATP needed

Question 74

Describe the lytic, lysogenic, and productive cycles

Answer 74

All cycles begin the same way with attachment and injection.

Lytic cycle = viral genome is immediately translated, new viral particles are made, the host cell is lysed to release new viruses

Lysogenic cycle = v iral genome is inserted into the host genome and replicated every time the host cell reproduces. At some point the viral genome is excised and enters the lytic cycle.

Productive cycle = Viral genome is immediately translated, new viral particles are made, and the virus buds out from the host cell and becomes covered in plasma membrane.

Question 75

What problems do +RNA and -RNA viruses have when trying to replicate? What special enzymes do they need?

Answer 75

To replicate +/- RNA viruses must be able to make a strand of RNA from a strand of RNA, which the host cell cannot do. Thus, the viruses need to make a special enzyme (RNA dependent RNA polymerase)

+RNA viruses only need to code for the enzyme since they are essentially mRNA and can be immediately translated

-RNA viruses just carry the enzyme with them since they are the template for mRNA and cannot be immediately translated; the + strand must be made first

Question 76

Classify bacteria by cell wall/membranes, preferred temperature, and energy/nutrient requirements

Answer 76

Gram+ = thick cell wall, inner membrane (purple)

Gram(-) = thin cell wall, inner/outer membranes (more resistant to antibiotics due to periplasmic space)

Thermophiles = hot temps

Mesophiles = medium temps

Psychrophiles = cold temps

Photoautotrophs use light energy and CO2 to make their own carbon chains

Chemoheterotrophs rely on chemical energy (ATP) and consume other organisms to get their carbon chains (humans)

Chemoautotrophs rely on ATP and make their own food (deep sea vent bacteria)

Photoheterotrophs use light energy and eat other organisms (venus fly trap)

Supercript^- = bacteria can’t do something; can’t make arginine, can’t metabolize lactose

Question 77

What is the difference between bacterial asexual reproduction and conjugation?

Answer 77

Bacterial asexual reproduction = binary fission, increases population size without mixing up the genetic information

Conjugdation = only purpose is to exchange DNA, does not result in a bigger population

Question 78

Name the three fibers in the cytoskeleton and their functions.

What are tight junctions? Gap junctions?

Answer 78

Microtubules = spindle, flagella, cilia, organelle movement

Microfilaments = contraction

Intermediate filaments = structure and shape

Tight junctions seal space between two cells so that molecules cannot pass between the cells (Intestines, blood brain barrier)

Gap junctions are like protein tunnels connecting two cells that allow cytoplasm and other substances to flow freely (cell-to-cell communication) (the heart)

Question 79

Describe the structure of the plasma membrane

Answer 79

A mosaic of phospholipids (lipid bilayer), cholesterol, proteins (which may pass all the way through or associate with one side) and carbohydrates (Only on extracellular side, attached to proteins or lipids)

Question 80

Define simple diffusion, facilitated diffusion, exocytosis, endocytosis, primary active transport, and secondary active transport

Answer 80

Simple diffusion = molecule crosses membrane according to concentration gradient

Facilitated diffusion = molecule crosses the membrane through a special protein according to concentration gradient

Exocytosis = cell secretes a product from a vesicle

Endocytosis = cell takes up a substance in a vesicle

Primary active transport = cell uses ATP directly to pump molecules against a concentration gradient (Na/K ATPase)

Secondary active transport = relies on Na+ gradient set up by primary active transport to drive co-transport of other molecules across the membrane

Question 81

Describe a basic second messenger system (G proteins)

Answer 81

A molecule binds to an extracellular receptor, which causes an associated G protein on the intracellular side to bind to GTP.

The G protein with GTP bound now activated adenylate cyclase, which causes the production of cAMP

cAMP activates cAMP-dependent protein kinases, phosphorylate enzymes, turning them on or off.

This is also an example of signal amplification, since at every step the number of activated molecules increases and the binding of a single ligand to a receptor results in multiple enzymes being affected.

Question 82

What are the subphases of interphase?

In which phase do nondividing cells remain?

Answer 82

Subphases are G₁ S and G₂

Nondividing cells (muscle, nerves, etc) stay in G₁

Question 83

Briefly describe the process of apoptosis

Answer 83

Apoptosis is triggered when a stressor (toxin, DNA damage) reaches a critical level

Proteins called caspases are involved.

Initiator caspases activate effector caspases, which are digestive enzymes.

