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Bio/Biochem Flashcards

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1
Q

Chirality of AAs

A

All AAs are chiral (L) except glycine and they all are S except cysteine.

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2
Q

Nonpolar, nonaromatic AAs

A

glycine, alanine, valine, leucine, isoleucine, methionine, proline

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3
Q

Aromatic AAs

A

Tyrosine, tryptophan, pheynylalanine

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4
Q

Polar AAs

A

Serine, threonine, glutamine, asparagine, cysteine

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5
Q

Negatively Charged AAs

A

Glutamate and aspartate

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6
Q

Positively Charged AAs

A

Lysine, arginine, histadine

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7
Q

pI determination of AAs

A

Average of pKa values for each H of the AA

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8
Q

Peptide bond formation/breakdown

A

Condensation (dehydration) reaction to form with nucleophilic amino group attacking electrophilic carbonyl; hydrolysis to break

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9
Q

Primary structure

A

The AA sequence

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10
Q

Secondary Structure

A

local structure stabilized by H-bonding; includes a helices and beta pleated sheets

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11
Q

Tertiary Structure

A

3D structure stabilized by hydrophobic interactions, acid base interactions (salt bridges), hydrogen bonding, and disulfide bonds

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12
Q

Quaternary structure

A

Interactions between subunits.

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13
Q

Denaturation

A

Caused by heating or solutes.

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14
Q

Structural Proteins

A

Fibrous; include collagen, elastin, keratin, tubulin, actin

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15
Q

Motor Proteins

A

Capable of force generation through conformational change; myosin, kynesin, dynein

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16
Q

Binding Proteins

A

Bind a specific substrate, either to sequester it in the body or hold its concentration at a steady state

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17
Q

Cell Adhesion Molecules (CAMs)

A

Bind cells to other cells or surfaces, include cadhedrins, integrins, and selectins

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18
Q

Antibodies (immunoglobulins Ig)

A

Target a specific antigen which may be a protein in the surface of a pathogen or a toxin

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19
Q

Ligases

A

Join two large biomolecules, often of the same type

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20
Q

Isomerases

A

Catalyze the interconversion of isomers, including both constitutional and stereoisomers

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21
Q

Lyases

A

Catalyze cleavage without the addition of water and without the transfer of electrons; the reverse reaction (synthesis) is usually more biologically important

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22
Q

Hydrolases

A

Catalyze cleavage with the addition of water

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23
Q

Oxidoreductases

A

Catalyze oxidation reduction reactions that involve electron transfer.

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24
Q

Transferases

A

Transfer function groups between molecules

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25
Q

Enzyme Mechanisms

A

Enzymes lower the activation energy of the reaction, thereby increasing the rate (kinetics) without altering the thermodynamics (∆G, ∆H) or the equiibrium

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26
Q

Competitive Inhibition

A

Binds to active site, raises Km, no change to Vmax

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27
Q

Noncompetitive Inhibition

A

Binds to allosteric site (present regardless of substrate); no change to Km, Vmax lowered

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28
Q

Mixed inhibtion

A

Binds to allosteric site, Km increases or decreases, Vmax lowered

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29
Q

Uncompetitive Inhibition

A

Binds to allosteric site (present only when substrate is bound); Km decreases, Vmax lowered

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30
Q

Michaelis-Menten Curve

A

Reaction velocity vs. Substrate concentration; Vmax is asymptote, Km is [S] when v = 1/2 Vmax

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31
Q

Lineweaver-Burk Plot

A

Y intercept is 1/vmax, X intercept i -1/Km; cooperative enzymes show a sigmoidal curve

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32
Q

3, 4, 5 carbons sugars

A

triose, tetrose, pentose

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33
Q

Aldose

A

Sugars with aldehydes as their most oxidized group

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34
Q

Ketose

A

Sugars with ketones as their most oxidized group

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35
Q

Chirality of Sugars

A

If the highest numbered chiral carbon with an OH group is on the right –> D; if left –> L

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36
Q

Enantiomers

A

Differ at all chiral centers

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37
Q

Diastereomers

A

Differ at at least one - but not all - chiral centers

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38
Q

Epimer

A

Differ at exactly one chiral center (type of diastereomer)

