Bio/Biochem

Question 1

im·mu·no·as·say

Answer 1

a procedure for detecting or measuring specific proteins or other substances through their properties as antigens or antibodies

Question 2

immunoassay

Answer 2

An immunoassay is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes)

Question 3

what is ELISA?

Answer 3

enzyme-linked immunosorbent assay, an immunological assay technique making use of an enzyme bonded to a particular antibody or antigen

Question 4

Direct ELISA Assay

Answer 4

The surface of the plate is coated directly with the sample. An enzyme-tagged antibody enables its measurement

Question 5

Indirect ELISA Assay

Answer 5

Indirect ELISA is a two-step binding process involving the use of a primary antibody and a labeled secondary antibody

Question 6

Competitive ELISA

Answer 6

In competitive enzyme immunoassays, the antigen in a sample competes for limited antibody binding sites with antigen conjugated to a reporter enzyme. This produces an inverse relationship between antigen concentration and substrate turnover. Competitive ELISAs typically use a single antibody to a low molecular weight antigen

Question 7

capture assay

Answer 7

an enzyme immunoassay using two antibodies; the first binds the antigen to solid phase, and the second contains the enzyme label and acts as an indicator

Question 8

A low NAD+/NADH ratio drives what?

Answer 8

having more reduced NADH (NAD+) drives fatty acid synthesis because NAD+ is used to generate ATP which is required for fatty acid synthesis

Question 9

Tollen’s reagent

Answer 9

Tollen’s reagent is an oxidizing agent used to determine the presence of aldehydes and ketones *add functional groups to quizlet

Question 10

DNA stop codons

Answer 10

TAA, TAG, TGA

Question 11

RNA stop codons

Answer 11

UAA, UAG, UGA

Question 12

add amino acids

Answer 12

amino acids

Question 13

this amino acid can be used for gluconeogenesis

Answer 13

proline

Question 14

Where does the Krebs cycle (also TCA cycle and citric acid cycle) occur?

Answer 14

mitochondrial matrix (inside)

Question 15

Krebs Cycle (Citric Acid Cycle)

Answer 15

The Krebs Cycle, also known as the citric acid cycle, takes place in the matrix of the mitochondria. In the Krebs Cycle, each of the two acetyl coenzyme A molecules enter the cycle and combine with oxaloacetate to form citric acid, which then loses two carbons as carbon dioxide. The cycle is now ready to begin again with the second Acetyl CoA. For each Acetyl CoA, the Krebs Cycle produces 1 ATP, 3 NADH, and 1 FADH2.

Question 16

Krebs cycle

Answer 16

breaks down glucose following glycolysis (which occurs in the cytoplasm)

Question 17

Pyruvate

Answer 17

Three-carbon compound that forms as an end product of glycolysis. 2 pyruvate for each glucose

Question 18

pyruvate has to be actively transported

Answer 18

from cytoplasm to matrix for krebs cycle

Question 19

pyruvate dehydrogenase

Answer 19

converts pyruvate to acetyl-CoA (which then enters the krebbs cycle) - stimulated by insulin - inhibited by acetyl-CoA

Question 20

Acetyl CoA

Answer 20

is a precursor for fatty acid synthesis and is generated in the mitochondria but enzymes for FA synthesis are in the cytoplasm so acetyl coA has to be changed into citrate to be transported beck into cytoplsm transforming citrate back to acetyl coA generates acetyl coA and oaxaloacetate (which can be changed into pyruvate which can be used for glycolysis)

Question 21

NADPH

Answer 21

reducing agent to help with anabolic reactions

Question 22

anabolic

Answer 22

building up (uses ATP)

Question 23

cofactor

Answer 23

A nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors, mostly metal ions or coenzymes, are inorganic and organic chemicals that assist enzymes during the catalysis of reactions

Question 24

ATP hydrolysis

Answer 24

energy released, loses phosphate

Question 25

fatty acid oxidation

Answer 25

Fatty acid oxidation is the mitochondrial aerobic process of breaking down a fatty acid into acetyl-CoA units

Question 26

add all orgo functional groups

Answer 26

orgo functional groups

Question 27

Isomer

Answer 27

Compounds with the same formula but different structures.

Question 28

amino acid residue

Answer 28

an amino acid in a polypeptide that is not the N or C terminal AA. This refers to every amino acid in a polypeptide chain.

Question 29

fructose has a

Answer 29

ketone (is a ketose)

Question 30

glucose, galactose, and ribose are all

Answer 30

aldoses

Question 31

aldehydes are more reactive to oxidation than

Answer 31

ketones

Question 32

Pyrimidines

Answer 32

Cytosine and Thymine

Question 33

visualization of an antigen of interest in an immunoassay requires labeling of antibodies with…

Answer 33

1. flourophores 2.enzymes 3. radioisotopes 4.biotin 5.small peptides NOT large proteins like Albumin

Question 34

transmembrane proteins

Answer 34

two hydrophilic portions and one hydrophobic portion, provide about 50% of the drug targets

Question 35

monotopic proteins

Answer 35

only on one side of the membrane

Question 36

globular proteins

Answer 36

these are compact, generally rounded, and soluble in water.

Question 37

fibrous proteins

Answer 37

long, insoluble, structural proteins.

Question 38

The reduced form

Answer 38

a gain of H bonds and a decrease in oxidation state

Question 39

tertiary structure of protein

Answer 39

Defined by the hydrophilic, ionic and hydrophobic interactions between R groups of amino acid chains.

Question 40

secondary structure of protein

Answer 40

alpha helix and beta pleated sheet, determined by H bonds

Question 41

primary structure of protein

Answer 41

the amino acid sequence of the polypeptide chain

Question 42

phosphate groups

Answer 42

negatively-charged groups that store the energy in ATP -found in ATP, ADP, and DNA/RNA backbone

Question 43

Testosterone

Answer 43

steroid hormone, not charged, can pass through the plasma membrane

Question 44

amine hormone

Answer 44

Amino acids with modified groups Ex. Norepinephrine

Question 45

peptide/protein hormones

Answer 45

-Chains of amino acids -short-acting -promote second-messenger cascades -soluble in water (polar) ex. oxytocin

Question 46

protein hormone

Answer 46

long chains of linked amino acids ex. human growth hormone

Question 47

steroid hormones

Answer 47

-derived from cholesterol, nonpolar -share cholesterol’s fused-ring hydrocarbon structure -signaling molecules that bind to their receptors in the nucleus and impact transcription ex. testosterone, progesterone, estrogen

Question 48

Histone

Answer 48

protein molecule around which DNA is tightly coiled in chromatin histones are usually positively charged which attracts them to to the negative DNA backbone

Question 49

ATP hydrolysis

Answer 49

releases energy because the ATP structure is unstable because of the close phosphate groups

Question 50

insulin

Answer 50

A peptide/protein hormone (made of amino acids aka polar) produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body, especially the liver and muscle, and allows them to take glucose out of the blood (thus lowering blood glucose levels).

Question 51

memmorize all the

Answer 51

amino acids

Question 52

pyrimidines

Answer 52

can be metabolized into malonyl-coA by being fed into the citric acid cycle and used to generate NADH/FADH2

Question 53

ketogenic amino acids

Answer 53

leucine and lysine -meaning they do not produce intermediates that can be converted to glucose

Question 54

glucogenic amino acids

Answer 54

amino acids that can be used to form glucose They are: A, R, N, D, C, E, G, H, V, M, P, and S DARN CHEG VMPS

Question 55

formation of a disulfide bond occurs through

Answer 55

oxidation

Question 56

a carbonyl carbon is a classic ______________ due to the electron withdrawing effect of the double-bonded carbonyl oxygen

Answer 56

electrophile

Question 57

______ is the nucleophile that attacks during the peptide bond formation

Answer 57

the amino terminal nitrogen

Question 58

things used to denature proteins:

Answer 58

1. heat 2.pH 3.inorganic salt solution (an enzymatic inhibitor would not be used to denature a protein)

Question 59

look up gabriel synthesis

Answer 59

involves sn2 mechanism (look up diff between sn1 and sn2)

Question 60

SN1 and SN2 https://www.masterorganicchemistry.com/2012/08/08/comparing-the-sn1-and-sn2-reactions/

Answer 60

SN1 involves carbocation formation which is the rate-limiting step, nucleophile can attack on either plane of sp2 C, so both enantiomers can form SN2 involves backside attack, so inversion of configuration with pentavalent transition state unimolecular nucleophilic substitution (SN1), whereby the rate determining step is unimolecular and bimolecular nucleophilic substitution (SN2), whereby the rate determining step is bimolecular SN1 on 2/3 degree carbons only (carbocation stability!), SN2 on 0/1/2 degree carbons only SN1 considerations: 1. doesn’t consider nucleophile size/conc. in rate law 2. polar, protic solvent 3. 2/3 degree carbons only SN2 like polar, aprotic solvents: acetone, DMF, DMSO alcohols and ethers undergo substitution only with an acid catalyst or conversion to a better leaving group (something resonance stabilized maybe) “Protic” Solvents Have O-H or N-H Bonds And Can Hydrogen-Bond With Themselves. “Aprotic” Solvents Cannot Be Hydrogen Bond Donors

Question 61

catalytic site

Answer 61

reduces chemical activation energy

Question 62

orthosteric regulation

Answer 62

regulator binds in active site

Question 63

allosteric regulation

Answer 63

regulator binds at non-active site

Question 64

oxidoreductases

Answer 64

catalyze oxidation-reduction reactions ex. alcohol dehydrogenase superoxide dismutase

Question 65

transferases

Answer 65

transfer functional groups between molecules ex. aspartate transaminase creatine kinase DNA polymerase

Question 66

hydrolases

Answer 66

catalyze hydrolysis ex. angiotensin-converting enzyme pancreatic lipase lactase

Question 67

lyases

Answer 67

cleave bonds through non-hydrolysis mechanisms ex. pyruvate decarboxylase aconitase

Question 68

isomerases

Answer 68

catalyze isomerization ex. ribose-5-phosphate isomerase

Question 69

ligases

Answer 69

join molecules together with covalent bonds ex. aminoacyl tRNA synthetase glutamine synthetase pyruvate carboxylase

Question 70

phosphatases _______ phosphate groups, while kinases_______ phopshate groups

Answer 70

remove, add

Question 71

cooperativity

Answer 71

It amplifies the response of enzymes to substrates, sigmoidal curve

Question 72

Hill coefficient

Answer 72

A measure of cooperative interaction between protein subunits if >1 then binding of each ligand is easier and positive cooperativity if <1 then binding of each successive ligand is harder and negative cooperativity (inhibition)

Question 73

Km constant in the Michaelis-Menten equation

Answer 73

the concentration of substrate that corresponds to half of vmax (max velocity of the reaction)

Question 74

michaelis-menton equation

Answer 74

V=Vmax[S]/Km+[S]

Question 75

Km is important because

Answer 75

it can be used as a measure of the affinity that an enzyme has for its substrate

Question 76

km is not affected by _______ but is affected by __________

Answer 76

not: the concentration of the substrate or enzyme Is: inhibitors

Question 77

competitive inhibitors

Answer 77

-compete with the substrate -do NOT affect Vmax because by adding more substrate you can minimize the effect of the competitive inhibitor -DO affect Km because their effects can be neutralized with extra substrate, but adding the extra substrate requires more substrate to reach half of Vmax, which by definition means increasing Km

Question 78

noncompetitive inhibitors

Answer 78

-interact with the enzyme allosterically -essentially prevent the enzyme from working -effect is similar to reducing the concentration of the enzyme that is present -DOES reduce Vmax -does NOT affect Km because the molecules of enzyme that are not affected by the noncompetitive inhibitor remain functional

Question 79

uncompetitive inhibitors

Answer 79

-interact with the enzyme-substrate complex at an allosteric site, essentially prevent an enzyme from letting go of a substrate that it has bound -Vmax decreases bc the overall rate of the catalyzed reaction is reduced -decrease in Km because the stabilization of the E-S complex effectively means that the enzyme seems to have a greater affinity for the substrate

Question 80

mixed inhibition

Answer 80

-inhibitor can either -can bind the free enzyme at an allosteric site or can bind the E-S complex -Vmax is always decreased -its effect on Km depends on the binding preference of a given inhibitor if prefers binding to E-S complex: similar to an noncompetitive inhibitor so Km will be decreased if prefers binding to the free enzyme at an active site (allosteric I think)**??? then Km is increased tim said: The correct answer is that a mixed inhibitor may bind the active site of the free enzyme (like a competitive inhibitor) or to an allosteric site on the enzyme-substrate complex (like an uncompetitive inhibitor (note: not the same as a non-competitive inhibitor). Depending upon the inhibitor’s “preference” for binding free E or E-S complex, you will get an effect that “mimics” a competitive or non-competitive inhibitor.