Effector caspases cleave cellular proteins and trigger the shrinking of the cell membrane by breaking down the nucleus and cytoskeleton and signal phagocytotic cells that the dead cell is ready to be cleared away

Question 84

What does 2n and 1n mean?

How many chromosomes are in human cells?

Answer 84

2n = diploid (2 homologous copies of each type of chromosome)

1n = haploid (1 copy of each chromosome)

n = # of different types of chromosomes

Humans have 2(23) = 46 total chromosomes

Question 85

In meiosis, when do homolgous chromosomes separate?

Answer 85

At anaphase I

Question 86

Define classical dominance, incomplete dominance, codominance, and epistasis

Answer 86

Classical dominance = One allele is expressed, one is silent.

Incomplete dominance = neither allele is silent, both are expressed as a blended phenotype (flower color)

Codominance = neither allele is silent, both expressed equally and distinctly (blood type AB)

Epistasis = suppression of the effect of a gene by a nonallelic gene (Baldness and hair color)

Question 87

What is a testcross?

Answer 87

A cross between a homozygous recessive and an unknown genotype

Question 88

Why do sex-linked diseases and conditions affect males more frequently than they effect females?

Answer 88

If a disease is on the Y chromosome, only males have a Y

If a disease is on the X chromosome, males only have one X, so whatever they have is expressed. (Females have two, so one good X and compensate for a bad X)

Question 89

State Mendel’s Law of segregation and the Law of Independent Assortment

Answer 89

Law of segregation = alleles are separated during meiosis

Law of independent assortment = how alleles for one gene are separated has no bearing on how alleles for other genes are separated

Question 90

When can you suspect that two genes are linked?

What is the recombination frequency of linked genes?

Answer 90

After a cross between two difference genes, the expected Mendelian ratios are not what would be expected between unlinked genes. In other words, the alleles do not sort independently.

Or when the RF < 50%

RF = (# recombinants)/(total offspring)

Question 91

What is rest potential and how is it maintained?

Answer 91

Rest potential is the potential difference of -70 mV across the cell membrane

It is maintained by the Na/K+ ATPase and the K+ leak channels

Question 92

What is the difference between absolute and relative refractory periods?

Answer 92

Absolute = absolutely impossible to fire a second action potential; Na channels are inactivated, the cell is in positive potentials.

Relative = possible, but difficult to fire a second AP; Sodium channels are now closed; the cell is hyperpolarized and farther from threshold.

Question 93

Describe transmission at a chemical synapse. How can the postsynaptic neuron be excited or inhibited?

Answer 93

An AP in the presynaptic axon opens VG-Calcium channels, allowing the influx of calcium

Increased [Calcium] breaks the bonds holding the neurotransmitter vesicles to the cytoskeleton. Vesicles migrate to the membrane and exocytose, releasing neurotransmitters into the synaptic cleft, where it binds to receptors on the postsynaptic cell.

Binding of neurotransmitter to receptor causes EPSPs or IPSPs on the postsynaptic cell.

Postsynaptic cell is excited or inhibited depending on the sum of all EPSPs and IPSPs

Question 94

What is the difference between an afferent and efferent neuron?

Answer 94

Afferent neurons send impulses toward the CNS (Sensory)

Efferent neurons send impulses away from the CNS (Motor)

Question 95

What are the major functions of the medulla, pons, midbrain, cerebellum, epithalimus, thalamus, hypothalamus, lobes of the cerebral cortex, and the corpus callosum?

Answer 95

Medulla - basical vital functions, special respiratory/digestive functions

Pons = facial movement and balance

Midbrain = visual/auditory startle reflexes

Cerebellum = smooth body movement, coordination

Epithalimus = sleep/wake cycles

Thalamus = sensory relay station (Besides olfactory)

Hypothalamus = Homeostasis

Frontal lobe = voluntary movement, reasoning

Parietal lobe = general sensation and taste

Temporal lobe = auditory sensation, memory, and smell

Occipital lobe = vision

Corpus callosum = relays information between cerebral hemispheres

Question 96

What are the functions of the auditory tube, cochlea, and semicircular canals?

Describe auditory processing. How does the basilar membrane work?

Answer 96

Auditory tube = equalizes pressure on either side of the tympanic mebrane

Cochlea = hearing

Semicircular canals = equilbrium

Sound waves set up vibration in the cochlear fluid, which sets up waves along the basilar membrane. Hair cells on the basilar membrane move when the membrane moves, and the bending of the hair cells sends an action potential along the auditory nerve.