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39
Q

Anomer

A

A type of epimer that differs at the anomeric carbon

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40
Q

Anomeric carbon

A

When a sugar cyclizes, this carbon takes on either alpha or beta conformation and is a new chiral center; the carbon containing the carbonyl in the straight chain form

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41
Q

Alpha vs Beta sugars

A

alpha anomers: have the -OH on the anomeric carbon trans to the free -CH2OH group

beta anomers: have the -OH on the anomeric carbon cis to the free -CH2OH group

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42
Q

Mutarotation

A

Process by which one anomer shifts to another with the straight chain form as an intermediate

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43
Q

Reactions of monosaccharides

A

Redox; esterification; glycoside formation (basis for building complex carbohydrates and requires anomeric carbon to link to another sugar)

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44
Q

Deoxy sugars

A

Sugars with an -H replacing and -OH

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45
Q

Sucrose

A

glucose-alpha-1,2-fructose

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46
Q

Lactose

A

galactose-beta-1-4-glucose

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47
Q

Maltose

A

glucose-alpha-1,4-glucose

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48
Q

Cellulose

A

Main structural component of plant cell walls; main source of fiber in the human diet

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49
Q

Starches (amylose and amylopectin)

A

Main energy storage forms for plants

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50
Q

Glycogen

A

A major energy storage form for animals

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51
Q

Nucleoside

A

Five carbon sugar bound to a nitrogenous base

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52
Q

Nucleotide

A

A nucleoside with 1-3 phosphate groups added

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53
Q

Purines

A

Adenine and guanine; double-ringed

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54
Q

Pyrimadines

A

Cytosine, uracil, and thiamine; single-ringed

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55
Q

Differences between Euk/Prok replication

A

Euk: Nucleotides added by DNA polymerases alpha and delta, RNA primers removed by RNase H, primers replaced by DNA polymerase delta; has telomeres synth by telomerase

Prok: Nucleotides added by DNA polymerase III, RNA primers removed and replaced by DNA polymerase I

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56
Q

Nucleosome

A

When DNA is wound around histones

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57
Q

Heterochromatin

A

Dense, transcriptionally silent, DNA

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58
Q

Euchromatin

A

Less dense, transcriptionally active DNA

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59
Q

Genomic Library

A

Contains large fragments of DNA, including introns; cannot be used to make recombinant proteins or for gene therapy

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60
Q

cDNA library

A

Contains smaller fragments of DNA only including the exons of genes expressed by the sample tissue; can be used to make recombinant proteins or for gene therapy

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61
Q

Start codon

A

AUG

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62
Q

Stop codons

A

UAA, UGA, UAG

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63
Q

What helps prevent mutations from affecting codons?

A

Redundancy and wobble

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64
Q

Nonsense mutations

A

Premature stop codon

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65
Q

Missense mutations

A

Produces a codon that codes for a different AA

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66
Q

Frameshift mutations

A

Result from nucleotide addition or deletion and change the reading frame of the subsequent codons

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67
Q

RNA is structurally similar to DNA except:

A

Ribose instead of deoxyribose, uracil for thiamine, single stranded instead of double stranded

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68
Q

Steps in transcription

A

1) DNA helicase and topoisomerase unwind the double helix
2) RNA pol II binds to the TATA box in the promoter region of the gene (25 bp upstream of first transcribed base)
3) hnRNA is synthesized from antisense strand of DNA
4) 5’ cap and poly-A tail added
5) Spliceosome removes introns and ligates exons together

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69
Q

Transation Stages

A

1) initiation
2) elongation
3) termination
4) posttranslational modifications including: folding by chaperones, formation of quaternary structure, cleavage of proteins or signal sequences, and covalent addition of other biomolecules

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70
Q

Difference between promoters and enhancers (eukaryotes)

A

Promoters are within 25 bp of the first transcription site, enhancers are farther upstream than 25 bp

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71
Q

Osmotic Pressure

A

The pressure applied to a pure solvent to prevent osmosis; π = iMRT where i is the van’t hoff factor

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72
Q

Passive Transport

A

Movement of molecules down concentration gradient w/o ATP

1) simple diffusion - small nonpolar molecules do not req. transporters
2) osmosis - the movement of water across selectively permeable membrane
3) facilitated diffusion - uses transport proteins to move impermeable solutes across the cell membrane

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73
Q

Active Transport

A

Requires energy in the form of ATP (primary) or an existing favorable gradient (secondary) –> secondary can be symport or antiport

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74
Q

Endocytosis and Exocytosis

A

Both methods of engulfing material into cells or releasing material to the exterior of cells, both via the cell membrane

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75
Q

Pinocytosis and Phagocytosis

A

The ingestion of liquid and solid, respectively, into the cell from vesicles formed from the cell membrane

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76
Q

Glycolysis location and yield

A

Cytoplasm of all cells; 2 ATP per glucose

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77
Q

Glycolysis key enzymes - describe and star irreversible.

