Multiple Choice from Exams 1-4

Question 1

How does the dielectric constant after the electrostatic energy

Answer 1

inversely

Question 2

Which of the following is true of a buffer with a pKa of 8.0

Answer 2

at pH 6, the buffer would be completely protonated

Question 3

Relies on the chance charge separation of one atom to induce a dipole in a second atom

Answer 3

Van der Waals interactions

Question 4

Which amino acids have a side chain that is negatively charged at physiological pH

Answer 4

aspartate and glutamate

Question 5

Essential amino acids

Answer 5

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine 
Threonine
Tryptophan
Valine

Question 6

Which of the following is true of the peptide bond in naturally-occurring proteins

Answer 6

It has partial double bond characteristics

Question 7

Which of the following is true of protein structure

Answer 7

all proteins have tertiary structure

Question 8

What is true of a Ramachandran plot?

Answer 8

a. Secondary structure types have characteristics locations on a Ramachandran plot
b. Some locations on a Ramachandran diagram are not permitted for amino acids because of steric hindrance
c. It shows the combinations of torsion angle within a protein structure

Question 9

What is true of protein folding?

Answer 9

a. it is a random series of events that spontaneously results in the correct fold
b. the folded state of the protein is the lowest energy state
c. correct intermediate forms are progressively stabilized until the completely correct fold is reached

Question 10

A mutation in which protein results in the disorder epidermolysis bulls simplex (EBS)

Answer 10

keratin

Question 11

Which of the following trends is/are observed during protein purification

Answer 11

the specific activity increases with each purification step

Question 12

Nitrogenase transfers electrons from ferredoxin to N2 to make ammonia. What class of enzyme is this?

Answer 12

oxidoreductase

Question 13

Hexokinase has a Km of 0.9 mM for its substrate glucose. Glucokinase has a Km of 90 mM for glucose. Which enzyme has the highest affinity for glucose?

Answer 13

Hexokinase

Question 14

shift the T/R equilibrium for both allosteric models

Answer 14

allosteric effectors

Question 15

The influence of the substrate on allosteric enzymes to alter their T/R equilibrium

Answer 15

Cooperativity

Question 16

What is the molecular basis of gout?

Answer 16

Urate accumulates in the fluid and lining of joints causing inflammation. PRS catalysis at the active site is unchanged. PRS enzyme loses its feedback-inhibition response to purines

Question 17

Glyphosphate binds to the enzyme EPSP at the active site instead of the substrate molecule PEP and prevents catalysis. What type of inhibitor is it?

Answer 17

competitive

Question 18

Which of the following is true of the allosteric effectors of hemoglobin

Answer 18

a high concentration of H+ facilitates O2 release

Question 19

Which of the following best describes the molecular basis of ion channel selectivity?

Answer 19

Ion channels only allow one specific ion through their selectivity filter.

Question 20

Which of the following is true of biological membranes

Answer 20

membranes are highly impermeable to charged molecules

Question 21

Oxidize carbon fuels to generate ATP

Answer 21

catabolic pathways