Pitch is determined by the region of the basilar membrane most stimulated. The basilar membrane is thick and stiff at the round window and floppy at the end.

High frequency tones tend to vibrate the thicker area more, and low frequency tones vibrate the apex more

Question 97

Describe visual processing

Answer 97

Light striking a photoreceptor causes a sodium channel to close; the normal open state of this channel means the cell is depolarized at rest. Closure of the channel causes the cells to hyperpolarize and stop releasing an inhibitory neurotransmitter onto the bipolar cells. This causes bipolar cells to fire an action potential, stimulating ganglion cells and sends an action potential into the brain along the optic nerve

Question 98

What type of tissue is the anterior pituitary gland made of? The posterior pituitary gland?

Compare control of the anterior and posterior pituitary glands

Answer 98

Anterior pituitary = gland tissue (adenohypophysis)

Posterior pituitary - nervous tissue (neurohypophysis)

Anterior is controlled by hormones released from the hypothalamus

Posterior is controlled by action potentials from the hypothalamus

Question 99

What is the difference between diastole and systole?

What causes heart sounds?

Answer 99

Diastole is when the ventricles are relaxed

Systole is when the ventricles are contracted.

The first heart sound in the closing of AV valves and the beginning of systole

The second heart sound is the closing of semilunar valves and the beginning of diastole

Question 100

How can cardiac output be calculated? What is Starling’s Law of the Heart?

How can peripheral resistance be changed?

Answer 100

CO = Stroke volume x heart right

Starling’s Law: More blood in, more blood out (Increased venous return increases cardiac contractility and stroke volume)

Peripheral resistance is changed by changing arterial diameter; vasodilation leads to a drop in resistance

Question 101

How do cardiac action potentials differ from neural action potentials?

What other ion channel is involved?

Answer 101

Cardiac action potentials are longer, as they have a plateau phase due to VG-Calcium channels

Question 102

Give three reasons for the elaborate cardiac conduction pathway

Answer 102

1. It is impossible to directly transmit an impulse from atria to ventricles, so the only way the impulse can get into the ventricles is through the conduction system
2. The AV node delays the impulse slightly so that the atria can contract first, allowing the ventricles to fill completely.
3. The impulse travels to the bottom of the ventricles before entering ventricular muscle cells so that the ventricles contract from bottom to top (Better ejection efficiency)

Question 103

Name the nonspecific disease defense systems of the body.

What cells are involved in immunity and what are their functions?

Answer 103

Nonspecific defense:

Barriers: skin, hair, earwax, skin oil, mucus,

Chemicals: lysozymes, gastric stomach acid, pepsin, proteases, the complement system (enhances the ability of antibodies and phagocytic cells)

Cells: macrophages, neutrophils, eosinophils, dendritic cells, NK cells

Immunity is a specific defense;

• B cells:* humoral immunity; make antibodies, can only produce one type of antibody, but can alter their genes to produce different types; have an antigen receptor on their cell surface
• T Cells* - cell-mediated immunity, look to kill antigens directly; have a self receptor and antigen receptor, both must be stimulated for the cell to be active
• Killer T cells* (CD8) bind and kill abnormal self-cells; associated w/ MHC1 - found on all cells; allowing cells to display their contents on the cell surface
• Helper T* (CD4) - secrete cytokines that help B cells and killer T cells proliferate; associated with MHC2 - MHC2 is found on macrophages and B Cells; allows cells to display what is eaten on the cell surface

Question 104

Besides urine production, what are the other functions of the kidney?

Answer 104

Regulated blood presure, pH, ion/water balance, activated viatmin D, and secretes eryhtropoietin (EPO) to increase red blood cell formation

Question 105

What is unique about the bklood supply to and from the glomerulus?

Answer 105

It is both supplied and drained by arteries, allowing regulation of blood flow in and out

Question 106

List the skeletal muscle hierarchy

Answer 106

Myosin, actin, sarcomere, myofibrils, muscle cell, fascicle, muscle

Question 107

What is excitation-contraction coupling?

What types of motor units do the fingers have? The legs?

Answer 107

The coupling of contraction (sliding filaments) with excitation (a neural AP) through use of Calcium.

Fingers have many small motor units, legs have a few large motor units

Question 108

What are the sources of muscle energy, from fastest source to slowest source? What is the oxygen debt and how is it repaid?

Answer 108

Muscle gets energy (ATP) by substrate-level phosphorylation (taking phosphate off creatine phosphate and putting it on an ADP to generate an instant ATP), by glycolysis, and by aerobic cellular respiration.