A

Gluco/hexokinase* - traps glucose

PFK-1* - rate limiting step

PFK-2 - produces F2,6BP which activates PFK-1

G3PDH - produces NADH

3-phosphoglycerate kinase and pyruvate kinase* - perform substrate level phosphorylation

78
Q

What is the fate of the NADH produced in glycolysis?

A

Oxidized aerobically by the ETC or anaerobically by cytoplasmic lactate dehydrogenase

79
Q

What is the function of pyruvate dehydrogenase? How is it regulated?

A

Converts pyruvate to acetyl-CoA for Krebs cycle, producing 2 NADH per glucose (one per pyruvate). Stimulated by insulin and inhibited by acetyl CoA.

80
Q

Where is the Citric Acid Cycle and what is its purpose?`

A

Mitochondrial matrix; to oxidize acetyl-CoA to CO2 and generate high-energy electron carriers (NADH and FADH2) and GTP

81
Q

What is the net yield of citric acid cycle per glucose?

A

6 NADH, 2 FADH2, 2 GTP

82
Q

Where is the ETC and how does it function?

A

Matrix-facing surface of the inner mitochondrial membrane; NADH donates electrons to the chain, which are passed from one complex to the next via increasing reduction potentials –> O2 is the final acceptor and has the highest reduction potential

83
Q

How does NADH transfer it’s electrons to the ETC inside of the inner mitochondrial membrane?

A

Glycerol-3-phosphate shuttle and malate-aspartate shuttle

84
Q

What is the proton-motive force?

A

The electrochemical gradient generated by the electron transport chain across the inner mitochondrial membrane; intermembrane space has more protons than the matrix

85
Q

What is chemiosmotic coupling?

A

How ATP synthase uses energy from the proton gradient to power the unfavorable synthesis of ATP from ADP and Pi.

86
Q

How many ATP per NADH and FADH2

A

NADH - 2.5

FADH2 - 1.5

87
Q

Net yield of aerobic metabolism per glucose?

A

2 (glycolysis) + 2 (citric acid cycle - from GTP) + 25 (NADH) + 3 (FADH2) = 32 if optimal conditions

88
Q

What is glycogenesis?

A

Glycogen synthesis

89
Q

What two enzymes complete glycogenesis?

A

Glycogen synthase - created alpha-1,4 glycosidic links between glucose molecules; activated by insulin in the liver and muscles

Branching enzyme - moves a block of oligoglucose from one chain and connects it as a branch using an alpha-1,6 glycosidic link

90
Q

What is glycogenolysis?

A

The breakdown of glycogen

91
Q

What two enzymes complete glycogenolysis?

A

Glycogen phosphorylase - removed single glucose 1-phosphate molecules by breaking alpha-1,4 glycosidic links; in liver, activated by glucagon to prevent low blood sugar, in skeletal muscles, activated by epinephrine and AMP to provide glucose for the muscle

Debranching enzyme - moves a block of oligoglucose from one branch and moves it to the chain with an alpha-1,4 glycosidic link

92
Q

What is gluconeogenesis? How are the irreversible reactions bypassed?

A

De novo synthesis of glucose in the liver (cytoplasm and mitochondria); uses same enzymes as glycolysis in reverse

1) pyruvate kinase bypassed by pyruvate carboxylase and PEP carboxykinase
2) F1,6Bphosphase bypasses PFK-1
3) gluco/hexokinase bypassed by G6phosphatase

93
Q

What is the Pentose Phosphate pathway and where does it occur?

A

Generates NADPH to rereduce antioxidants and ribose as a base for nucleotides; occurs in the cytoplasm

94
Q

What characterizes the postprandial (fed) state?

A

Insulin secretion is high and anabolic (synthesis) metabolism prevails

95
Q

What characterizes the postabsorptive (fasting) state?

