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Quiz on: Glycogen-Metabolism/Gluconeogenesis
1. Which of the following is not a mechanism for altering the flux of metabolites through the rate-determining step of a pathway?
a) Covalent modification of the enzyme.
b) Genetic control of the enzyme concentration.
c) Diffusional coupling between adjacent active sites.
d) Allosteric control of the enzyme activity.
e) Coordinate regulation of synthetic and degradative steps in the same pathway.
2. The breakdown of glycogen to form glucose occurs
a) in the liver by phosphorolysis.
b) in the muscles by phosphorolysis.
c) in the liver by hydrolysis.
d) in the muscles by hydrolysis.
e) a and b are both correct.
3. The precursor to glycogen in the glycogen synthase reaction is
a) glucose-1-P.
b) glucose-6-P.
c) UDP-glucose.
d) UTP-glucose.
e) None of the above.
4. Which of the following steps from glycolysis is performed by a different enzyme in gluconeogenesis?
a) Isomerase
b) Phosphofructokinase (PFK)
c) Glyceraldehyde-3-P dehydrogenase
d) enolase
e) aldolase
5. Fructose-2,6-bisphosphate (F2,6P)
a) inhibits phosphofructokinase.
b) activates fructose-1,6-bisphosphatase.
c) activates phosphofructokinase.
d) inhibits fructose-1,6-bisphosphatase.
e) c and d are both correct.
6. The active form of glycogen ___ is phosphorylated; the active form of glycogen ___ is dephosphorylated.
a) hydrolase; dehydrogenase
b) dehydrogenase; hydrolase
c) hydrolase; semisynthase
d) phosphorylase; synthase
e) synthase; phosphorylase
1. In a eukaryotic cell, the enzymes of glycolysis are located in the
a) plasma membrane.
b) inner mitochondrial membrane.
c) cytosol.
d) mitochondrial matrix.
e) intermembrane space.
2. For each molecule of glucose converted to pyruvate in the glycolytic pathway __ molecules of ATP are used initially (Stage 1) and __ molecules of ATP are produced (Stage 2) for an overall yield of __ molecules of ATP/glucose. The "ATP math" is:
a) -2 + 4 = 2
b) -1 + 4 = 3
c) -2 + 5 = 3
d) -1 + 2 = 1
e) 2 + 2 = 4
3. Energy released by oxidation of glucose is stored as
a) a concentration gradient across a membrane.
b) ATP.
c) NADH.
d) ADP.
e) both b and c are correct.
4. Phosphofructokinase, the major flux-controlling enzyme of glycolysis is allosterically inhibited by ___ and activated by ___.
a) AMP Pi
b) ADP AMP
c) citrate ATP
d) ATP PEP
e) ATP ADP
5. The regulation of the glycolytic pathway involves
a) feedback inhibition by ATP.
b) allosteric inhibition by ATP.
c) allosteric stimulation by ADP.
d) All three are correct.
e) Only a and b are correct.
6. Enolase catalyzes
a) the oxidation of an alkene to an alcohol.
b) the reduction of an alkene to an alcohol.
c) the conversion of an alkene to an alcohol.
d) the conversion of an aldose to a ketose.
e) none of the above.
7. The major energy generating step during glycolysis is
a) hexokinase.
b) phosphofructokinase.
c) glyceraldehyde-3-P dehydrogenase.
d) phosphoglycerate kinase.
e) pyruvate kinase.
8. If the concentration of the reactants is higher than the equilibrium concentration, then:
a) More reactants will form.
b) The Gibbs free energy will be negative.
c) More product will form.
d) The Gibbs free energy will be positive.
e) Both b and c are correct.
Quiz on Lecture 9: Protein Tertiary & Quaternary Structure
1. Which of the following is an example of tertiary structure in a protein?
A
polyalanine.
B
a multimeric protein.
C
an [FONT=''SYMBOL'']a[/font]-helix.
D
a [FONT=''SYMBOL'']b[/font]-pleated sheet.
E
a globular domain.
2. An "oil drop with a polar coat" is a metaphor referring to the three dimensional structure of:
A
fibrous proteins.
B
collagen.
C
globular proteins.
D
silk protein.
E
The first and the second choice are both correct.
3. The portion of proteins having the highest mobility are
A
[FONT=''SYMBOL'']a[/font]-helices.
B
[FONT=''SYMBOL'']b[/font]-sheets.
C
peptide bonds.
D
surface side chains.
E
aliphatic groups.
4. Which of the following is most correct:
A
Charged amino acids are never buried in the interior of a protein.
B
Charged amino acids are seldom buried in the interior of a protein.
C
All hydrophobic amino acids are buried when a protein folds.
D
Tyrosine is only found in the interior of proteins.
E
Glycine is rarely found in proteins because it is too destabilizing.
5. Disulfide bonds most often stabilize the native structure of:
A
extracellular proteins.
B
dimeric proteins.
C
hydrophobic proteins.
D
intracellular proteins.
E
multisubunit proteins.
6. Buried hydrophobic sidechains in a globular protein fit into a "hole" formed by the sidechains of
A
1-3 other amino acids.
B
precisely six other amino acids.
C
5-7 other amino acids.
D
9-12 other amino acids.
E
13-15 other amino acids.
7. The fact that the core of most globular proteins is composed of non-polar residues is because of
A
van der Waals interactions.
B
hydrogen bonds.
C
a favorable increase in conformational entropy.
D
the hydrophobic effect.
E
favorable electrostatic interactions.
8. The fact that the core of most globular proteins is tightly packed is due to
A
the hydrophobic effect.
B
hydrogen bonding.
C
electrostatic effects.
D
van der Waals forces.
E
configurational entropy
Linear Mode
