Exam 3 TEST questions

Question 1

the first substrate level phosphorylation in glycolysis produces

Answer 1

Produces 3-phosphoglycerate as a product

Question 2

All of the following are part of the Cori cycle except:
A. lactate is produced by anaerobic glycolysis in a number of tissues
B. Lactate travels to the liver in the bloodstream
C. Lactate is converted to glucose in the liver
D. ATP is produced by the conversion of lactate to glucose
E. Glucose travels in the bloodstream from the liver to other tissues

Answer 2

D. ATP is produced by the conversion of lactate to glucose

**this does not happen

Question 3

What is true about oxidation reduction reactions?

Answer 3

-every oxidation must be accompanied by a reduction

Question 4

If glucose labeled with 14C at C-2 were metabolized in the liver, the first radioactive pyruvate formed would be labeled in:

Answer 4

-its carbonyl carbon

Question 5

Glucose labeled with 14C at C-1 (aldehyde carbon) were metabolized in liver, first radioactive pyruvate formed would be labeled in:

Answer 5

-methyl carbon

Question 6

In comparison with the resting state, actively contracting human muscle tissue has a

Answer 6

-higher rate of lactate formation

Question 7

An enzyme used in both glycolysis and gluconeogenesis is:
A. 3-phosphoglycerate kinase
B. glucose 6-phosphatase
C. hexokinase
D. Phosphofructokinase-1
E. Pyruvate kinase

Answer 7

A. 3-phosphoglycerate kinase

Question 8

If you were given ΔG0’ for a reaction, what equation could you use to calculate ΔG?

Answer 8

ΔG0’ = -RT ln Q + ΔG

Question 9

anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by net gain of:

Answer 9

2 mol of ATP

Question 10

Which of the following compounds cannot serve as the starting material for the synthesis of glucose via gluconeogenesis:
A. acetate 
B. glycerol
C. lactate 
D. oxaloacetate 
E. a-ketoglutarate

Answer 10

A. acetate

Question 11

Which one of the following statements about gluconeogenesis is false?

A) For starting materials, it can use carbon skeletons derived from certain amino acids.
B) It consists entirely of the reactions of glycolysis, operating in the reverse direction.
C) It employs the enzyme glucose 6-phosphatase.
D) It is one of the ways that mammals maintain normal blood glucose levels between meals.
E) It requires metabolic energy (ATP or GTP).

Answer 11

B) It consists entirely of the reactions of glycolysis, operating in the reverse direction.

Question 12

With what enzyme does GTP enter the reaction?

Answer 12

PEP carboxykinase

Question 13

Gluconeogenesis must use “bypass reactions” to circumvent three reactions in the glycolytic pathway that are highly exergonic and essentially irreversible. Reactions carried out by which three of the enzymes listed must be bypassed in the gluconeogenic pathway?

Answer 13

• Hexokinase
• Phosphofructokinase-1
• Pyruvate kinase

Question 14

Glycogen is converted to monosaccharide units by:

Answer 14

glycogen phosphorylase

Question 15

the synthesis of glycogen, starch, and sucrose all:
A. involve addition of a sugar residue at the reducing end of the growing polymer
B. take place in liver and muscle of mammals
C. use sugar nucleotide as substrate

Answer 15

C. Use a sugar nucleotide as substrate

Question 16

Which of the following is not one of the general types of signaling mechanisms found in multicellular organisms?

Select one:

a. Receptor cAMP cyclases
b. Adhesion receptors
c. Gated ion channels
d. G protein-coupled receptors
e. Receptor tyrosine kinases

Answer 16

a. Receptor cAMP cyclases

Question 17

Which of the following does not bind to heterotrimeric G proteins?

A) GTP-GDP exchange factors (GEFs)
B) GTPase activating proteins (GAPs)
C) GPCRs
D) cGMP
E) GDP	
D) cGMP

Answer 17

D) cGMP

Question 18

Which of the following is not a feature of signal transduction?

A) Integration of multiple pathways toward the same downstream response
B) Signal amplification
C) Covalent binding between the ligand and the receptor
D) Desensitization or adaptation of the receptor
E) Variable affinity for different signaling components

Answer 18

C) Covalent binding between the ligand and the receptor

Question 19

Which ONE of the following statements about starch and glycogen is false?

A) Amylose is unbranched; amylopectin and glycogen contain many (alpha1→ 6) branches.
B) Both are homopolymers of glucose.
C) Both serve primarily as structural elements in cell walls.
D) Both starch and glycogen are stored intracellularly as insoluble granules.
E) Glycogen is more extensively branched than starch.

Answer 19

C) Both serve primarily as structural elements in cell walls.

Question 20

Which of the following statements concerning signal transduction by the insulin receptor is not correct?

A) Activation of the receptor protein kinase activity results in the activation of additional protein kinases.
B) Binding of insulin to the receptor activates a protein kinase.
C) Binding of insulin to the receptor results in a change in its quaternary structure.
D) The receptor protein kinase activity is specific for tyrosine residues on the substrate proteins.
E) The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.

Answer 20

-E) The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.

Question 21

Autophosphorylation of receptor tyrosine kinases depends on which of the following?
Select one:
a. Ligaind binding
b. ATP
c. All of the above
d. Dimerization of the receptor
e. Transmission of conformational changes through the membrane

Answer 21

C. All the above

Question 22

An example of a glycerophospholipid that is involved in cell signaling is:
A. Arachidoninic acid
B. ceramide
C. phosphatidylinositol
D. testosterone
E. Vitamin A (retinol)

Answer 22

C. phosphatidylinositol

Question 23

what inhibits Fructose Bisphosphatase-1?

Answer 23

-fructose 2,6-bisphosphate and AMP

Question 24

Fructose 2,6-bisphosphate signals

Answer 24

• high [Glucose]

- stimulates glycolysis