Question 81

phosphorylation most commonly targets

Answer 81

serine, threonine, and tyrosine which all have -OH groups that the phosphate group can be attached to

Question 82

zymogens or proenzymes

Answer 82

are produced in their inactive form and can be activated by cleavage at a later time when they are needed

Question 83

cofactors or coenzymes (organic cofactors)

Answer 83

are required for the enzyme to be activated

Question 84

Kinetic efficiency

Answer 84

a measure of how efficiently an enzyme converts substrates into product Kcat/Km highest ratio=highest efficiency

Question 85

homogenate

Answer 85

a mixture of all of the components of the cell, but no intact cells.

Question 86

Warberg effect

Answer 86

cancer cells rely on anaerobic glycolysis instead of ox phos (more efficient) to generate energy

Question 87

primary active transport

Answer 87

Active transport that relies directly on the hydrolysis of ATP.

Question 88

secondary active transport

Answer 88

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

Question 89

Microfilaments

Answer 89

Long, thin fibers that function in the movement and support of the cell

Question 90

Microtubules

Answer 90

Spiral strands of protein molecules that form a tubelike structure

Question 91

intermediate filaments

Answer 91

A component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments.

Question 92

antibody IgA

Answer 92

-present in mucosal areas such as the gut, respiratory tract, saliva, tears, breast milk, and the urogenital tract, -it helps prevent colonization by pathogens

Question 93

antibody IgD

Answer 93

-principally acts as an antigen receptor on B cells that have not been exposed to antigens -it is involved in the activation of mast cells and basophils

Question 94

antibody IgE

Answer 94

-involved in allergies and anti-parasitic responses -IgE binds to allergens, causing histamine release from activated mast cells and basophils

Question 95

antibody IgG

Answer 95

-four forms of IgG provide most of the humoral immune response -it is the only antibody type capable of crossing the placenta and conferring passive immunity to a developing fetus

Question 96

antibody IgM

Answer 96

-the first antibody secreted upon exposure to an antigen -responsible for mounting an immune response and eliminating pathogens in the early stages of the humoral response, before IgG levels increase -it is expressed on the surface of B cells as a monomer and is secreted by plasma cells as a pentamer

Question 97

CAMs

Answer 97

cell adhesion molecules

Question 98

Cytokines

Answer 98

-Chemicals released by the immune system communicate with the brain. -signaling molecules of the immune system

Question 99

motor protein: Kinesins

Answer 99

move towards the (+) end of microtubules (towards the periphery), transport vessicles and organelles by travelling along microtubules, which requires the hydrolysis of ATP

Question 100

motor protein: dyneins

Answer 100

carry cargo xtowards the (-) end of microtubules (towards center)

Question 101

motor protein: myosin

Answer 101

involved in muscle contractions, use ATP to carry out power stroke

Question 102

antibodies

Answer 102

-glycoproteins that recognize antigens (characteristic regions, usually of foreign objects/substances) -composed of at least one immunoglobulin (Ig) unit, each of which has two heavy chains and two light chains, forming a Y shape -several types exist; most important are IgM antibodies, which respond to acute infections, and IgG antibodies, which help confer lasting immunity

Question 103

cell adhesion

Answer 103

proteins involved include selectins, cadherins, and integrins

Question 104

cell adhesion: anchoring junctions

Answer 104

involve cadherins, help keep cells/tissues in place

Question 105

cell adhesion: gap junctions

Answer 105

formed by connexin proteins, connect cells in a way such that diffusion/communication can take place between them

Question 106

cell adhesion: tight junctions

Answer 106

involve several types of proeteins, are found in epithelial cells, and prevent solutes from being able to move freely from one tissue into another classic example: blood-brain barrier

Question 107

ion channel-linked receptors:

Answer 107

-also known as ligand-gated ion channels -change shape in response to binding with a ligand to open and let ions through

Question 108

enzyme-linked receptors

Answer 108

-either enzymes themselves, or are directly associated with the enzymes that they activate -majority are protein kinases, and regulate many normal cellular processes

Question 109

G protein-coupled receptors

Answer 109

-composed of three distinct alpha, beta, and gamma subunits -they become activated by binding with GTP -the alpha subunit together with the bound GTP dissociates from the beta and gamma subunits, which interact with other signaling processes in the cell (secondary pathways)

Question 110

nuclear receptors

Answer 110

-found within the cell (either on the nucleus or in the cytosol before travelling to the nucleus) and regulate gene transcription in response to binding with a signaling molecule (often a steroid hormone)

Question 111

specificity constant of the interaction between two molecules

Answer 111

kcat/km

Question 112

Kcat

Answer 112

turnover number (molecules catalyzed per second in optimal conditions) Vmax / [E]

Question 113

actin filaments

Answer 113

can be assembled in a branched pattern (while microtubules cannot)

Question 114

Goldberg-Hogness box (TATA box)

Answer 114

A short nucleotide sequence 20-30 bp upstream from the initiation site of eukaryotic genes to which RNA polymerase II binds. The consensus sequence is TATAAAA. Also known as a TATA box. promoter for transcription

Question 115

kinetochore

Answer 115

-protein complex assembled at each centromere -serves as an attachment site for spindle microtubules and the site at which motors generate forces to power chromosome movement

Question 116

spindle poles

Answer 116

ends of spindles (specialized microtubules that captures and separates chromosomes)

Question 117

centriole

Answer 117

Made of bundles of long filaments called microtubules that help in organizing cell division, radiate in star-shaped clusters known as asters which help align chromosomes during cell division

Question 118

Centromere

Answer 118

Area where the chromatids of a chromosome are attached

Question 119

Immunoglobulin M (IgM) contains

Answer 119

two heavy chains and two light chains

Question 120

cadherins

Answer 120

cell adhesion molecules that comprise adherens junctions and serve to connect cells to eachother (transmembrane proteins)

Question 121

dyneins

Answer 121

require ATP, involved in retrograde transport of cargo (movement towards center of the cell)

Question 122

G proteins

Answer 122

activated by substitution of GDP for GTP, but deactivated when GTP is hydrolyzed to GDP by GTPase

Question 123

look up a video on titration

Answer 123

each half equivalence point signifies a functional group

Question 124

look up cation exchange chromatography

Answer 124

In cation-exchange chromatography, positively charged molecules are selectively purified via binding to an anionic solid phase. Thus, for this amino acid to be purified in this manner, it must have a net positive charge. adding more base means the unknown amino acids will be less positive, just as a concept

Question 125

linking of amino acids

Answer 125

Polypeptides are formed via dehydration synthesis reactions that link amino acids with peptide bonds. The incoming amino group acts as a nucleophile and attacks the carbonyl carbon, and the labeled hydrogen molecule (along with the O to which it is directly bound) is released as water.

Question 126

ion exchange chromatography

Answer 126

Ion-exchange chromatography separates compounds based on net charge. In this case, the stationary phase is negative, meaning that positive compounds will be retained in the column. In other words, these species will elute more slowly because they will interact more with the stationary phase. Therefore, we would expect the polypeptide that elutes first to contain fewer positively-charged residues than the one that elutes second. Arginine (R) is positively charged at physiological pH, so it is unlikely to be common in the polypeptide referenced.

Question 127

protein tertiary structure

Answer 127

Tertiary structure is driven by the tendency of hydrophobic residues to bury themselves inside the protein, away from aqueous environments, as well as side chain interactions such as hydrogen bonding and disulfide bridges. We can therefore expect that a substitution between amino acids that vary in polarity, charge, or sulfur content might change this level of structure. Of all the replacements listed, exchanging glycine (a nonpolar, neutral residue that lacks sulfur) with cysteine (a polar AA with the ability to participate in disulfide bridges) is most likely to cause a change in tertiary structure.

Question 128

the only amino acid that can for disulfide bonds is… because it has…

Answer 128

cystein, a free -SH group

Question 129

look up what makes something aromatic

Answer 129

Aromatic compounds are those that contain planar, conjugated rings and follow Hückel’s rule, which stipulates that the system must possess 4n + 2 π electrons. (To simplify this rule, remember that “n” denotes any integer, meaning that aromatic systems may contain 6, 10, or 14 π electrons, and so on.) Tyrosine, a classic example of an aromatic amino acid, fits all of these qualifications.

Question 130

enzymes affect the ______ not the _______ of a reaction

Answer 130

kinetics, thermodynamics

Question 131

spontaneous v non spontaneous reactions

Answer 131

As a rule of thumb, remember that exergonic reactions (ΔG < 0) are spontaneous, while endergonic processes (ΔG > 0) are nonspontaneous

Question 132

energy-rich compunds

Answer 132

ATP, creatine phosphate, and acetyl-CoA are all similar in that they contain high-energy phosphate or thioester bonds. used to couple to and drive nonspontaneous reactions

Question 133

second law of thermodynamics

Answer 133

he second law of thermodynamics states that a spontaneous reaction or cyclic process must yield a net entropy increase.

Question 134

first law of thermodynamics

Answer 134

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 135

Third Law of Thermodynamics

Answer 135

The entropy of a perfect crystal is zero when the temperature of the crystal is equal to absolute zero (0 K).

Question 136

Gibbs free energy

Answer 136

ΔG = ΔH - TΔS, where ΔH represents the change in enthalpy, T denotes Kelvin temperature, and ΔS denotes the change in entropy.

Question 137

ATP equivalents of NADH and FADH2

Answer 137

NADH=2.5ATP FADH2=1.5ATP (because FADH2 enters the ETC one complex later than NADH)

Question 138

Enantiomers

Answer 138

isomers that are mirror images of each other, but not superimposable

Question 139

which enantiomer is present in the human body

Answer 139

L

Question 140

Anion exchange chromatography

Answer 140

Negative proteins stick to positive beads, only positive proteins go through (name describes what it captures/what elutes last)

Question 141

pI

Answer 141

net charge of a protein will be zero

Question 142

SDS-PAGE

Answer 142

Type of chromatography used to separate proteins based on mass.

