biochem mastery

Question 1

which type of interaction does NOT contribute to stabilization of the tertiary structure of a protein?

a) disulfide
b) phosphodiester
c) hydrogen
d) covalent

Answer 1

phosphodiester bond

Question 2

which type of inhibitor does NOT alter the Km/Vmax ratio of an enzyme?

a) competitive
b) uncompetitive
c) noncompetiive
d) mixed

Answer 2

uncompetitive because in uncompetitive both Km and Vmax are affected

Question 3

an enzyme is most effective as uncompetitive inhibitor if

I. substrate concentration is increased
II. substrate concentration is decreased
III. inhibitor concentration is decreased

Answer 3

II and III

Question 4

When looking for a peptide sequence that owed most likely be found in the transmembrane of a protein helix, look for…?

Answer 4

hydrophilic/ polar outside and most hydrophobic inside

Question 5

how many subunits in a protein is composed of…?

Answer 5

110 amino acid

Question 6

SDs page in reducing conditions lead to…

Answer 6

disulfide bonds

Question 7

which of the following separates protein base don their charge?

I. SDS. PAGE
II. Isoelectric focusing
III. Ion exchange chromatography
IV. Affinity chromatography

Answer 7

II and III

Question 8

which of the following compounds is NOT a gluconeogenic precursor or substrate?

lactate
glycerol
oxaloacetae
phosphogluconate

Answer 8

phosphogluconate

Question 9

under physiological conditions, increases activity of succinyl Coa synthetase will result in ..?

I. increased succinyl CoA
II. increases succinate
III. increased levels of GTP

Answer 9

II and III

Question 10

the pentose phosphate pathway result in :

a) NADPH used as reductive agent in cell. res.
B) NADPH used as oxidative agent in cell. res.
C NADH used as reductive agent in cell. res.
D) NADH used as oxidative agent in cell. res.

Answer 10

A + NADPH reduces sulfide bond

Question 11

The Vmax of enzymatic reaction is altered by what inhibitors?

I) competitive
II) nono competitive
III) uncompetitive
IV) mixed

Answer 11

II, III, IV

Question 12

In PPP which enzyme catalyzes production of 6- phosphogluconolactone?

a) glucose 6 phosphate dehydrogenase
b) 6 phosphogluconolactonase
c) phosphogluconate dehydrogenase
d) glycerol 3 phosphate dehydrogenase

Answer 12

A

d- glycolysis

Question 13

which experimental results confirm that compound 1 is an uncompetitive inhibitor of a particular enzyme/ in presence of compounds 1…

Answer 13

both KM and Vmax decrease

Question 14

A protein contains four disulfide bonds in order to break these bonds researchers added a minimum of:

• 2 moles of NADH
• 2 moles of NAD+
• 4 moles of NAD+
• 4 moles of NADH

Answer 14

4 moles of NADH

Question 15

which of the four DNA base pairs contains the largest number of hydrogen bond acceptors when involved in watson crick base pair?

Answer 15

cytosine

Question 16

Organic acids,HA, are only minimally deprotonated when added to pure water.
HA (aq) H+ + A-.
When dissolved in blood, however, HA fully dissociate. What factor can be used to explain this discrepancy?

a) in blood, the concentration of H+ (aq) is maintained at low levels by other equilibria.
b) in blood, the reaction is coupled to ATP hydrolysis to make it more favorable
c) in blood, the ionic strength of the solvent medium is much higher han pure water.
d) in blood, enzymes are used to catalyze the dissociation reaction.

Answer 16

A

Question 17

In oxidative phosphorylation, cytochrome c acts as:

a) 1 electron carrier
b) 2 electron carrier
c) 3 electron carrier
d) 4 electron carrier

Answer 17

a

Question 18

what does a primer need to be suitable for PCR?

Answer 18

lots of GC base pairs at 5’ and 3’ ends.

Question 19

In which phase of meiosis does nondisjunction occur?

Answer 19

anaphase I