Oxygen debt is the additional oxygen required after exercise to replenish oxygen stores on myoglobin and to convert lactic acid into something useful.

The debt is repaid through the Bohr effect (Increased CO₂, increased temperature, and decreased pH), which causes hemoglobin to have a lower affinity for oxygen and release more oxygen to the tissues

Question 109

Describe the three skeletal muscle fiber types in terms of their energy usage and contraction speeds

Answer 109

Red slow twitch fibers contract slowly, use oxidative metabolism, and are fatigue resistant (Posture muscles)

Type IIB (White fast twitch) contract rapidly, are glycolytic only, and fatigue quickly.

Type IIA fibers contract quickly, are oxidative, and are more fatigue resistant than type IIB, but not as much as red slow twitch.

Question 110

Define osteoblast, osteocyte, and osteo clast.

What hormones affect these cells and how?

Answer 110

Osteoblast = immature bone-producing cell

Osteocyte = masture bone cell in lacuna

Osteoclast = bone-dissolving cell

PTH increases blood calcium levels by stimulating osteoclasts and inhibiting osteoblasts

Calcitonin decreases b lood calcium levels by stimulating osteoblasts and inhibiting osteoclasts

Question 111

Name the structures of the conduction zone and respiratory zone

Answer 111

Conduction zone: nose, nasal cavity, pharynx, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, terminal bronchioles

Respiratory zone = respiratory bronchioles, alveolar ducts, alveoli

Question 112

How does surfactant make breathing easier?

Answer 112

It reduces the surface tension on the inside wall of the alveoli, preventing them from collapsing and reducing the effort required to inflate them

Question 113

Which muscles control inspiration? Expiration? Forced Expiration?

Answer 113

Inspiration = diaphragm/external intercostals

Expiration = none

Forced expiration = abdominals/ internal intercostals

Question 114

Define tidal volume, residual volume, vital capacity, and total lung capacity

Answer 114

Tidal volume = normal resting breath volume (500 mL)

Residual volume = amount remaining in the lungs after complete exhale (1200 mL)

Vital capacity = maximal inhale after a maximal exhale, (4500 mL)

Total lung capacity = total lung volume (5700 mL)

Question 115

Name the layers of the skin and their tissues

How does the skin help regulate body temperature?

Answer 115

Epidermis = epithelial tissue

Dermis = connective tissue

Hypodermis = fat

The skin helps in thermoregulation by sweating and vasodilation in hot temperatures/ not sweating and vasoconstriction in cold temperatures

Question 116

Name the structures and functions of the male reproductive system

Answer 116

Scrotum = regulates temperature of thetestes

Testes = produce sperm and testosterone

Epididymis = sperm storage

Vas deferns = contracts for ejaculation

Seminal vesicle = produces 60% of semen

Prostate = produces 35% of semen

Bulbourethral glands - produce alkaline mucus to lubricate, neutralize the urethra

Penis = becomes ereject to inject sperm/semen

Question 117

Name the structures and functions of the female reproductive system

Answer 117

Labia = protects the vulva

Clitoris = erectile tissue

Vestibular glands = lubrication

Vagina = birth canal

Cervix = opening to the uterus

Ovaries = egg, estrogen, and progesterone production

Mammary glands produce breast milk

Question 118

What causes differentiation of a fetus into a male?

Answer 118

The presence of a Y chromosome triggers the production of the testes.

The testes secrete testosterone, which allows the Wolffian (male) ducts to develop, as well as Mullerian Inhibiting Factor (MIF) which causes the Mullerian ducts to degenerate

Question 119

Which division of the autonomic NS controls arousal, orgasm, and resolution respectively

Answer 119

Arousal = parasympathetic

Orgasm and resolution = sympathetic

Question 120

Describe the proces of fertilization, cleavage, blastulation, gastrulation, and neurulation

Answer 120

Fertilization: Sperm penetrates the egg, the egg finishes meiosis, the nuclei fuse

This can occur about 14-16 days after menstruation

Cleavage is the rapid cell division of the zygote, occuring the first week after fertilization

Blastulation is the formation of a hollow sphere with inner cell mass and an outer cell layer, occurs during the last few days of cleavage before implantation

Gastrulation is the formation of the three distinct germ layers, occurs in weeks 1-3 after implantation

Neurulation = formation of the nervous system, occurs weeks 4-8 after implantation

Question 121

What is the difference between totipotency, pluripotency, and multipotency?