Question 143

Beer-Lambert Law relationship between absorbance, extinction coefficient, concentration, and path length

Answer 143

absorbance = εCL. Here, ε represents the extinction coefficient, C denotes the concentration of the solution, and L stands for the path length in centimeters

Question 144

SDS-PAGE

Answer 144

breaks up proteins into its subunits

Question 145

critical pont

Answer 145

the the concentration where the length of the polymer is sable (no net polymerization or depolarization occurs)

Question 146

the ___ ends of actin molecules display stronger intermolecular interactions than the ______ ends

Answer 146

ERROR!

Question 147

microtubules originate from

Answer 147

microtubule-organizing centers, or MTOCs, these structures anchor the minus end of the microtubule to prevent depolymerization, they aslo form the origin of the spindle aparatus during cell division

Question 148

variable region of antibody

Answer 148

-antigen binding site, is specific to the antigen -includes the ends of the light and heavy chains

Question 149

constant region of an antibody

Answer 149

the constant region determines the mechanism used to destroy antigen, this region can be recognized by other immune components to further stimulate the response to a pathogen

Question 150

dynein transport

Answer 150

-travel toward the center of the cell -move toward the minus ends of the associated microtubules -are involved in retrograde transport

Question 151

vitamin E

Answer 151

antioxidant. Essential for protection of cell structure, especially of red blood cells

Question 152

vitamin A

Answer 152

regulator of tissue growth

Question 153

Vitamin B

Answer 153

The B vitamins are the largest group of vitamins and function in the production of multiple cofactors. Biotin is a B vitamin that acts as an important coenzyme, while riboflavin serves as a structural part of the cofactors FMN and FAD

Question 154

Vitamin D

Answer 154

influence over bone growth and calcium regulation

Question 155

NAD is a

Answer 155

Coenzyme Coenzymes are a subset of cofactors that tend to bind loosely to their associated enzymes. This type of molecule is also known for transferring functional groups between species. NAD serves this function by donating its hydrogen to Complex I, which is one of the four protein complexes responsible for generating the proton gradient during aerobic cellular respiration.

Question 156

prosthetic groups

Answer 156

small molecules permanently attached to the enzyme, tightly bound

Question 157

Km

Answer 157

is simply the substrate concentration at which reaction rate is equal to one-half of the Vmax

Question 158

disulfide linkages are cleaved exclusively via

Answer 158

oxidation/reduction reactions

Question 159

SDS (of SDS-PAGE)

Answer 159

disrupts secondary and tertiary protein structure and applies a uniform negative charge across the protein

Question 160

immunoaffinity

Answer 160

uses antibody-protein affinity to retain the desired substrate on the solid phase matrix

Question 161

salting in

Answer 161

-refers to the addition of salt to a solution that does not yet contain very high salt concentrations -the salt interacts with charged amino acid side chains, reducing the protein’s ability to aggregate with other proteins -the net result is increased protein solubility

Question 162

the presence of _______ amino acids in a protein cause the protein to absorb ultraviolet light whose wavelength range is: the aromatic amino acids are:

Answer 162

aromatic, 200-400nm Tyr, Trp, Phe

Question 163

in cation exchange chromatography, ______ will elute first

Answer 163

anions -the stationary phase is designed to attract cations (so it is comprised of anions)

Question 164

transition state

Answer 164

it is always is a higher energy state than the reactants or products. Thus any time the transition state is stabilized, activation energy (which by definition is the energy required to reach the transition state) is reduced. The more stable a transition state is, the less energy is required to reach it which makes it easier to go from the reactants to the final product.

Question 165

Angiotensinogen

Answer 165

• zymogen precursor to angiotensisn, a peptide hormone that leads to vasoconstriction -produced in the liver

Question 166

make flashcards for these:

Answer 166

FLAG TOP, PAVO, PIGS, ACAC, and THC. FLAG TOP for things coming from anterior pituitary (Fsh, Lh, Acth, Growth Hormone, Tsh, MelOncyte stimulating hormone, prolactin) for posterior pituitary I remember PAVO (Posterior, Adh/Vasopressin, Oxytocin) for the pancreas I remember PIGS (Pancreas, Insulin, Glycogen, Somatostatin) for the thyroid I remember THC like in marijuana (Thyroid Hormone, Calcitonin) and for adrenal cortex I remember ACAC (Adrenal Cortex, Aldosterone, Cortisol)

Question 167

make flashcards for these hormones

Answer 167

These are all the hormones that must be memorized for the MCAT. Learn the 5 steroid and know the rest are protein, know where there are secreted from (in the case of oxytocin and vasopressin (or antidiuretic hormone) know they are made in the hypothalamus and secreted to the posterior pituitary where they are stored and later secreted.Steroid:Testosterone (Androgen): TestesProgesterone: Ovary specifically corpus luteumEstrogen: ovary specifically follicleAldosterone: adrenal cortexCortisol: adrenal cortexProtein:Follicle stimulating hormone: anterior pituitaryLeutinizing hormoneACTHThyroid stimulating hormone (TSH)ProlactinGrowth hormoneOxytocin: posterior pituitaryVasopressinInsulin: pancreasGlucagonParathyroid hormone: parathyroidCalcitonin: thyroidThyroxineEpinephrine: Adrenal MedullaNorepinephrine

Question 168

hypophyseal portal system

Answer 168

blood leaving capillary beds in hypothalamus travels to a capillary bed in anterior pituitary to allow for paracrine secretion of releasing hormones

Question 169

-dioic acid

Answer 169

2 carboxylic acids

Question 170

epimers

Answer 170

are carbohydrates which differ in their configuration of a single chirla center

Question 171

memorize carbohydrates on pg16 of bio

Answer 171

there is a chart

Question 172

Tollen’s reagent, like Benedict’s reagent, is used to

Answer 172

test for reducing sugars (it oxidizes an aldehyde into a carboxylic acid) Reducing sugars have free aldehyde groups that can be oxidized to caroxylic acids, which reduces the tollens reagent to elemental silver

Question 173

Anomers

Answer 173

specific category of epimers, which are stereoisomers that differ in only one chiral center (ex. in solution glucose readily undergoes mutarotation between its alpha and beta anomers)

Question 174

specific rotation

Answer 174

-an experimental value -generally, the specific rotation of a particular compound does not relate in any predictable way to that of another compound except enantiomers have equal but opposite specific rotation values and racemic solutions have a specific rotation of 0 degrees

Question 175

Fisher Projection

Answer 175

horizontal=out of the paper vertical= into the paper

Question 176

enzymes have chiral active sites so

Answer 176

if D-glucose is normally acted on by an enzyme, that enzyme could not work on L-glucose

Question 177

hemiacetal

Answer 177

A functional group that contains a carbon atom bonded to one -OR group, one -OH group, an alkyl chain, and a hydrogen atom.

Question 178

pyranose v furanose

Answer 178

six-membered rings=pyranoses five-membered rings=furanoses

Question 179

anomer

Answer 179

A sugar diastereomer differing only in the position of the hydroxyl at the anomeric carbon (the one attached to the OH)

Question 180

glycosidic bond

Answer 180

A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.

Question 181

peptidoglycan

Answer 181

A protein-carbohydrate compound that makes the cell walls of bacteria rigid, consists of carbohydrates that have been modified with amino acids

Question 182

Chitin

Answer 182

Polysaccharide found in arthropod exoskeletons and fungal cell walls.

Question 183

optical rotation of light

Answer 183

d/l or +/-

Question 184

absolute configuration

Answer 184

-R/S -determined by the 3D arrangement of the groups attached to the chiral carbon

Question 185

comparing longer-chain carbohydrates to the three-carbon substance glyceraldehyde

Answer 185

D/L (different than the d/l system and does not have anything to do with how light is rotated)

Question 186

D/L

Answer 186

-any carbohydrate in which the bottom most -OH in the Fisher projection is pointing right is D and pointing left is L -most carbohydrates in living organisms are D isomers

Question 187

the alpha helical structure of a protein is held together by which of the following?

Answer 187

hydrogen bonding between carbonyl oxygen and amino hydrogen atoms

Question 188

Squalene

Answer 188

-is a terpene, or a compound composed of isoprene (C5H8) units -do not contain oxtgens -precursor to cholesterol

Question 189

family of receptors that allow glucose into the cells

Answer 189

GLUT receptors

Question 190

GLUT 1

Answer 190

receptor that allows glucose into the cell -is expressed throughout the body and is responsible for constant low-level baseline glucose intake

Question 191

GLUT 2

Answer 191

receptor that allows glucose into the cell -expressed by liver, pancreatic beta, and kidney cells -bidirectional transporter (both in and out of the cell)

Question 192

Bacterial cells ______ carry out post-transcriptional modification of mRNA.

Answer 192

cannot

Question 193

cDNA

Answer 193

Complementary DNA. DNA produced synthetically by reverse trascribing mRNA. Because of eukaryotic mRNA splicing, cDNA contains no inrons.

Question 194

dsDNA

Answer 194

double stranded DNA

Question 195

ssDNA

Answer 195

single stranded DNA

Question 196

all of these are true about the major groove

Answer 196

I. The major groove offers more space for the enzymes to access the sides of the bases. II. In the minor groove, the enzymes would be unable to tell the difference between an A-T and a T-A pair. III. The enzymes cannot bind to phosphate groups in the DNA backbone in a sequence-specific way

Question 197

What is the principle contributor to DNA helix stability?

Answer 197

hydrophobic effect

Question 198

Western Blotting

Answer 198

Western blotting is a technique in which proteins are run on a gel using electrophoresis, transferred to a nitrocellulose or similar membrane, and finally washed with an antibody marker. It is typically used to determine the identity of particular proteins present in a sample and can sort these proteins by molecular weight.

Question 199

Northern blots

Answer 199

detect the presence of mRNA, not protein.

Question 200

Southern blots

Answer 200

identify particular DNA sequences. The question asked about the detection of protein.

Question 201

PCR, or a polymerase chain reaction

Answer 201

is used to amplify DNA sequences of interest. It is not a detection method.

Question 202

Embryonic cells are

Answer 202

pluripotent, meaning that they can give rise to virtually any cell type found in the human body. In contrast, adult stem cells are multipotent, so their development is much more restricted. Multipotent cells can still develop into more than one cell type (for example, a variety of blood cells), but embryonic cells are still more widely useful.

Question 203

Immunohistochemistry

Answer 203

uses antibodies that are specific to proteins in an attempt to determine which antigens are expressed in a particular region of tissue. This technique has particular applications to cancer research.

Question 204

Flow cytometry

Answer 204

measures physical and chemical characteristics of cells

Question 205

restriction fragment length polymorphism (RFLP) analysis

Answer 205

providing a detailed and visual report on the protein expression within a tissue

Question 206

SDS-PAGE procedure assure that the difference in running distance on the gel is due to the length of the peptide and not its shape?

Answer 206

SDS is a detergent, meaning that it has both a hydrophobic and a hydrophilic end, like soap. This substance coats the protein and destroys hydrophobic interactions, largely denaturing all but primary structure. As a result, the protein can move through the gel in a linear fashion, removing its shape as a potential confounding variable.

Question 207

In a western blotting procedure

Answer 207

the proteins in the original mixture are first separated on an SDS-PAGE gel. Typically, in addition to SDS, a reducing agent is used to break disulfide bonds that may be present between cysteine residues. Next, antibodies are used to detect particular species.

