Lecture 7 - Glycolysis

Question 1

Where is glucose entry insulin dependent (i.e. in what cells?)?

Answer 1

adipose tissue, muscle

Question 2

Glucokinase is found in:

A. Liver
B. Pancreatic B cells
C. All other cells
D. None of these
E. More than one of these

Answer 2

E - glucokinase is found in the liver and pancreatic B cells.

Question 3

Does glucokinase or hexokinase have a lower Km?

Answer 3

Hexokinase (Km = 0.1 mM)

Question 4

Does glucokinase or hexokinase have a higher Vmax?

Answer 4

Glucokinase

Question 5

Hexokinase in cells such as the brain and RBCs is always saturated. Only the inhibition of its product, ________, keeps its activity below Vmax.

Answer 5

Glu-6-P

Question 6

Pancreatic B cells respond to elevated glucose by secreting:

Answer 6

insulin

Question 7

The role of glycolysis in the ______ is to supply energy for muscle contraction.

Answer 7

muscle

Question 8

If there is a deficiency in __________ the result is hemolytic anemia.

Answer 8

pyruvate kinase

Question 9

Glycolytic enzymes are located where?

A. Cytosol
B. Mitochondrial matrix
C. Ribosome

Answer 9

A

Question 10

Which of the following enzymes is directly used in generating 1 NADH?

A. Hexokinase
B. PFK-1
C. Glyceraldehyde-3-dehydrogenase (GAPDH)
D. Phosphoglycerate kinase
E. Pyruvate kinase

Answer 10

C. The GAPDH enzyme generates 1 NADH (2/glucose molecule).

Question 11

Which of the following enzymes is directly used in generating 1 ATP?

A. Hexokinase
B. PFK-1
C. Glyceraldehyde-3-dehydrogenase (GAPDH)
D. Phosphoglycerate kinase
E. None of these

Answer 11

D. Phophoglycerate kinase generates 1 ATP (2/glucose).

Question 12

Which of the following enzymes directly requires 1 ATP?

A. PFK-1
B. Glyceraldehyde-3-dehydrogenase (GAPDH)
C. Phosphoglycerate kinase
D. Pyruvate kinase

Answer 12

A.

Question 13

Which of the following enzymes is directly used in generating 1 ATP?

A. Hexokinase
B. PFK-1
C. Glyceraldehyde-3-dehydrogenase (GAPDH)
D. Pyruvate kinase

Answer 13

D. Pyruvate kinase is used to generate 1 ATP (2/glucose).

Question 14

Glyceraldehyde-3-P dehydrogenase (GAPDH) generates an NADH, which must be __________ in order to be reused to continue glycolysis.

Answer 14

oxidized

Question 15

In aerobic conditions, the ETC and oxygen function to oxidize NADH generated by GAPDH so it can be recycled.

In anaerobic conditions, __________ converts pyruvate to lactate, and oxidizes the NADH back to NAD+ so that glycolysis continues.

Answer 15

lactate dehyrdogenase

Question 16

Aerobic glycolysis generates 2 pyruvate, 2 NADH, and 2 ATP.

How is anaerobic glycolysis different?

A. No pyruvate generated
B. 1 NADH generated
C. 1 pyruvate generated
D. No NADH generated
E. No ATP generated

Answer 16

D - pyruvate is reduced to lactate to regenerate NAD+ so no net NADH production.

Question 17

______ is the rate-limiting step in glycolysis. It catalyzes the reaction of fru-6-P converted to fru-1,6-BP.

Answer 17

PFK-1

Question 18

With what mechanism does PFK-1 regulate glycolysis?

Answer 18

Allosteric effectors work by changing the affinity of PFK-1 for the substrate.

Question 19

PFK-1 is activated by ______ in the liver, which has increased levels with insulin.

A. AMP
B. ADP
C. Fru-2,6-P2
D. Alanine

Answer 19

C. Fru-2,6-P2 is a signaling molecule which has increased levels by insulin and decreased levels by glucagon.

Question 20

In the liver, pyruvate kinase is covalently regulated by:

A. F-1,6-P2
B. ATP
C. ADP
D. Alanine
E. cAMP-dependent protein kinase

Answer 20

E - cAMP-dependent protein kinase inhibits the action of alanine in the liver.

Question 21

Glucose-6-P is an intermediate in glycolysis but also in the ______ pathway.

Answer 21

Pentose Phosphate Pathway