Answer 121

Totipotent cells can become any cell type in the embryo or placenta
The zygote is totipotent

Pluripotent cells can differentiate into any of the cells in the three primary germ layers, and can become any of the 200+ cell types in the human body; The cells of the inner cell mass (Embryonic stem cells) are pluripotent

Multipotent cells are more specialized and can become many, but not all cell types. The cells of different germ layers are multipotent; ie the cells of the mesoderm can become bone or muscle cells, but not neurons or liver cells

Question 122

What hormonal changes occur in a woman during pregnancy?

Which hormone is used to test for pregnancy?

Answer 122

Developing embryo cells secrete hCG, which prolongs the life of the corpus luteum so that it continues to secrete progesterone and estrogens. hCG levels stay high for the first trimester until the placenta is formed.

The placenta secretes large amounts of estrogen to develop the mammary glands, progesterone to maintain the uterine lining, and relaxin to soften joints.

The high levels of estrogen and progesterone inhibit the release of FSH and LH

Question 123

What factors trigger labor?

Describe the positive feedback system in operation during labor

Answer 123

1. Growing fetus stretches the uterus
2. Stretch of the cervix increases uterine contractions
3. Increased oxytocin secretion
4. Increased estrogen relative to progesterone

Baby’s head presses on the cervix, stimulating uterine contractions and oxytocin release.

Contraction of the uterus pushes the baby’s head against the cervix, stimulating further contractions

Question 124

What changes occur in the fetal circulation after birth?

What changes occur in the month after birth?

Answer 124

1. Ductus arteriosis closes, redirecting blood through the lungs
2. Foramen ovale closes, separating the right and left atria
3. Ductus venosus closes, redirecting blood through the liver
4. Umbilical arteries and veins constrict
5. Baby stops making fetal hemoglobin

In the mother: delivery of the placenta causes estrogen and progesterone levels to drop dramatically. Drop in these hormones releases inhibition of prolactin, causing the release of prolactin, causing breast milk production.

Question 125

What is nondisjunction?

When can this occur and what is the result?

Answer 125

Nondisjunction is the failure to properly separate DNA during gamete formation.

Anaphase I failure - 4 abnormal gametes

Anaphase II failure - produces 2 abnormal gametes

Question 126

Describe the secretory pathway

Answer 126

ER –> Golgi –> Secretory vesicles –> exterior via exocytosis or storage or lysosomes

Question 127

Ribosomes of the rough ER secrete what kinds of proteins?

Answer 127

Membrane-bound, secreted, and integral proteins

Question 128

What are the components of the cytoskeleton and what are their features/functions?

Answer 128

Microtubules are composed of alpha and beta tubulin

Have a large diameter and form the mitotic spindle, participate in intracellular transport and make up cilia and flagella

Microfilaments are composed of actin and have a small diameter

Function in muscle contraction, pseudopod formation (macrophages), and cytokinesis

Intermediate filaments are composed of many types of proteins, serve structural roles, and are more permanent than other parts of the cytoskeleton.

Question 130

What are the characteristics of G protein receptors?

Answer 130

G proteins have inherent GTPase activity, where it constantly hydrolyzes GTP into GDP. As such, at rest GDP is bound to the alpha receptor subunit

G proteins are multisubunit proteins, allowing one subunit to migrate and activate Adenylyl Cyclase.

cAMP is a second messenger system, because the ligand can’t cross the cell membrane and has to drive the release of a second messenger.

Is a form of signal amplification (activation of multiple G-proteins by the bound receptor)

Are fast and temporary; fast because you simply activate the pathway, and temporary due to the inherent GTPase activity

Question 131

What three amino acids can be phosphorylated?

Answer 131

Serine, threonine, and tyrosine

Question 132

Which proteins finish translation in the Rough ER?

Describe their signal sequence

Answer 132

Secreted proteins, lysosomal proteins, and transmembrane proteins finish translation in the rough ER.

Signal sequence of secreted and lysosomal proteins:

is the first few amino acids translated and is removed upon completion of translation

Membrane-bound proteins:

Signal sequence can be anywhere in the amino acid sequence

Signal sequence can appear multiple times

Signal remains as part of the transmembrane part of the protein (Removal would cause the protein to fall apart.)

Question 133

Define zymogens

Answer 133

Zymogens are inactive precursors of enzymes that are usually activated by cleavage and are involved in the breakdown of proteins.