Question 208

double check- what tim says about effector v inducer

Answer 208

There’s a subtle distinction between the two terms: from what I understand, effectors are molecules that bind to the protein and regulate its activity (aka post-translational regulation). Inducers are molecules that bind to the DNA sequence at activator or repressor sequences (aka transcriptional regulation).

Question 209

https://www.youtube.com/watch?v=vRBOv4RR7y8 shows an enhancer at work. Enhancers are DNA sequence that interact with the transcription complex to increase transcription.

Answer 209

look at video

Question 210

Glycolysis net reaction

Answer 210

Glucose + 2Pi + 2ADP + 2NAD+ -> 2pyruvate + 2ATP + 2NADH + 2H+ + 2H2O

Question 211

homolactic fermentation

Answer 211

produces lactic acid only, occurs in skeletal muscle

Question 212

heterolactic fermentation

Answer 212

produces a mixture of lactic acid, ethanol, and/or acetic acid and CO2 because the bacteria uses the branched pentose phosphate pathway instead of the standard pathway for glycolysis

Question 213

most common products of fermentation are

Answer 213

lactic acid, ethanol, methane gas, and hydrogen gas pyruvic acid is a key intermediate that is a reactant in fermentation and not a product

Question 214

Angiogenesis

Answer 214

formation of new blood vessels

Question 215

human fermentation uses:

Answer 215

lactate dehydrogenase

Question 216

alcoholic fermentation uses:

Answer 216

pyruvate decarboxylase and alcoholic dehydrogenase, produce carbon dioxide and ethanol

Question 217

aerobic respiration cannot take place if:

Answer 217

-the cell lacks sufficient final electron acceptor -the cell lacks genes to make appropriate complexes and electron carriers in the electron transport system -the cell lacks DNA to make one or more enxymes needed in the aerobic pathway (ex. citrate synthase)

Question 218

Erythrocytes

Answer 218

or red blood cells, do not contain a nucleus or mitochondria. Therefore, they cannot use the Krebs cycle or electron transport chain to create ATP

Question 219

mast cells

Answer 219

found in the connective tissue of the dermis; respond to injury, infection, or allergy by producing and releasing substances, including heparin and histamine

Question 220

In glycolysis, what is the net yield of ATP per molecule of pyruvate produced?

Answer 220

1 ATP In its entirety, one “round” of glycolysis requires two ATP molecules and produces a total of four. In other words, glycolysis forms a net quantity of two ATP molecules per original molecule of glucose. However, glucose is split into two molecules of pyruvate, the end product of the glycolytic pathway. For this reason, only one ATP molecule is made per unit of pyruvate.

Question 221

net reaction of glycolysis

Answer 221

Glucose + 2 NAD+ + 2 ADP → 2 pyruvate + 2 NADH + 2 ATP so ADP is essential for glycolysis to occur

Question 222

One hour after a meal, what is the expected saturation status of hexokinase and glucokinase with glucose?

Answer 222

Hexokinase has a much higher affinity for glucose than its isozyme, glucokinase. However, at high glucose concentrations, both enzymes should be saturated with glucose.

Question 223

Glycolysis includes three irreversible steps

Answer 223

these are catalyzed by hexokinase, phosphofructokinase, and pyruvate kinase Note that the first irreversible reaction (promoted by phosphofructokinase) is often termed the committed step, though some sources call all three steps “committed.”

Question 224

sugars that can enter glycolysis

Answer 224

glucose and fructose

Question 225

During the synthesis of malate…

Answer 225

fumarate experiences the addition of water across its double bond. This results in the replacement of this bond with an -OH group on one carbon and a hydrogen atom on the other. Such a process represents a classic hydration reaction.

Question 226

Decarboxylation

Answer 226

The complete loss of a carboxyl group as carbon dioxide

Question 227

during the krebs cycle how many NADH and FADH 2 are produced?

Answer 227

During the Krebs cycle, each unit of acetyl-CoA forms three molecules of NADH and one molecule of FADH2. In other words, the NADH-to-FADH2 ratio is 3:1.

Question 228

Throughout both the Krebs cycle and oxidative phosphorylation, how many molecules of ATP are formed per molecule of acetyl-CoA?

Answer 228

10 Acetyl-CoA is fed into the Krebs cycle to produce three NADH, one FADH2, and one GTP molecule, the last of which is immediately converted to ATP. Each NADH is later used to form 2.5 ATP molecules, while the single FADH2 unit is utilized to synthesize 1.5. In total, 12 molecules of ATP are created (counting GTP as an ATP equivalent).

Question 229

Subunits of ATP Synthase-which one rotates

Answer 229

gamma subunit rotates

Question 230

NADH enters at complex

Answer 230

I

Question 231

FADH2 enters ETC at complex

Answer 231

2

Question 232

NADH produces

Answer 232

2.5 ATP

Question 233

FADH2 produces

Answer 233

1.5 ATP

Question 234

Gluconeogenesis occurs in the

Answer 234

liver (mainly) and kidneys

Question 235

primary function of the pentose phosphate pathway

Answer 235

The primary function of the pentose phosphate pathway is to generate large quantities of NADPH for use in anabolic reactions. Without NADPH, numerous critical pathways would be hindered, including nucleic acid and fatty acid synthesis. This would directly impact the viability of the cell.

Question 236

The pentose phosphate pathway is likely most active in the

Answer 236

liver One of the primary functions of the pentose phosphate pathway is to produce NADPH, which is used in fatty acid synthesis. Fatty acid formation from carbohydrates occurs predominately in the liver

Question 237

What would be the expected effect on the pentose phosphate pathway during times of starvation

Answer 237

The starting molecule for the pentose phosphate pathway is glucose 6-phosphate. Most glucose that is ingested will be phosphorylated to form this species. During periods of starvation, glucose (both that acquired externally and that synthesized internally) is relatively unavailable. Thus, the pentose phosphate pathway should occur less frequently due to lower levels of glucose 6-phosphate.

Question 238

for MCAT a high ADP to ATP ratio or high NAD+/NADH ratio is the same as

Answer 238

needs more energy so glycolysis, citric acid cycle, and eETC are upregulated

Question 239

citric acid cycle

Answer 239

-pyruvate dehydrogenase complex (PDC) convertspyruvate to Acetyl-CoA before entering citric acid cycle (produces 1 NADH) -net producs of the citric acid cycle per turn: 1 GTP, 3NADH, 1 FADH, 2 CO2 -first step is Acetyl-CoA combining with oxaloacetate to form citrate

Question 240

ETC

Answer 240

Unlike coenzyme Q, which carries two electrons, cytochrome c carries only one electron.

Question 241

Which key intermediate of the citric acid cycle connects it with gluconeogenic pathways?

Answer 241

malate during gluconeogenesis, oxaloacetate in the mitochondria is convertes to malate for export from the mitochondria, cytosolic malate is then re-oxidized to oxaloacetate and converted to phosphophenyl pyruvate (this step is almost always rate limiting in gluconeogenesis) malate is also a citric acid cycle intermediate

Question 242

Each turn of the Krebs cycle produces

Answer 242

1 GTP ; 3 NADH ; 1 FADH2 ; two CO2 are lost as waste [it turns once for each pyruvate produced by glycolysis]

Question 243

what is the irreversible, rate-limiting step of the citric acid cycle?

Answer 243

the generation of the five-carbon molecule alpha-ketoglutarate, this step is catalyzed by the enzyme isocitrate dehydrogenase

Question 244

of protons transferred in each complex in the ETC

Answer 244

complex 1 -4 complex 2 -0 complex 3 -4 complex 4 -4 separate, but still remember: coenzyme Q- carries 2 electron cytochrome c-carries 1 electron

Question 245

What metal ion is found in cytochrome c?

Answer 245

Fe, just like in Hemoglobin

Question 246

Eicosanoids

Answer 246

lipids derived from arachidonic acid include: prostaglandins-modulate inflammation thromboxanes-involved in clotting

Question 247

LDL and HDL are not different types of cholesterol, but are rather…

Answer 247

are lipoproteins that are cholesterol transporters ldl=bad hdl=good

Question 248

Chylomicrons

Answer 248

the class of lipoproteins that transport lipids from the intestinal cells to the rest of the body

Question 249

carnitine shuttle

Answer 249

mechanism for moving fatty acids from the cytosol to the mitochondrial matrix as fatty esters of carnitine takes acyl-coA and replaces the acyl to carnitine, then restores one in matrix

Question 250

energy output of beta oxidation=

Answer 250

a little less than 7n n- number of carbons in the fatty acid chain

Question 251

fatty acid synthesis takes place in the

Answer 251

cytosol

Question 252

Fatty acid synthesis

Answer 252

ACC makes malony coA which binds to the acyl carrier protein (ACP) where the acetyl coA and malonyl coA condense to form the 4C cabone chain (this step releases CO2) then more acetyl coA parts are added and reduced, this requires NADPH (NADPH is generated by the pentose phosphate pathway)

Question 253

this enzyme catalyzes the committed step in fatty acid synthesis: the production of malonyl CoA

Answer 253

acetyl coA Carboxylase (ACC)

Question 254

Pentose Phosphate Pathway

Answer 254

A metabolic process that produces NADPH and ribose 5-phosphate for nucleotide synthesis.

Question 255

Cholesterol

Answer 255

mainly derived from diet, but can also be made de novo in the liver cholesterol synthesis is similar to fatty acid synthesis, in the first step the 6 carbon compound called mevalonate is formed from acetyl-coA molecules joining and a reduction cooupled with NADPH, this is the rate-limiting step of cholesterol synthesis summary of cholesterol synthesis: mevalonate->repeating isoprene units->squalene->cholesterol *mevalonate is the rate limiting step

Question 256

Pyruvate

Answer 256

Three-carbon compound that forms as an end product of glycolysis.

Question 257

Acetyl CoA

Answer 257

Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.

Question 258

Where does fatty acid oxidation occur?

Answer 258

mitochondria (oxidation is the breakdown)

Question 259

How do ketone bodies become ATP in the brain?

Answer 259

they are converted into acetyl-CoA which enters the TCA cycle directly

Question 260

What are the molecules in the plasma membrane made of?

Answer 260

phospholipids are made of a glycerol backbone covalently bound to two fatty acids and a phosphate group

Question 261

Where do HDL and LDL bring cholesterol?

Answer 261

LDL-transports to body tissues HDL-transports to liver

Question 262

What is sedimentation analysis?

Answer 262

sucrose and the molecule in question are centrifuged ina tube , lighter molecules move less quickly than denser molecules, each molecular type will form a discrete band at its isopycnic point, where its density equals that of the sucrose gradient

Question 263

what is the production pathways for a plasma membrane bound protein?

Answer 263

nucleus->cytoplasm->ribosome-RER-golgi

Question 264

change in G at equilibrium is…

Answer 264

0

Question 265

What is the average molecular weight of an amino acid residue?

Answer 265

110 Da a Dalton is equivalent to 1 atomic mass unit (amu)

Question 266

Which modes of transport does CO2 use in the body?

Answer 266

I. Binding hemoglobin II. Dissolving in the plasma

Question 267

What is the formula for turnover number?

Answer 267

turnover number (aka kcat) is defined as the maximum number of chemical conversions of substrate molecules per second that a single catalytic site will execute for a given enzyme concentration (ET). Turnover number can be calculated from the maximum reaction rate (Vmax) and enzyme concentration as follows: kcat = Vmax/ET

Question 268

What is homotropic regulation?