A

insulin secretion decreases while glucagon and catecholamine secretion increase

96
Q

What characterizes the starvation state?

A

Dramatic increases of glucagon and catecholamines; tissues rely on fatty acids

97
Q

How are lipids transported in the blood?

A

Chylomicrons, VLDL, IDL, LDL, HDL

98
Q

How is cholesterol obtained?

A

Dietary sources or biosynthesis in the liver by HMG-CoA reductase

99
Q

What fatty acid can humans synthesize?

A

Palmitic Acid; produced in cytoplasm from acetyl CoA transported out of the mitochondria

100
Q

Where does FA metabolism occur and how is transport achieved?

A

FAs are oxidized in the mitochondria via beta-oxidation following transport by the carnitine shuttle

101
Q

Why do ketone bodies form during starvation?

A

Excess acetyl-CoA in the liver

102
Q

What is Ketolysis?

A

Regenerates acetyl-CoA for use in the liver

103
Q

Where are proteins digested and how are the raw materials used?

A

In the small intestine by pepsin; carbon skeletons of AAs are used for energy via gluconeogenesis or ketone body formation; amino groups are fed into the urea cycle for secretion

104
Q

What is the liver’s function in metabolism?

A

Maintains blood glucose through glycogenolysis and gluconeogenesis; processes lipids, cholesterol, bile, urea, and toxins

105
Q

What is the adipose tissue’s function in metabolism?

A

stores and releases lipids

106
Q

What is resting muscle’s use of metabolism?

A

Conserves carbohydrates as glycogen and uses free fatty acids as fuel

107
Q

What is active muscle’s use of metabolism?

A

May use anaerobic metabolism, ox phos, direct phos (creatine phosphate), or fatty acid oxidation

108
Q

What is cardiac muscles’s use of metabolism?

A

uses fatty acid oxidation

109
Q

What is the brain’s use of metabolism?

A

uses glucose except in prolonged starvation when it can use ketolysis

110
Q

Nucleus

A

contains genetic material necessary for cell replication

111
Q

Mitochondrion

A

site of many metabolic processes including pyruvate dehydrogenase, the citric acid cycle, electron transport chain, beta oxidation, gluconeogenesis, urea cycle, and ATP synthesis

112
Q

Lysosomes

A

Membrane-bound structures containing hydrolytic enzymes capable of breaking down many different substrates

113
Q

Rough ER

A

interconnected membranous structure that contains ribosomes responsible for translation of new proteins destined for insertion into membranes or secretions

114
Q

Smooth ER

A

interconnected membranous structure where lipid synthesis and detoxification occurs

115
Q

Golgi apparatus

A

Membrane-bound sacs where post-translational modification of proteins occurs

116
Q

Peroxisomes

A

Hydrogen peroxide containing organelle responsible for beta oxidation of very long fatty acids

117
Q

Fluid Mosaic model

A

phospholipid bilayer with cholesterol and embedded proteins
exterior - hydrophilic phosphate head groups
interior - hydrophobic fatty acid carbon chains

118
Q

Cell Theory

A

1) all living things composed of cells
2) cells are the most basic unit of living things
3) cells pass info via DNA
4) cells only arise from other cells

119
Q

Bacteria by shape

A

cocci - spherical
bactilli - rod
spirilli - spiral

120
Q

Gram + vs Gram - bacteria?

A

Based on cell wall composition; gram + have peptidoglycan while gram - have smaller amounts of peptidoglycan with lipopolysaccharides

121
Q

Binary fission

A

How prokaryotes divide/reproduce

122
Q

Stages of cell cycle

A

G1 - cell increases in organelles and cytoplasm
S - DNA replication
G2 - same as G1
M - mitosis/division

123
Q

Acronym for Mitosis

A

PMAT

124
Q

Meiosis important steps

A

P1 - two pairs of sister chromatids form tetrads *crossing over can occur
M1 - homologous chromosomes separate
PMAT2 - identical to mitosis except no replication

125
Q

When does meiosis occur?

