Biochemistry

Question 1

Actin

Answer 1

makes up microfilaments and the thin filaments in myofibrils, the most abundant protein in eukaryotic cells

Question 2

Myosin

Answer 2

the primary motor protein that interacts w/ actin, roles include the thick filament in a myofibril and it is involved in cellular transport

Question 3

Kinesins

Answer 3

motor protein assoc. w/ microtubules, roles in aligning chromosomes during metaphase and depolymerizing microtubules during anaphase of mitosis

Question 4

Dyneins

Answer 4

motor protein assoc. w/ microtubules, involved in sliding movement of cilia and flagella

Question 5

Native PAGE

Answer 5

useful to compare the molecular size or the charge of proteins known to be similar in size from other analytical methods like SDS-PAGE or size exclusion chromatography

Question 6

Electrophoresis

Answer 6

subjects compounds to an electric field which moves them according to their net charge and size (neg. charged compounds migrate toward pos. charged anode & pos. charged compounds migrate toward neg. charged cathode), —small & charged molecules migrate faster than bigger electrically neutral molecules

Question 7

SDS-PAGE

Answer 7

separates proteins on the basis of relative molecular mass alone

Question 8

Isoelectric Focusing

Answer 8

exploits the acidic and basic properties of AAs by separating on the basis of isoelectric point (pI)

Question 9

Chromatography

Answer 9

a variety of techniques that require the homogenized protein mixture to be fractionated through a porous matrix, preferred over electrophoresis when large amounts of protein are being separated

Question 10

Size Exclusion Chromatography

Answer 10

the small compounds are slowed down and retained longer

Question 11

The number of poss. stereoisomers of a compound can be calculated by

Answer 11

2^n

Question 12

D-sugars

Answer 12

all have the hydroxide of their highest numbered chiral center on the right

Question 13

L-sugars

Answer 13

all have the hydroxide of their highest numbered chiral center on the left

Question 14

Epimers

Answer 14

special subtype of diastereomers that differ in configuration at exactly one chiral center

Question 15

Tautomerization

Answer 15

the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond

Question 16

Enol

Answer 16

a compound w/ a double bond and an alcohol group

Question 17

Saturated fatty acids

Answer 17

contain only single bonds , form solids at room temperature

Question 18

Unsaturated fatty acids

Answer 18

includes one or more double bonds, tend to be liquids at room temperature

Question 19

Fat-soluble vitamins

Answer 19

A (carotene) (vision, growth, development, immune function)
D (cholecalciferol) (increases calcium and phosphate uptake in the intestines, which promotes bone production)
E (biological antioxidants, prevents oxidative damage)
K (vital to post translational modification required to form prothrombin, an important clotting factor in the blood, introduce calcium-binding sites on several calcium-dependent proteins)

Question 20

Saponification

Answer 20

is the ester hydrolysis of triaglycerols using a strong base (base traditionally used is lye)
-result is the basic cleavage of the fatty acid leaving the sodium salt of the fatty acid (what we know as soap) and glycerol

Question 21

Purines

Answer 21

contain two rings in their structure; adenine (A) and guanine (G)

Question 22

Pyrimidines

Answer 22

contain only one ring in their structure; cytosine (C), thymine (T), and uracil (U)

Question 23

Complementary base pairing

Answer 23

an adenine (A) is always base-paired with a thymine (T) via two hydrogen bonds; a guanine (G) always base-pairs with a cytosine (C) via three hydrogen bonds

Question 24

Chargaff’s Rules

Answer 24

the amount of A equals the amount of T and the amount of G equals the amount of C

Question 25

DNA polymerase reads 3' to 5', but the following processes occur 5' to 3'

Answer 25

-DNA synthesis -DNA repair -RNA transcription -RNA translation

Question 26

messenger RNA (mRNA)

Answer 26

carries the information specifying an amino acid sequence of the protein to the ribosome

Question 27

transfer RNA (tRNA)

Answer 27

responsible for converting the language of nucleic acids to the language of amino acids and peptides

Question 28

ribosomal RNA (rRNA)

Answer 28

synthesized in the nucleolus and functions as an integral part of the ribosomal machinery used during protein assembly in the cytoplasm

Question 29

start codon

Answer 29

methionine (AUG)

Question 30

stop codon

Answer 30

UGA, UAG, UAA

Question 31

Passive transport

Answer 31

used by spontaneous processes that do not require energy (negative ΔG) -utilize the concentration gradient to supply the energy for particles to move ex: simple diffusion, osmosis, facilitated diffusion

Question 32

Active transport

Answer 32

used by non spontaneous processes that require energy (positive ΔG), results in the net movement of a solute against its concentration gradient