Answer 268

Homotropic regulation is when a molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzyme’s activity. O2 is a homotropic allosteric modulator of hemoglobin. The four subunits of hemoglobin actually bind to oxygen cooperatively, meaning the binding of oxygen to one of the four subunits will increase the likelihood that the remaining sites will bind with oxygen as well. causes a sigmoidal curve

Question 269

What does the hemoglobin binding curve look like and what does shifting right and left mean?

Answer 269

sigmoidal The higher the partial pressure of oxygen, the higher the oxygen saturation tends to be. Interestingly, under certain conditions, the binding curve can shift toward the right along the x-axis; this decreases the hemoglobin-oxygen binding affinity, allowing oxygen to be more easily dropped off in the tissues. These conditions include low (acidic) plasma pH and increased levels of carbon dioxide - both of which can indicate a shortage of oxygen. This rightward shift of the hemoglobin-oxygen binding curve is termed the Bohr effect. A compound known as 2,3-bisphosphoglyceric acid (2,3-BPG) can enhance these effects, further promoting the release of oxygen from hemoglobin.

Question 270

What is a suicide inhibitor?

Answer 270

an inhibitor that covalently bonds to an enzyme and then never unbinds a suicide inhibitor acts as an irreversible enzyme inhibitor. Suicide inhibition occurs when an enzyme binds the inhibitor (structurally a substrate analogue) and forms an irreversible complex with it, usually through a covalent bond. This can involve the inhibitor being chemically modified by the enzyme during the normal course of catalysis to produce a reactive group that is specifically responsible for the formation of the irreversible inhibitor-enzyme complex.

Question 271

uncompetitive inhibition

Answer 271

inhibitor binds only to enzyme-substrate complex locks substrate in enzyme preventing its release (increasing affinity b/w enzyme and substrate so it lowers Km) Lower Km and vmax Uncompetitive inhibition is when the inhibitor binds to only the enzyme-substrate complex, and inactivates it. This causes the number of active enzyme-substrate complexes to decrease, thereby decreasing Vmax. Km also decreases to exactly the same degree as Vmax. Since both kinetic factors decrease to the same extent, the slope of the Lineweaver-Burk plot of enzyme activity will be the same as for the uninhibited enzyme. The effects of an uncompetitive inhibitor cannot be overcome by increasing substrate concentration. Most commonly, the kinetic parameters Vmax and Km are reported via Michaelis-Menten plots. However, Lineweaver-Burk plots may also be used. When the experimental data are examined in the form of double reciprocal Lineweaver-Burk plots, the x- and y-axes are 1/[S] and 1/V, respectively. Since these plots are a straight line, the slope of each line is Km/Vmax. The y-intercept on a Lineweaver-Burk plot represents 1/Vmax, while the x-intercept is −1/Km. These double-reciprocal plots are especially useful for distinguishing between competitive and noncompetitive inhibitors.

Question 272

non-competitive inhibitor

Answer 272

a molecule that binds to an enzyme at a location outside the active site and inhibits the enzyme’s function. Noncompetitive inhibition is when the inhibitor does not compete with the substrate for the active site, but reduces enzyme activity by binding to another site (the allosteric site) on the enzyme. In noncompetitive inhibition, the inhibitor can combine with either the enzyme or the enzyme-substrate complex. In pure noncompetitive inhibition, the value of Vmax is decreased. Since these inhibitors do not compete with the substrate, their activity is unaffected by substrate concentration. Since the inhibitor always affects a consistent proportion of the available enzyme, Vmax is reduced. However, Km remains the same since if Vmax, is reduced, Vmax/2 is reduced proportionally, and the amount of substrate required to reach this new, reduced Vmax/2 is the same as the original Km.

Question 273

Remember, pKas correspond to ___________, not equivalence points!

Answer 273

half-equivalence points (as shown in pic)

Question 274

hyperventilation results in?

Answer 274

excess CO2 being expelled from the blood, causing the pH to rise. In response, the buffer needs to release more H+ to lower the pH back to physiological norms.

Question 275

Coenzyme Q vs cytochrome C

Answer 275

Unlike coenzyme Q, which carries two electrons, cytochrome c carries only one electron

Question 276

Conversion of pyruvate into glucose requires enzymes present in?

Answer 276

both the mitochondria and the cytosol Conversion of pyruvate to glucose requires its initial conversion into oxaloacetate, in a reaction catalyzed by pyruvate carboxylase in the mitochondria. Oxaloacetate (OAA) is then decarboxylated and phosphorylated by cytosolic or mitochondrial forms of phosophoenolpyruvate carboxykinase (PEPCK). After transport of either OAA in the form of malate or PEP directly from the mitochondria, the remainder of gluconeogenesis takes place in the cytosol.

Question 277

Where does gluconeogenesis occur?

Answer 277

liver and kidney It is upregulated by glucagon and by the presence of surplus pyruvate/acetyl-CoA.

Question 278

How does gluconeogenesis bypass the irreversible/exergonic steps of glycolysis?

Answer 278

gluconeogenesis bypasses these steps using enzymes that catalyze a simple hydrolysis reaction, splitting off a Pi from the carbohydrate

Question 279

what is the difference between kinase, phosphorylase, and phosphatase?

Answer 279

Adds P- kinase and phosphorylase Removes p- phosphatase

Question 280

The formula for a straight-chain alkane is:

Answer 280

CnH2n+2

Question 281

aromatic compound

Answer 281

Aromatic compounds are conjugated cyclic molecules with a planar structure that also satisfy an additional criterion known as Hückel’s rule: having (4n + 2) π-electrons, where n is an integer.

Saturated hydrocarbon formula can be confusing bc its similar CnH2n+2

Question 282

What is the linweaver-burke plot for Competitive inhibition?

Answer 282

Competitive inhibition is when the inhibitor directly competes with the substrate for the active site on the enzyme. This increases Km since it now takes more substrate to ensure half of the active sites are occupied. If enough substrate is supplied, it will outcompete the inhibitor; therefore, Vmax does not change, although more substrate is needed to reach it.

Question 283

What is the linweaver-burke plot for noncompetitive inhibiton?

Answer 283

Noncompetitive inhibition is when the inhibitor does not compete with the substrate for the active site, but reduces enzyme activity by binding to another site (the allosteric site) on the enzyme. In noncompetitive inhibition, the inhibitor can combine with either the enzyme or the enzyme-substrate complex. In pure noncompetitive inhibition, the value of Vmax is decreased. Since these inhibitors do not compete with the substrate, their activity is unaffected by substrate concentration. Since the inhibitor always affects a consistent proportion of the available enzyme, Vmax is reduced. However, Km remains the same since if Vmax, is reduced, Vmax/2 is reduced proportionally, and the amount of substrate required to reach this new, reduced Vmax/2 is the same as the original Km.

Question 284

What is the linweaver-burke plot for uncompetitive inhibition?

Answer 284

Uncompetitive inhibition is when the inhibitor binds to only the enzyme-substrate complex, and inactivates it. This causes the number of active enzyme-substrate complexes to decrease, thereby decreasing Vmax. Km also decreases to exactly the same degree as Vmax. Since both kinetic factors decrease to the same extent, the slope of the Lineweaver-Burk plot of enzyme activity will be the same as for the uninhibited enzyme. The effects of an uncompetitive inhibitor cannot be overcome by increasing substrate concentration. Most commonly, the kinetic parameters Vmax and Km are reported via Michaelis-Menten plots. However, Lineweaver-Burk plots may also be used. When the experimental data are examined in the form of double reciprocal Lineweaver-Burk plots, the x- and y-axes are 1/[S] and 1/V, respectively. Since these plots are a straight line, the slope of each line is Km/Vmax. The y-intercept on a Lineweaver-Burk plot represents 1/Vmax, while the x-intercept is −1/Km. These double-reciprocal plots are especially useful for distinguishing between competitive and noncompetitive inhibitors.

Question 285

Microtubules are used

Answer 285

-in the transport of vesicles and the positioning of organelles within the cell. -microtubules form the spindle apparatus that is an essential part of both mitosis and meiosis. -they are composed of dimers of the protein tubulin

Question 286

Endoplasmic Reticulum

Answer 286

A system of membranes that is found in a cell’s cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids (lipids made in smooth ER).

Question 287

Golgi apparatus

Answer 287

A system of membranes that modifies and packages proteins for export by the cell

Question 288

Peroxisomes

Answer 288

Produce hydrogen peroxide; detoxify harmful substances such as ethanol and break down long fatty acids to medium length fatty acids

Question 289

microfilaments

Answer 289

-composed of two strands of actin polymers -play a role in cell motility -play a role in endocytosis and exocytosis -help with cell cleavage

Question 290

Microtubules

Answer 290

-slightly wider than microfilaments -composed of polymeric dimers of polymers known as alpha-tubulin and beta-tubulin -maintain cell strucutre and make up cilia and flagella -facilitate intracellular transport and make up mitotic spindles

Question 291

intermediate filaments

Answer 291

-structural support and cellular adhesion (ex. keratin)

Question 292

centrioles

Answer 292

-cylindrical structures made up of tubulin and help organize the mitotic spindle -important constituent of the centrosome (microtubule organizing center)

Question 293

prokaryotic flagella vs eukaryotic flagella

Answer 293

powered by ATP in eukaryotes and bacteria powered by a rotary motion powered by a proton gradient

Question 294

G0 phase

Answer 294

resting phase of cell cycle

Question 295

interphase

Answer 295

broken up into G1, S, and G2 cell grows during G1 and G2 and replicates during S

Question 296

G1 checkpoint

Answer 296

restriction point, when a cell commits to division G2 checkpoint checks for DNA damage

Question 297

Prophase

Answer 297

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Question 298

kinetochore

Answer 298

A specialized region on the centromere that links each sister chromatid to the mitotic spindle.

Question 299

telophase

Answer 299

opposite of prophase -new nuclear envelope, nucleolus reappears with nucleus

Question 300

Prokaryotic translation relies on the presence of several release factors.

Answer 300

In contrast, eukaryotes need only one such factor: eukaryotic translation termination factor 1 (eRF1).

Question 301

histones in human nucleosomes:

Answer 301

H1, H2A, H2B, H3, H4,

Question 302

In a negative inducible operon, transcription is inhibited by a

Answer 302

repressor; this results in a basal transcription rate near zero. However, transcription can be “switched on” by the addition of an inducer protein, which blocks the repressor from binding to the operon.

Question 303

Activators bind to DNA sequences and help “recruit” promoters to start transcription.

Answer 303

They are known to upregulate transcription in positive operons, and in the negative lac operon, the cAMP activator protein (CAP) helps promote the transcription of the genes needed for lactose metabolism. However, for CAP to work, the repressor must have also been removed by an inducer (allolactose in the case of the lac operon).

Question 304

Enhancers are

Answer 304

regulatory DNA sequences found only in eukaryotes. In prokaryotes, the operator serves as the regulatory DNA region instead.

Question 305

Oncogenes

Answer 305

are genes that are involved in cell growth and have the potential to cause cancer. Duplication of oncogenes would result in the upregulation of cell growth cell division, potentially leading to uncontrollable mitosis.

Question 306

Cell cycle checkpoint genes are a type of

Answer 306

tumor suppressor gene. They prevent premature cells from undergoing mitosis. For this reason, their amplification would make the cell more resistant to uncontrollable division.

