UWorld

Question 1

phosphate groups are most often added to which functional group?

Answer 1

hydroxyl group (-OH)

Question 2

where does phosphorylation most typically occur?

Answer 2

on hydroxyl groups (-OH)

Question 3

which amino acids are most easily phosphorylated?

Answer 3

those with hydroxyl groups
(serine, threonine, tyrosine)

Question 4

allosteric effectors

Answer 4

bind to proteins at one site and cause a conformational change at another site

Question 5

SDS PAGE

Answer 5

separates proteins by size (molecular weight)

smaller fragments travel faster / further

Question 6

proteases

Answer 6

degrade proteins into smaller fragments

by hydrolyzing peptide bonds

Question 7

what does Kd stand for

Answer 7

dissociation constant

Question 8

small Kd value = ….

Answer 8

high binding affinity

low tendency for the complex to dissociate

Question 9

what is the bond that connects amino acids in a protein

Answer 9

peptide bonds

Question 10

thermodynamic stability of a bond…

Answer 10

refers to its tendency to form or break in chemical reactions

Question 11

a thermodynamically stable bond…

Answer 11

a bond that forms during a spontaneous reaction

Question 12

a thermodynamically unsdtable bond forms during a – reaction

Answer 12

forms during a** nonspontaneous** reaction

Question 13

```

~~~

non-spontaneous reactions

Answer 13

require energy input in order to proceed4

Question 14

ATP hydrolysis

Answer 14

the breakdown of ATP to ADP + Pi via the addition of water

Question 16

thermodynamically stable reaction

Answer 16

spontaneous; proceed without the addition of energy

do not necessarily proceed quickly

Question 17

what classs of macromolecule are antibodies?

Answer 17

proteins

Question 18

kinetically stable bonds…

Answer 18

the breakdown of their bonds have slow reaction rates (high activation energy)

Question 19

antibodies bind via …

Answer 19

noncovalent interactions

Question 20

precision

Answer 20

when similar results are obtained from trial to trial

whether or not they are accurate

Question 21

accuracy

Answer 21

accuracy describes how close results reflect and represent a real-world value, assessed by comparison to a “gold standard”

Question 22

validity

Answer 22

a study is valid if it results are both precise and accurate

Question 23

what does Kcat represent?

Answer 23

the turnover number: the number of subsrate molecules converted to product pr enzyme per unit of time when the enzyme is saturated with product

Question 24

enzyme equation: Vmax = …

Answer 24

Question 25

gibbs free energy vs gibbs standard free energy

equation

Answer 25

Question 26

true or false: a reaction may be non spontaneous under but spontaneous in vivo

Answer 26

TRUE

Question 27

what is Gibb’s standard free energy

Answer 27

this is just the free energy of a reaction under standard conditions

Question 28

le chateliers principle states that…

Answer 28

if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change and reestablish an equilibrium

Question 29

state function

definition

Answer 29

a property whose value does not depend on the path taken to reach that specific value

Question 30

example of state functions

Answer 30

temperature, pressure, density, volume, Gibb’s energy free, enthalpy, internal energy, and entropy

Question 31

path functions

definition and examples

Answer 31

depend on the path taken from one state to another
ex. heat and work

Question 32

in size exclusion chromatography, larger proteins travel —- than smaller proteins

Answer 32

FASTER

Question 33

in SDS page, larger proteins travel —- than smaller proteins

Answer 33

slower!!

Question 34

crude sample

Question 35

total yield

Answer 35

how much of the desired product is obtained following purification

Question 36

total yield of a protein can be determined by calculating ——-

Answer 36

total activity (u) of the purified protein

Question 37

total activity formula

Answer 37

Question 38

protein purity is represented by —-

Answer 38

specific activity

Question 39

specific activity

Answer 39

a ratio of the activity of the desired protein to the total mass of protein obtained from purification

Question 40

specific activity units

Answer 40

activity (u) / total mass (g)

Question 41

percent yield equation

Answer 41