A

Spermatogenesis and oogenesis

126
Q

Four stages of early embryonic development

A

cleavage - mitotic divisions
implantation - embryo implants during blastula stage
gastrulation - ectoderm, endoderm, and mesoderm form
neurulation - germ layers develop a nervous system

127
Q

Ectoderm

A

Top germ layer and “attract” oderm

Hair, skin, nails, brain, lens of eye, inner ear

128
Q

Mesoderm

A

Middle germ layer and “muscle”derm

Muscles, skeleton, circulatory system, gonads, kidneys

129
Q

Endoderm

A

Lower germ layer and “endernal organs”

Lining of the digestive tract, lungs, liver and pancreas

130
Q

Components of osmoreglation

A

Filtration - at the glomerulus, filtrate passes through

Secretion - of acids, bases, and ions from interstitial fluid to filtrate; maintains pH, [K+], and [waste]

Reabsorption - essential substances and water flow from filtrate to blood; enabled by osmolarity gradient and selective permeability of the walls

131
Q

Action of aldosterone

A

Stimulated Na+ reabsorption and K+ and H+ secretion, increasing water reabsorption, blood volume, and blood pressure

Secreted from adrenal cortex, regulated by renin-angiotensin-aldosterone system

132
Q

Action of ADH

A

Increases collecting ducts permeability to water to increase water absorption

Secreted from posterior pituitary with when high [solute] in blood

133
Q

Livers roles in homeostasis

A

1) gluconeogenesis
2) processing of nitrogenous wastes (urea)
3) detoxification of wastes/chemicals/drugs
4) storage of iron and vitamin A
5) synthesis of bile and blood proteins
6) beta oxidation of fatty acids to ketones
7) interconversion of carbohydrates, fats, and amino acids

134
Q

Anterior Pituitary Hormones

A

FSH - stimulates follicle maturation, spermatogenesis
LH - stimulates ovulation; testosterone synthesis
ACTH - stimulates adrenal cortex to make and secrete glucocorticoids
TH - stimulates thyroid to produce thyroid hormones
Prolactin - stimulates milk production and secretion
Endorphins - inhibits perception of pain
GH - stimulates bone and muscle groups/lipolysis

135
Q

Posterior Pituitary Hormones

A

*produced in hypothalamus, stored in posterior pituitary
Oxytocin - stimulates uterine contractions during labor, milk secretion during lactation
ADH - increases blood volume/pressure by stimulating insertion of aquaporins in the collecting duct of the nephron

136
Q

Thyroid Hormones

A

T3, T4 - stimulates metabolic activity

Calcitonin - decreases blood calcium

137
Q

Parathyroid Hormone

A

Increases blood calcium

138
Q

Adrenal Cortex Hormones

A

Glucocorticoids - increase blood glucose level and decrease protein synthesis; anti-inflammatory
Mineralcorticoids - increase water reabsorption in the kidney

139
Q

Adrenal Medulla Hormones

A

Epinephrine, Norepinephrine - Increase blood glucose level and heart rate

140
Q

Pancreatic Hormones

A

Glucagon - Stimulates conversion of glycogen to glucose in the liver, increasing blood glucose
Insulin - Stimulates conversion of glucose to glycogen, lowering blood glucose and increasing glycogen stores
Somatostatin - Suppresses secretion of glucagon and insulin

141
Q

Testosterone

A

Released from the testes; maintains male secondary sex characteristics

142
Q

Hormones from Ovary/Placenta

A

Estrogen - Maintains female secondary sex characteristics

Progesterone - Promotes growth/maintenance of the endometrium

143
Q

Melatonin

A

Released from the pineal gland; regulates sleep-wake cycles

144
Q

Atrial natriuretic peptide

A

Released from the heart; involved in osmoregulation and vasodilation

145
Q

Thymosin

A

Released from the thymus; stimulates T-cell development

146
Q

Menstrual Cycle Stages

A

1) Follicular - FSH causes growth of the follicle
2) Ovulation - LH causes follicle to release egg
3) Luteal - Corpus luteum forms
4) Menstruation - endometrial lining sheds

147
Q

How is the RMP of neurons maintained?