Question 307

Tumor suppressor genes

Answer 307

also known as antioncogenes, regulate cell division. Increased transcription of these genes would reduce the risk of cancer.

Question 308

Inhibitors disable

Answer 308

activators

Question 309

Repressors bind to

Answer 309

operators to reduce transcription

Question 310

Nucleases are enzymes that

Answer 310

cleave nucleic acids. The addition of such enzymes would break down the DNA

Question 311

Proto-oncogene

Answer 311

a gene that regulates normal cell division but that can become a cancer-causing oncogene as a result of mutation or recombination Proto-oncogenes do not necessarily exhibit either a greater or lesser rate of transcription in cancer patients.

Question 312

Acetylation __________ gene expression, while methylation __________ it.

Answer 312

promotes, discourages

Question 313

Methylation of a gene _______ its proclivity to undergo transcription.

Answer 313

lowers

Question 314

Small nucleolar RNAs (or snoRNAs)

Answer 314

are involved in the modification of rRNA. As such, they would be located in the nucleolus, where ribosomes are assembled.

Question 315

snRNA, or small nuclear RNA

Answer 315

is found in the nucleus. These molecules aid in the splicing of pre-mRNA.

Question 316

hnRNA is simply an alternative name for

Answer 316

pre-mRNA. As such, not only is this type of nucleic acid found in the nucleus, it also (at least partially, in its exons) codes for peptide products.

Question 317

tRNA molecules are most likely to be found in the

Answer 317

cytoplasm

Question 318

a test cross

Answer 318

a mating between the unknown individual and an individual known to be homozygous recessive (rrll) for the traits in question

Question 319

Southern Blot

Answer 319

What blotting technique uses the following for analysis? • DNA

Question 320

Northern Blot

Answer 320

Similar technique [to Southern], except that Northern blotting involves radioactive DNA probe binding to sample RNA .

Question 321

Western blot

Answer 321

protein

Question 322

eastern blotting

Answer 322

analyze post-translational modification of peptides

Question 323

wild type

Answer 323

the traits an animal typically possesses when found in nature. This usually refers to a dominant trait, but not always. If nearly all of the coyotes now have spotted fur, then spotted fur is the wild type.

Question 324

In humans, females have two of the same sex chromosome (XX), while males have only one X and one Y. However, the X chromosome is much larger and carries significantly more genes than the Y version. To balance their genetic load with that of males…

Answer 324

one of each female’s X chromosomes is inactivated.

Question 325

Virtually all of the cellular machinery and organelles are maternally inherited. Paternal organelles are destroyed during fertilization.

Answer 325

including the mitochondria, golgi apparatus, and lysosomes

Question 326

Mitochondria divide and segregate to daughter cells…

Answer 326

randomly, so it is possible for some gametes to have more mutated mitochondria than others.

Question 327

At the end of meiosis I, cells are already haploid, though they are still paired with their identical sister chromatids.

Answer 327

For this reason, the 46 chromosomes present in a typical somatic cell have already been reduced to 23 by the time that prophase II is reached.

Question 328

The nuclear membrane temporarily disintegrates in both

Answer 328

prophase II and mitotic prophase.

Question 329

Sister chromatids are pulled apart in

Answer 329

anaphase

Question 330

look up mitosis and meiosis vids

Answer 330

khan academy

Question 331

Genes that are sufficiently close together on a chromosome will tend to

Answer 331

stick together, and the versions (alleles) of those genes that are together on a chromosome will tend to be inherited as a pair more often than not. This phenomenon is called genetic linkage. When genes are linked, genetic crosses involving those genes will lead to ratios of gametes (egg and sperm) and offspring types that are not what we’d predict from Mendel’s law of independent assortment.

Question 332

recombination frequency

Answer 332

So, we can say that a pair of genes with a larger recombination frequency are likely farther apart, while a pair with a smaller recombination frequency are likely closer together. Importantly, recombination frequency “maxes out” at 50\%50%50, percent (which corresponds to genes being unlinked, or assorting independently). That is, 50\%50%50, percent is the largest recombination frequency we’ll ever directly measure between genes.

Question 333

Remember the difference between homologous chromosomes and sister chromatids!

Answer 333

Homologous chromosomes are the pairs of non-identical chromosomes that are present in every somatic cell. (For example, you inherit one version of chromosome 2 from your father and one from your mother; these structures are homologous.) These pairings separate during meiosis I, causing the daughter cells generated by this process to be haploid before the start of meiosis II.

Question 334

In which of these stages do homologous chromosomes separate into distinct cells?

Answer 334

Anaphase of meiosis I

Question 335

synaptonemal complex is a

Answer 335

protein-based linkage that appears during meiosis and connects homologous chromosomes. As these chromosomes must be closely situated to facilitate crossing over, issues could arise involving genetic recombination or synapsis. The synaptonemal complex does not function during mitosis.

Question 336

Genetic drift

Answer 336

is simply the change in allele frequencies due to random processes. Specifically, random chance plays a role in determining which alleles are inherited by offspring from their parents. This can cause some alleles not to be passed down at all, leaving others “fixed” as the only alleles present for that locus. However, genetic drift does not relate to the introduction of new alleles (as mutation does), and cannot increase a population’s genetic diversity.

Question 337

Sympatric speciation

Answer 337

is that which occurs without a physical barrier. A population that diverges into two separate species in a single cave falls under this form of speciation.

Question 338

Parapatric speciation

Answer 338

speciation pattern in which populations speciate while in contact along a common border occurs when segments of two distinct populations overlap. Due to environmental differences, these segments may develop into two species, but individuals in the overlapping areas can typically still interbreed.

Question 339

Allopatric speciation

Answer 339

occurs when populations, or parts of the same population, are separated by a physical barrier. Peripatric speciation is a subtype of this concept that occurs specifically when one of the two populations is much smaller than the other.

Question 340

Convergent evolution

Answer 340

occurs when entirely separate lineages gradually appear more similar over time. Here, bats, birds, and butterflies are very distantly related, but all evolve to possess wings through different mechanisms. In the end, these species resemble each other despite their genetic differences.

Question 341

Parallel evolution

Answer 341

happens when closely related species evolve in a similar way over time. This differs from the question stem, where the three types of organism did not previously resemble each other as strongly.

Question 342

Coevolution

Answer 342

requires that two species evolve in response to each other. The question gives no indication that bats evolved in part “because” birds did so, for example.

Question 343

Divergent evolution

Answer 343

In this phenomenon, two closely related lineages gradually become more dissimilar.

Question 344

Mutualism

Answer 344

is a symbiotic relationship in which both parties benefit. Ex. the ants feed the fungus and the fungus feeds the ants.

Question 345

Commensalism

Answer 345

involves a benefit to only one participating species; the other species is unaffected.

Question 346

Parasitism

Answer 346

occurs when one organism benefits from the relationship at the expense of the other

Question 347

Ectosymbiosis

Answer 347

is a specific phenomenon in which one species lives on the surface of another.

Question 348

cells walls contain

Answer 348

peptidoglycan

Question 349

Gram-negative bacteria

Answer 349

Bacteria that have a thin peptidoglycan cell wall covered by an outer plasma membrane. They stain very lightly (pink) in Gram stain. Gram-negative bacteria are typically more resistant to antibiotics than Gram-positive bacteria.

Question 350

Gram-positive bacteria

Answer 350

Bacteria that have a thick peptido glycan cell wall, and no outer membrane. They stain very darkly (purple) in Gram stain.

Question 351

Bacteria replicate by

Answer 351

binary fission

Question 352

transformation

Answer 352

process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

Question 353

viruses with envelopes are ____ sensitive to outside factors

Answer 353

more

Question 354

Virion

Answer 354

a fully formed virus that is able to establish an infection in a host cell

Question 355

Prion

Answer 355

misfolded proteins that causes other proteins to become misfolded

Question 356

Viriods

Answer 356

infectious particles found in plants that can silence gene expression by binding to specific RNA sequences

Question 357

lytic pathway

Answer 357

Bacteriophage replication pathway in which a virus immediately replicates in its host and then causes it to lyse, releasing progeny phages (so no integration into host genome)

Question 358

lysogenic pathway

Answer 358

Bacteriophage replication path in which viral DNA becomes integrated into the host’s chromosome and then it replicates and lyses releasing progeny phages

Question 359

double membrane bound organelles in eukaryotic cells

Answer 359

mitochondria, ER, Golgi body, and nucleus

Question 360

anterograde vesicles

Answer 360

vessicles leaving ER with newly formed protein cargo, go to golgi after

Question 361

cholesterol in plasma membrane

Answer 361

stabilizes the structure of the plasma membrane when the temperature changes, this reduces fluidity

Question 362

lysosomes

Answer 362

digest proteins (while proteosomes perform functions related to the pentose phosphate pathway and the neutralization of active oxygen species)

Question 363

the inside of the rough ER lumen is similar to…

Answer 363

the extracellular space because proteins are synthesized in the rough ER lumen , and for these proteins to function they must be folded under conditions similar to those in the extracellular environment

Question 364

gap junctions

Answer 364

only allow small molecules through

Question 365

Topoisomerase

Answer 365

Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork.

Question 366

fluid mosaic model

Answer 366

The mentioned model involves two main aspects: “fluid” and “mosaic.” The “fluid” aspect refers to the ability of component molecules to travel laterally within their leaflet of the bilayer, while the word “mosaic” denotes the presence of proteins and other molecules that are scattered in a mosaic within its structure.

Question 367

fluidity of a membrane

Answer 367

We are looking for characteristics of a membrane that increase fluidity, especially in cold environments. Unsaturated fatty acids increase fluidity in general, due to the presence of “kinks” in their structure. Cholesterol and similar molecules, which act as a type of buffer system for membrane fluidity, are slightly more complex. Large amounts of cholesterol decrease fluidity at high temperatures but increase it at low temperatures.

Question 368

sodium potassium pump, how many in/out

Answer 368

The Na+/K+ pump helps the cell maintain its membrane potential and creates a concentration gradient. It does this by moving sodium out of the cell and transporting potassium inward. It pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell.

Question 369

the Na+/Ca2+ exchanger must

Answer 369

move calcium ions out of the cell.

Question 370

After a molecule has been engulfed via endocytosis, in what order does it progress through membrane-bound compartments before it is degraded?

Answer 370

Early endosome, late endosome, lysosome

Question 371

Goldi apparatus

Answer 371

The Golgi apparatus functions like a cellular “post office.” It receives proteins from the endoplasmic reticulum and packages them into vesicles; these membrane-bound sacs can then travel to specific locations within the cell or to the plasma membrane for excretion. Additionally, lysosomes are formed from vesicles that bud off the Golgi’s larger structure. However, note that choice D references enzyme production. Since nearly all enzymes are protein-based, it is the ribosomes - whether free-floating or attached to the rough ER - that synthesize them.

Question 372

Rough ER

Answer 372

synthesis of transmembrane proteins

Question 373

Nucleolus

Answer 373

rRNA production and ribosome assembly

Question 374

lysosomes

Answer 374

facilitate the enzymatic catabolism of protein

Question 375

Peroxisomes

Answer 375

are small membrane-bound organelles that function mainly to break down lipids

Question 376

removal of the ER

Answer 376

Removal of the ER might disrupt the outer leaflet of the nuclear envelope, potentially releasing the contents of the nucleus into the cell and triggering apoptosis.

Question 377

Macrophages must undergo ____ during phagocytosis. If a macrophage cannot engulf bacteria in this

Answer 377

rapid actin reorganization If a macrophage cannot engulf bacteria in this manner, its overall function would be considered very impaired.