Question 33

Na+/K+ ATPase

Answer 33

maintains a low concentration of sodium ions and high concentration of potassium ions intracellularly by pumping three sodium ions out for every two potassium ions pumped in

Question 34

Fermentation

Answer 34

occurs in the absence of oxygen -in yeast cells, it is the conversion of pyruvate (three carbons) to ethanol (two carbons) and carbon dioxide (one carbon) -replinish NAD+

Question 35

Irreversible steps of glycolysis

Answer 35

Hexokinase Glucokinase PFK-1 Pyruvate Kinase

Question 36

Glycogenesis

Answer 36

the synthesis of glycogen granules -begins w/ glycogenic

Question 37

Glycogenolysis

Answer 37

the breakdown of glycogen using two main enzymes: glycogen phosphorylase and debranching enzyme

Question 38

Gluconeogenesis

Answer 38

occurs in both the cytoplasm and mitochondria, predominantly in the liver -most of it is simply the reverse of glycolysis, using the same enzymes -the 3 irreversible steps of glycolysis must be bypassed by different enzymes: Pyruvate carboxylase, Fructose 1,6 biphosphatase, glucose 6 phosphatase

Question 39

Pentose Phosphate Pathway

Answer 39

occurs in the cytoplasm of all cells, functions: production of NADPH and serving as a source of ribose 5-phosphate for nucleotide synthesis

Question 40

Krebs cycle

Answer 40

-occurs in the mitochondria (mitochondrial matrix) -main function: the oxidation of acetyl-CoA to CO2 and H2O, also produces high energy electron-carrying molecules NADH and FADH2 -although oxygen is not directly required in the cycle, the pathway will not occur anaerobically -isocitrate dehydrogenase is the rate-limiting enzyme of this cycle -high levels of ATP and NADH inhibit this cycle, while high levels of ADP and NAD+ promote it

Question 41

Electron transport chain

Answer 41

-complex 1: NADH + H+ + CoQ = NAD+ + CoQH2] (4 protons moved to intermembrane space) -complex 2: succinate + CoQ + SH+ = fumarate + CoQH2 (no hydrogen pumping occurs here to contribute to the proton gradient) -complex 3: CoQH2 + 2 cytochrome c [with Fe3+] = CoQ + 2 cytochrome c [with Fe2+] + 2H (four protons are diplaced to the intermembrane space) -complex 4: 4 cytochrome c [with Fe2+] + 4 H+ + O2 = 4 cytochrome c [with Fe3+] + 2 H2O (two protons are moved across the membrane)

Question 42

Internal energy

Answer 42

the sum of all of the different interactions between and within atoms in a system; vibration, rotation, linear motion, and stored chemical energy -bc the system is closed, the change in internal energy can only come in the form of work or heat, represented by the first law of thermodynamics, (ΔU = Q - W)

Question 43

Enthalpy

Answer 43

measures the overall change in heat of a system during a reaction -at constant pressure and volume, enthalpy and thermodynamic heat heat exchange (Q) are equal

Question 44

Entropy

Answer 44

measures the degree of disorder or energy dispersion in a system -carries the units J/K

Question 45

Gibbs Free Energy equation

Answer 45

ΔG = ΔH -TΔS -predicts the direction in which a chemical rxn proceeds spontaneously -spontaneous: forward direction, negative ΔG -nonspontaneous: spontaneous in the reverse direction, positive ΔG

Question 46

ATP forms

Answer 46

-ATP consists of an adenosine molecule attached to 3 phosphate groups and is consumed either through hydrolysis or the transfer of a phosphate group to another molecule -if one phosphate group is removed, ADP is produced -if two phosphate groups are removed, AMP is produced --continuous recycling of ATP, ADP, and Pi more than 1000 times per day accounts for this discrepancy

Question 47

Anabolism

Answer 47

synthesis of biomolecules

Question 48

Catabolism

Answer 48

breakdown of biomolecules for energy

Question 49

counter regulatory hormones

Answer 49

glucagon, cortisol, epinephrine, norepinephrine, and growth hormone -oppose the actions of insulin, their effect on skeletal muscle, adipose tissue, and the liver are opposite to the actions of insulin

Question 50

Thyroid hormones

Answer 50

increase basal metabolic rate -T4: occurs after a latency of several hours but may last for several days -T3: produces a more rapid increase in metabolic rate and has a shorter duration of activity

Question 51

Respiratory quotient

Answer 51

RQ = CO2 produced/ O2 produced - carbohydrates: 1.0 - lipids: 0.7 - resting individuals: 0.8