A

Na/K ATPase pumps 3 Na+ out for 2 K+ in

148
Q

Action Potential

A

Stimulus acts on the neuron, depolarizing the membrane of the cell body

149
Q

Impulse propogation

A

Depolarization (Na+ rushes into the cell) followed by repolarization (K+ rushes out of the cell) along the axon

150
Q

Action at the synapse

A

1) At the synaptic terminal, voltage-gated Ca++ channels open sending Ca++ into the cell
2) Vesicles fuse with the synaptic membrane, releasing NTs into the synaptic cleft
3) NTs bind to receptors on the post synaptic membrane, triggering depolarization

151
Q

Neuron channel statuses at different stages of AP

A

Rest - All gates closed
Depolarization - Na+ gates open
Repolarization - Na+ gates inactivated, K+ gates open
Hyperpolarization - All gates closed

152
Q

What is the sarcomere?

A

The contractile unit of the fibers in skeletal muscle

Spans z-line to z-line (mid point of thin actin fibers on either side of myosin fibers)

153
Q

Steps of skeletal muscle contraction

A

1) Depolarization of neuron leads to action potential
2) Sarcoplasmic reticulum releases Ca++
3) Ca++ binds to troponin on the actin filament
4) Tropomyosin shifts, exposing myosin binding sites
5) Myosin binds, ATPase activity allows myosin to pull thin filaments towards the center of the H zone, and then ATP causes dissociation
6) Ca++ is pumped back into the sarcoplamic reticulum

154
Q

Osteoblast vs Osteoclast

A

Builds vs. Breaks down bone

155
Q

Reformation (bone)

A

Inorganic ions are absorbed from the blood for use in bone

156
Q

Degradation (bone)

A

Inorganic ions are released into the blood

157
Q

Circulatory pathway through the heart

A

Superior + inferior vena cavae –> right atrium –> tricuspid valve –> right ventricle –> pulmonary artery –> lungs –> pulmonary vein –> left atrium –> bicuspid valve –> left ventricle –> aorta

158
Q

Three portal systems

A

Blood travels through an additional capillary bed before returning to the heart
Hepatic, Hypophyseal, Renal

159
Q

Fetal Circulation (different parts)

A

Foramen Ovale - connects right and left atria
Ductus arteriosus - connects pulmonary artery to aorta; shunts blood away from the lungs (along w FO)
Ductus venosus - connects umbilical vein to inferior vena cava, connecting umbilical circulation to central circulation

160
Q

Blood components

A

Plasma - aqueous mixture of nutrients, gases, wastes, hormones, blood proteins, and salts
RBCs - carry oxygen via hemoglobin
Leukocytes - immune function
Platelets - clotting

161
Q

Oxygen-hemoglobin dissociation + what causes rightward shift

A

Sigmoidal curve indicative of cooperative binding

  • incrs temp
  • bohr effect (dcrs pH, incrs PCO2): bc H+ binds allosterically to Hb enhancing release to the tissues and incrs PCO2 leads to incs H+
162
Q

Blood buffer equation

A

CO2 + H2O –> (carbonic anhydrase) –> H2CO3 –> H+ + HCO3-

163
Q

Blood clotting

A

1) Platelets release thromboplastin, which (along with cofactors and vitamin K) converts prothrombin to active thrombin
2) thrombin converts fibrinogen to fibrin, which surrounds blood cells to form a clot

164
Q

Blood Types

A

A - A antigen, anti-B antibodies
B - B antigen, anti-A antibodies
AB - A, B antigens, no antibodies; universal receiver
O - no antigens, all antibodies; universal donor

+ = yes Rh antigen, no anti-Rh antibody and vice versa

165
Q

Gas exchange in the lungs

A

1) Deoxy blood enters the pulmonary capillaries that surround the alveoli
2) O2 from inhaled air diffuses down gradient into the capillaries, where it binds to Hb and returns to the heart
3) CO2 from the tissues diffuses from the capillaries to the alveoli and is exhaled

166
Q

Fetal Respiration

A

Fetal Hb has higher affinity to O2; gas and nutrient exchange occurs across placenta

167
Q

Lipid digestion

A

1) when chyme is present, duodenum secretes CCK into the blood
2) CCK stimulates secretion of pancreatic enzymes into the bile, and promotes satiety

  • bile is made in the liver and emulsifies fat in the small intestine (NOT an enzyme)
  • Lipase is an enzyme made in the pancreas that hydrolyzes lipids in the small intestine
168
Q

Carbohydrate Digestion

A

Salivary amylase - produced by salivary glands in mouth; starch –> maltose

Pancreatic amylase - produced by pancreas, acts in small intestine; starch –> maltose