Question 378

collagen

Answer 378

is not a cytoskeletal polymer; it is an extracellular fiber that is secreted by certain cell types.

Question 379

Microtubule linking proteins

Answer 379

as their name implies, are used to bind bundles of microtubules together. This is most notably observed in eukaryotic flagella. If these proteins cannot be synthesized, flagella will not work properly, and the function of cells that rely on these structures will be diminished. Of the listed cells, only spermatozoa (sperm cells) possess flagella.

Question 380

Keratin fibers extend across epithelial cells (in the skin, for example) to link adjacent cells via structures called desmosomes.

Answer 380

As a type of intermediate filament, keratin possesses high tensile strength; as such, it can form a network of fibers that distribute mechanical stress among the cells of an epithelial layer. Keratin is therefore the cytoskeletal protein that contributes most to the skin’s stretching ability.

Question 381

Collagen contributes heavily to the tensile strength of connective tissue in the skin.

Answer 381

However, it is a fiber in the extracellular matrix, not a component of the cytoskeleton.

Question 382

As some of the longest cells in the body, neurons rely on___to transport neurotransmitter-containing vesicles and macromolecules along their axons.

Answer 382

Type c polymers Therefore, one can expect to find the longest type C polymers in neural cells like those in the cerebral cortex.

Question 383

Cytokinesis involves

Answer 383

a contracting ring of actin microfilaments that pinches the two daughter cells apart. Preventing actin monomers from polymerizing will inhibit the filament reorganization necessary for cytokinesis to occur.

Question 384

Centrosome polarization involves

Answer 384

microtubules Specifically, microtubule extension pushes the centrioles to opposite sides of the cell during mitosis.

Question 385

The formation of the mitotic spindle involves

Answer 385

microtubules, which organize themselves around the centriole.

Question 386

Gram-negative bacteria have

Answer 386

a thinner cell wall, which allows the crystal violet stain to exit the cell. Gram staining first involves exposure to crystal violet stain, which is then fixed with iodine. Gram-positive organisms possess a thick peptidoglycan wall which attaches to crystal violet particles, preventing them from leaving the cell when it is subsequently washed. As a result, these cells stain purple. Gram-negative bacteria, in contrast, possess a thin cell wall that does not fix to the crystal violet stain. Instead, these cells are later stained pink with a counterstain.

Question 387

Gram-positive

Answer 387

thick cell wall - outer membrane absent

Question 388

Which organisms are dependent on the electron transport chain to create ATP?

Answer 388

All obligate aerobes

Question 389

One characteristic of prokaryotic, but not eukaryotic, transcription is that:

Answer 389

mRNA does not undergo post-transcriptional modification.

Question 390

Transduction

Answer 390

a bacteriophage transfers genetic material from one bacterial cell to another during infection.

Question 391

Transformation

Answer 391

occurs when bacteria pick up genetic material from their surroundings.

Question 392

F, or fertility, factor

Answer 392

is a piece of genetic material that codes for the construction of a sex pilus. This bridge allows a bacterium to transfer the factor to another cell, promoting genetic diversity. However, only bacteria with the factor can initiate this transfer, and only to cells that lack it. Typically, the F factor is held outside the main genome in the form of a small plasmid. However, Hfr bacteria represent an interesting phenomenon; in these cells, the F plasmid has become incorporated into the organism’s circular chromosome. As these cells do contain the F factor, they can initiate conjugation to F- cells, but they often transfer genomic material along with part or all of the factor.

Question 393

Class I transposons

Answer 393

are known as “copy-and-paste” transposons, as they involve the creation of a new copy of the transposable element. These elements first undergo transcription into RNA using RNA polymerase; as their name implies, they are then reverse transcribed back into DNA and placed in a distinct location elsewhere in the genome.

Question 394

(-)RNA

Answer 394

Negative-sense RNA

Question 395

Prions

Answer 395

tend to induce misfolding and aggregation of endogenous cellular proteins, forming highly stable amyloid fibers. The natural cellular response to the presence of misfolded proteins is the production of heat shock proteins, which help to properly fold the defective protein molecules. The absence of heat shock activity suggests that the cell is not experiencing any problems with protein aggregation, which is one of the hallmarks of prion disease pathology.

Question 396

initiatior tRNA is bound to ____ in eukaryotes and _____ in prokaryotes

Answer 396

methionine-eukaryotes and N-formylmethionine-prokaryotes

Question 397

Conditions of Hardy-Weinberg Equilibrium

Answer 397

1. No mutations 2. Random mating 3. No natural selection 4. Extremely large population size 5. No gene flow 6. no migration in or out of the population

Question 398

Hardy-Weinberg equilibrium equation

Answer 398

p^2 + 2pq + q^2 = 1 p+q=1 p= frequency of dominant allele

Question 399

incomplete penetrance

Answer 399

Clinical symptoms are not always present in individuals who have the disease-causing mutation

Question 400

Expresivity

Answer 400

variations in a phenotype among individuals carrying a particular genotype

Question 401

ANOVA test

Answer 401

-Test of statistical significance when >2 groups.

Question 402

genetic linkage

Answer 402

tendency for genes located close together on the same chromosome to be inherited together, and ones father apart are less likely, but not proportionately so, happens bc crossing over

Question 403

bacteria are

Answer 403

haploid organisms

Question 404

negative control

Answer 404

a repressor prevents transcription by binding to operator ( a sequence upstream of the first protein-coding region) both lac operon and trp operon function based on negative control

Question 405

positive control

Answer 405

an activator stimulates transcription

Question 406

negative inducible operon

Answer 406

the repressor is normally present and the genes are not expressed except under certain conditions

Question 407

negative repressible operon

Answer 407

the genes are usually transcribed,but transcription can be halted by binding of the repressor in appropriate conditions

Question 408

lac operon

Answer 408

-produces genes that use lactose for energy -when high lactose, allolactose get formed from lactose (an isomer) and binds to the repressor, detaching it -if glucose levels low, then cAMP active and binds to CAP which binds to CAP binding sequence and promotes transcription -lac operon is under positive and negative control

Question 409

trp operon

Answer 409

-repressible operon -produces genes necessary to synthesize tryptophan -when tryptophan is absent the repressor does not bind to the operator, and tryptophan synthesis proceeds -when tryptophan is present it binds to the repressor protein and causes it to bind to the operator, thereby inhibiting synthesis -transcription is not repressed by default, but can be induced by environmental conditions, thus is considered a repressible negative operon -

Question 410

endonuclease v exonuclease

Answer 410

Endo-nuclease directly cuts the polynucleotide chain results into two or more fragments whereas exonuclease cuts the nucleotide bases one by one from 3’ or 5’ end. Endo-nuclease creates single-stranded nick within a chain whereas exonuclease removes the single nucleotides from the end.

Question 411

dideoxy nucleotides are missing which -OH?

Answer 411

3’

Question 412

S phase is

Answer 412

not part of mitosis

Question 413

G2-M checkpoint checks?

Answer 413

that the recently-replicated DNA was copied accurately; if not, mitosis will not occur.

Question 414

Cyclin and Cdks are

Answer 414

crucial cell cycle regulators

Question 415

2 checkpoint in cell cycle

Answer 415

The G1 phase is responsible for protein and organelle production in addition to cell growth. Two major checkpoints mark the cell cycle: one during G1 and the other in G2. In order to pass the G1 checkpoint, the cell must have reached a sufficient size and synthesized enough organelles to move into the S phase. The checkpoint between G2 and mitosis ensures that DNA replication has proceeded accurately.

Question 416

Ectoderm

Answer 416

outermost germ layer; produces sense organs, nerves, and outer layer of skin

Question 417

Endoderm

Answer 417

the inner germ layer that develops into the lining of the digestive and respiratory systems

Question 418

Mesoderm

Answer 418

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

Question 419

in deuterosomes the blastopore becomes the

Answer 419

anus

Question 420

morula

Answer 420

a spherical collection of sixteen cells that is the same size as the original zygote. Further division results in the blastula, a hollow ball of cells. The blastula then develops into the gastrula, which is an invaginated structure containing three germ layers.

Question 421

fibroblasts

Answer 421

cells that produce the fibers comprising connective tissues such as collagen

Question 422

Fibronectin

Answer 422

glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins

Question 423

Cloudin and occludin

Answer 423

proteins that form tight junctions between epithelial cells

Question 424

sympathetic nervous system

Answer 424

stimulates the heart rate and excites the body into activity

Question 425

parasympathetic nervous system

Answer 425

rest and digest, calms you down

Question 426

positioning of neurons in spinal cord

Answer 426

Sensory, or afferent, tracts lie toward the rear (dorsal) side of the spinal cord. In contrast, motor, or efferent, tracts are positioned near the front (ventral) and lateral sides.

Question 427

Depolarization refers to

Answer 427

any phase in which the cell becomes more positive (or less polarized) than its resting value) resting membrane potential for a typical neuron is -70 mV

Question 428

During most of the duration of an action potential, another stimulus, regardless of its strength, cannot cause the neuron to fire again. This is termed the absolute refractory period, and it can be attributed to:

Answer 428

the fact that sodium channels are inactivated.

Question 429

EPSP

Answer 429

Excitatory postsynaptic potential; a slight depolarization of a postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for an action potential.

Question 430

IPSP

Answer 430

Inhibitory postsynaptic potential; a slight hyperpolarization of the postysynaptic cell, moving the membrane potential of that cell further from threshold.

Question 431

inhibitory neurotransmitters

Answer 431

hyperpolarizes (makes more negative) which takes it further from the threshold needed to execute an action potential

Question 432

The adrenal gland can be subdivided into two parts, the adrenal cortex and adrenal medulla, they each produce:

Answer 432

-cortex produces aldosterone and cortisol -medulla secretes epinephrine and norepinephrine.

Question 433

anterior pituitary produces

Answer 433

FSH, LH, ACTH, TSH, prolactin, and growth hormone (GH)

Question 434

the ___________ pituitary does not produce the hormones it secretes

Answer 434

posterior

Question 435

parathyroid glands produce and secrete parathyroid hormone (PTH), which opposes

Answer 435

calcitonin to regulate calcium levels. PTH increases plasma calcium by increasing Ca2+ absorption in the small intestine and extraction of the ion from bone. In other words, high PTH results in high plasma calcium and low bone density. Thus, we can expect that lowered PTH levels would decrease blood calcium levels.

Question 436

the adrenal medulla releases

Answer 436

epinephrine and norepinephrine

Question 437

The adrenal cortex synthesizes and releases

Answer 437

aldosterone and cortisol

Question 438

Oncotic (osmotic) pressure

Answer 438

a force that attempts to pull fluid from the interstitial and intracellular spaces into the capillary, other vessels (arteries etc) are too thick for this to happen

Question 439

myocyte

Answer 439

muscle cell

Question 440

cardiac muscle v smooth muscle

Answer 440

The tissue of the heart itself is composed of cardiac muscle, but blood vessels are coated in smooth muscle

Question 441

speed of blood flowing through capillaries v through other types of blood vessels

Answer 441

The continuity equation is often written as A1v1 = A2v2. This shows us that fluids travel slower through vessels with larger areas. However, we cannot compare the area of a single capillary to that of a single artery or vein, since one artery branches off into many arterioles, which then each branch to form countless capillaries. Thus, it is the combined area of all capillaries - a huge value - that helps us realize that capillaries experience the slowest blood flow of all circulatory vessels. Alternatively, we could simply remember that blood must travel slowly through capillaries to maximize gas and nutrient exchange.

Question 442

Albumin

Answer 442

protein in blood; maintains the proper amount of water in the blood, is the heaviest layer when blood is centrifuged

Question 443

myoglobin v hemoglobin

Answer 443

Myoglobin is found in the muscle, while hemoglobin is found only in the blood. Both molecules use a heme cofactor with an iron center. Myoglobin has a higher oxygen affinity, allowing it to draw oxygen out of the blood effectively. Myoglobin has only one oxygen-binding site. Consequently, it does not bind oxygen cooperatively. Hemoglobin, in contrast, utilizes cooperative binding.

Question 444

2,3-BPG

Answer 444

binds hemoglobin and causes a decrease in oxygen affinity. In adults, this aids in oxygen delivery to the peripheral tissues. Fetal insensitivity to 2,3-BPG permits heightened saturation of fetal hemoglobin. The plasma concentration of 2,3-BPG increases at high altitudes to enables more oxygen to be delivered to the tissues. In other words, 2,3-BPG actually assists oxygen delivery

Question 445

Hemoglobin Binding Curve

Answer 445

4 subunits present in hemoglobin that can be either T or R -state. Cooperative binding leads to a sigmoidal curve.

Question 446

Carbonic anhydrase catalyzes the conversion of water and carbon dioxide to carbonic acid. This process is a crucial part of the maintenance of a buffered blood pH. Which metal cofactor is necessary for carbonic anhydrase to function?

Answer 446

Zinc

Question 447

Hemoglobin’s oxygen binding affinity is affected by the pH of its environment and the concentration of carbon dioxide. This relationship is described as the Bohr effect. Which of these conditions would increase the affinity between hemoglobin and oxygen?

Answer 447

The Bohr effect characterizes the inverse relationship between binding affinity and plasma carbon dioxide concentration. An increase in [CO2] generally correlates to an oxygen deficiency, as when an individual exercises. In such conditions, hemoglobin must be able to release oxygen when it reaches the tissues. As a result, when the concentration of carbon dioxide increases, hemoglobin decreases its affinity for oxygen. In contrast, low CO2 concentrations facilitate an increase in binding affinity. Since CO2 in the plasma directly leads to the formation of carbonic acid, low [CO2] correlates to alkaline, or basic, blood.

Question 448

Neutrophils

Answer 448

A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease.

Question 449

basophils

Answer 449

A circulating leukocyte that produces histamine.

Question 450

Helper T cells

Answer 450

Helper T cells are critical for activation of the humoral immune response (B cells) and the cellular immune response (T cells). Helper T cells also produce cytokines that fully activate macrophages, allowing them to establish a more acidic phagosomal pH and kill pathogens more effectively.

Question 451

The major histocompatibility complex (MHC)

Answer 451

a set of genes that code for cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates, which in turn determines histocompatibility

Question 452

dendritic cells

Answer 452

specialized white blood cells that patrol the body searching for antigens that produce infections Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems.

Question 453

innate immunity

Answer 453

Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.

Question 454

adaptive immunity

Answer 454

the ability to recognize and remember specific antigens and mount an attack on them

Question 455

Nernst equation

Answer 455

Ecell= (RT/nF) (lnQ) used to calculate equilibrium potential, used with neurons

Question 456

hypothalamus vs thalamus

Answer 456

hypothalamus- links the nervous system to the endocrine system via the pituitary gland thalamus-relays sense and motor signals, regulates sleep and alertness

Question 457

1, 6 branching bonds in glycogen are broken by

Answer 457

glycogen debranching enzyme

Question 458

1,4 straight chains of glycogen are broken by

Answer 458

glycogen phosphorylase

Question 459

rate limiting and committed step of glycolysis

Answer 459

Phosphofructokinase-1

Question 460

_______ transports glucose into the cell and is inhibited by high levels of _______

Answer 460

hexokinase, its own produce-G6P

Question 461

Glucokinase

Answer 461

present in the pancreatic beta cells as part of the glucose sensor and is responsive to insulin in the liver, its activity is positively correlated with blood sugar

Question 462

at the peak of action potential

Answer 462

sodium ions are not flowing potassium is flowing out

Question 463

electrical synapses, which operate through gap junctions, are composed of which protein subunit

Answer 463

connexin

Question 464

efferent nerves

Answer 464

motor nerves responsible for reflexes

Question 465

viruses are not

Answer 465

diploid

Question 466

Goal of PCR

Answer 466

make many copies of a DNA sequence

Question 467

genetic bottleneck

Answer 467

temporary dramatic reduction in size of a population or species

Question 468

penetrance vs. expressivity

Answer 468

penetrance- probability of gene being expressed if present, it’s either expressed or not expressivity- how much genotype is expressed as phenotype, incomplete dominance, the extent to which penetrance happens

Question 469

peptide hormones are associated with

Answer 469

rapid, short term changes in physiological function

Question 470

Are steroid hormones soluble in the blood stream?

Answer 470

no they require transport hormones to reach their targets (ex. sex-hormone-binding globulin, albumin) -once in the cell they bind with nuclear receptors, the nuclear receptor-hormone complex undergoes conformational change and is translocated to the nucleus where the complex binds to DNA and affects gene transcription

Question 471

peptide v steroid hormones

Answer 471

Peptide: -amino acids are the biochemical precursor -usually large -polar -synthesis: Rough ER->Golgi->vesicles->exocytosis -has intermediate stages (preprohormones, prohormones, hormones) -soluble in blood -membrane-bound receptor -uses secondary messenger signal cascade -fast-onset, short-term -functions as a short term response and as a regulator of other hormones -ex: TSH, oxytocin, insulin, calcitonin Steroid: -cholesterol is the biochemical precursor -small -nonpolar -made in smooth ER -no intermediate stages -insoluble in blood, require a transport protein -uses a nuclear receptor -diffuses through membranes -effects DNA transcription in nucleus -slow onset with longer term effects -regulate 3 S’s: Salt, Sugar, and Sex ex. estrogen, testosterone, cortisol, aldosterone

Question 472

Tropic Hormones of Anterior Pituitary

Answer 472

TSH, FSH, LH, ACTH affect the release of other hormones

Question 473

Aldosterone

Answer 473

-“salt-retaining hormone” which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure -also secretes potassium -adrenal cortex

Question 474

Atrial natriuretic peptide (ANP)

Answer 474

oppostie of aldosterone, is released in response to high blood volume and decreases sodium reabsorption

Question 475

Tyrosine Hormones

Answer 475

All derived from the amino acid tyrosine: can act either like steroid or protein hormones so are their own class dopamine catecholamines (act like proteins): norepinephrine, epinephrine, thyroid hormones (act like steroid hormones): T3, T4

Question 476

Hormones that regulate blood glucose

Answer 476

-insulin-lowers glucose levels -glucagon-increases glucose levels -cortisol-increases glucose levels -epinephrine- increases glucose levels -growth hormone-increases glucose levels

Question 477

hormones that regulate calcium levels

Answer 477

-parathyroid hormone (PTH)-increases calcium levels -calcitonin-decreases calcium levels

Question 478

hormones that have to do with fluid regulation

Answer 478

-aldosterone-increases Na+ reabsorption in DCT, increases fluid levels -ADH/vasopressin (same thing)-increases H2O absorption in collecting duct -Atrial natriuric peptide (ANP)-decreases Na+ reabsorption in DCT, decreases fluid levels

Question 479

hormones having to do with stress

Answer 479

-cortisol-increases glucose, decreases inflammation -epinephrine and norepinephrine-increases glucose, regulates sympathetic nervous system and the fight or flight response

Question 480

hormones that regulate metabolic rate

Answer 480

T3 and T4-increase the basal metabolic rate

Question 481

hormones that regulate reproduction and development

Answer 481

-estrogen-female secondary sex characteristics, menstrual cycle regulation -testosterone-male secondary sex characteristics -progesterone-prepares and maintains uterus for pregnancy -LH-increases estrogen or testosterone -FSH-follicle development, spermatogenesis -hCG-increases progesterone levels -prolactin-milk production -oxytocin-smooth muscle contraction (uterine contractions in labor, milk release in breastfeeding)

Question 482

tropic hormones

Answer 482

-TSH-increases thyroid hormones -adrenocorticotropic hormone (ACTH)-increases adrenal cortex activity and thus corticosteroids -LH-increases estrogen and testosterone levels -FSH-follicle development, spermatogenesis -hCG-increases progesterone levels -GnRH-increases LH and FSH levels -Thyrotropin-releasing hormone (TRH)-increases TSH -Corticotropin-releasing factor (CRF)-increases ACTH levels -Growth hormone-releasing hormone (GHRH)-increases growth hormone levels

Question 483

Hypothalamus hormones

Answer 483

GnRH, GHRH, TRH, CRF, PIF

Question 484

anterior pituitary hormones

Answer 484

FSH, LH, TSH, STH, ACTH, GH, and prolactin Anterior Pituitary Hormones”FLAGTOP” F: Follicle Stimulating Hormone L: Luteinizing Hormone A: ACTH G: Growth Hormone T: Thyroid Stimulating Hormone O: MSH - melanOcyte stimulating hormone P: Prolactin

Question 485

posterior pituitary hormones

Answer 485

ADH (vasopressin) and oxytocin

Question 486

only parathyroid hormone is: parathyroid hormone

Answer 486

A hormone of the parathyroid gland that regulates the metabolism of calcium and phosphorus in the body.

Question 487

thyroid hormones

Answer 487

T3, T4, calcitonin

Question 488

adrenal cortex hormones

Answer 488

aldosterone and cortisol

Question 489

adrenal medulla hormones

Answer 489

catecholamines (epinephrine and norepinephrine)

Question 490

Pancreas hormones

Answer 490

insulin, glucagon, somatostatin (inhibits digestive hormones, slows digestion)

Question 491

reproductive organ hormones

Answer 491

estrogen, testosterone, progesterone, human chorionic gonadotropin (hCG)-Human chorionic gonadotropin (hCG) is a hormone produced by the placenta after implantation.

Question 492

keratin is

Answer 492

an intermediate filament

Question 493

actin and ______ are the same thing

Answer 493

microfilaments

Question 494

negatively charged forms of asparagine and glutamine

Answer 494

asparatate and glutamate

Question 495

a mother’s breastmilk transfers this immune protection to the infant:

Answer 495

igG antibodies

Question 496

Gastrulation

Answer 496

the process in which a gastrula develops from a blastula by the inward migration of cells aka the process whereby the inner cell mass is converted into the trilaminar embryonic disk comprised of the three primary germ layers (ectoderm, mesoderm, and endoderm)

Question 497

Ectoderm

Answer 497

outermost germ layer; produces sense organs, nerves, and outer layer of skin

Question 498

Endoderm

Answer 498

innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system

Question 499

Mesoderm

Answer 499

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

Question 500

the normal maturation pathway of ova is…

Answer 500

oogonia (2n)->Primary oocyte (occurs via mitosis, 2n) ->secondary oocyte (completion of meiosis 1, n) -> mature ovum (completion of meiosis 2, this process requires sperm (n)) each month one primary oocyte comes out of its arrest (in prophase 1) and develops into a secondary oocyte, which ruptures from the follicle and is released into the fallopian tube