Maltase - produced by intestinal glands, acts in small intestine; maltose –> 2 glucose

Sucrase - produced by intestinal glands, acts in small intestine; sucrose –> glucose, fructose

Lactase - produced by intestinal glands, acts in small intestine; lactose –> glucose, galactose

169
Q

Protein Digestion

A

Pepsin - produced by chief cells, acts in stomach; hydrolyzes peptide bonds

Trypsin - produced in pancreas, acts in small intestine; hydrolyzes specific peptide bonds, converts chymotrypsinogen to chymotrypsin

Chymotrypsin - produced in pancreas, acts in small intestine; hydrolyzes specific peptide bonds

Carboxypeptidases A and B - produced in pancreas, acts in small intestine; hydrolyzes terminal peptide bonds at C-terminus

Aminopeptidase - produced in intestinal glands, acts in small intestine; hydrolyzes terminal peptide bonds at N-terminus

Dipeptidase - produced in intestinal glands, acts in small intestine; hydrolyzes pairs of AAs

Enteropeptidase - produced in intestinal glands, acts in small intestine; converts trypsinogen to trypsin

170
Q

Nonspecific Immune Response

A

Skin, passages lined w cilia, macrophages, inflammatory response, and interferons (proteins that prevent spread of virus)

171
Q

Humoral Immunity

A

B-lymphocytes - memory cells (remember antigen, speed up secondary response) and plasma cells (make and release antibodies which induce antigen phagocytosis)

172
Q

Cell-Mediated Immunity

A

T-lymphocytes - cytotoxic T-cells (destroy cells directly), helper T-cells (activate B and T cells and macrophages by secreting lymphokines), and suppressor T-cells (regulate B and T cells to decrease anti-antigen activity)

173
Q

Organization of lymphatic system

A

1) Lymph vessels meet at the thoracic duct in the upper chest and neck, draining into the left subclavian vein
2) vessels carry lymph (excess interstitial fluid) and lacteals collect fats by absorbing chylomicrons in the small intestine
3) lymph nodes are swellings along the vessels with phagocytic cells (leukocytes); remove foreign particles from the lymph

174
Q

Law of Segregation

A

Homologous alleles (chromosomes) separate so that each gamete has one copy of each gene

175
Q

Law of Independent Assortment

A

Alleles of unlinked genes assort independently in meiosis

*for two traits: AaBb parents will produce AB, Ab, aB, and ab gametes and the phenotypic ratio for this cross is 9:3:3:1

176
Q

Probability of genotype that requires multiple events to occur

A

Product of probability of each event

177
Q

Probability of genotype that can be the result of multiple different events

A

Sum of probability of each event

178
Q

How can genes be unlinked?

A

Crossing over during prophase of meiosis I.

179
Q

Determine recombinant frequencies?

A

How many map units apart are the two genes

180
Q

Autosomal recessive

A

skips generations

181
Q

Autosomal dominant

A

appears in every generation

182
Q

X-linked

A

no male-to-male transmission and more males are affected

183
Q

Hardy Weinberg equilibrium

A

When populations are stable: no mutations, large population, random mating, no migration, and equal reproductive success

p^2 + 2pq +q^2 = 1; p + q = 1

184
Q

Operon Genes

A

structural - contains DNA that codes for a protein
promoter - binding site of RNA polymerase
operator - binding site for repressor

185
Q

Inducible vs Repressible Systems

A

Inducible systems need an inducer for transcription to occur, repressible systems need a corepressor for transcription to stop

186
Q

Virus

A

Acellular structure of double- or single- stranded DNA or RNA in a protein coat

187
Q

Lytic vs Lysogenic Cycles

A

Lytic - virus kills host cell

Lysogenic - virus enters host genome

188
Q

Plasmids

A

Extragenomic material found in most bacteria; if can be integrated into the genome = episomes

189
Q

Transformation (bacteria)

A

When bacteria incorporates genetic material from the environment into host cell genome; antibiotic resistance

190
Q

Conjugation

A

Bacterial mating - two cells form a cytoplasmic bridge (made from sex pili, only on donor males with sex factors) between them allowing for transfer of genetic material (one way from male to female)

191
Q

Transduction

A

Transfer of genetic information from bacterium to bacterium via infection with bacteriophages

MCAT (5 decks)

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