glycolysis

Question 1

Where are all the enzymes of glycolysis located?

Answer 1

In the cytosol.

Question 2

What is the general mechanism for ATP generation in glycolysis?

Answer 2

Rearrangement of phosphorylated monosaccharides into high-energy compounds that transfer phosphate to ADP.

Question 3

What is substrate-level phosphorylation?

Answer 3

The direct transfer of a phosphate group from an intermediate to ADP, forming ATP.

Question 4

Why must ATP be used after being generated in glycolysis?

Answer 4

To regenerate ADP, which is required to sustain glycolysis.

Question 5

How does glucose enter glycolysis after being transported into the cell?

Answer 5

It is phosphorylated to glucose-6-phosphate by hexokinase, using ATP as a phosphate donor.

Question 6

Is the phosphorylation of glucose reversible?

Answer 6

No, it is irreversible under physiological conditions.

Question 7

What inhibits hexokinase?

Answer 7

Its product, glucose-6-phosphate (allosteric inhibition).

Question 8

What is the difference between hexokinase and glucokinase?

Answer 8

Hexokinase (in most tissues) has a low Km (high affinity) and is inhibited by glucose-6-phosphate. Glucokinase (in the liver) has a high Km (low affinity) and is NOT inhibited by glucose-6-phosphate.

Question 9

Where is glucokinase found, and how does it function?

Answer 9

In the liver, with a higher Km than normal plasma glucose, allowing it to function when glucose levels are high.

Question 10

How is glucose transport regulated in muscle and adipose tissue?

Answer 10

It is stimulated by insulin.

Question 11

How is glucose used in muscle?

Answer 11

For glycolysis or glycogen synthesis.

Question 12

How is glucose used in adipose tissue?

Answer 12

For lipogenesis.

Question 13

Why is glucose transport important in glycolysis regulation?

Answer 13

It acts as a barrier when transport activity is low, limiting glucose uptake and overall glycolysis rate.

Question 14

Insulin-dependent glucose transporter?

Answer 14

GLUT-4

Question 15

Glucose transporter in erythrocytes?

Answer 15

GLUT-1

Question 16

Site of glycolysis in the cell?

Answer 16

Cytosol

Question 17

End product of aerobic glycolysis?

Answer 17

Pyruvate

Question 18

End product of anaerobic glycolysis?

Answer 18

Lactate

Question 19

Enzyme converting glucose to glucose-6-phosphate?

Answer 19

Hexokinase

Question 20

Rate-limiting enzyme of glycolysis?

Answer 20

PFK-1

Question 21

Enzyme converting phosphoenolpyruvate (PEP) to pyruvate?

Answer 21

Pyruvate kinase

Question 22

Type of phosphorylation in glycolysis?

Answer 22

Substrate-level

Question 23

Number of ATP molecules produced per glucose in glycolysis?

Answer 23

2

Question 24

Tissue where insulin resistance reduces GLUT-4?

Answer 24

Muscle (also Adipose)

Question 25

Glycolysis pathway also called?

Answer 25

Embden-Meyerhof

Question 26

Rate-limiting enzyme of gluconeogenesis?

Answer 26

Fructose-1,6-bisphosphatase

Question 27

Energy source in hypoxic cancer cells?

Answer 27

Glycolysis

Question 28

Glucose-6-phosphate inhibits which enzyme?

Answer 28

Hexokinase

Question 29

Rate-limiting enzyme of glycolysis?

Answer 29

PFK-1

Question 30

Enzyme inhibited by glucose-6-phosphate?

Answer 30

Hexokinase

Question 31

Liver enzyme that phosphorylates glucose?

Answer 31

Glucokinase

Question 32

PFK-1 activator that overrides ATP inhibition?

Answer 32

Fructose 2,6-bisphosphate

Question 33

Enzyme that synthesizes fructose 2,6-bisphosphate?

Answer 33

PFK-2

Question 34

Enzyme that degrades fructose 2,6-bisphosphate?

Answer 34

Fructose 2,6-bisphosphatase

Question 35

PFK-2 is active in which state?

Answer 35

Dephosphorylated

Question 36

Pyruvate kinase is inactivated by?

Answer 36

Phosphorylation

Question 37

Hormone that inhibits hepatic glycolysis?

Answer 37

Glucagon

Question 38

Second messenger controlling PFK-2 activity?

Answer 38

cAMP

Question 39

RBC pathway that produces 2,3-BPG?

Answer 39

Rapaport-Leubering cycle

Question 40

Enzyme converting 1,3-BPG to 2,3-BPG?

Answer 40

Bisphosphoglycerate mutase

Question 41

Enzyme hydrolyzing 2,3-BPG?

Answer 41

Bisphosphoglycerate phosphatase

Question 42

Percentage of glycolytic glucose shunted to 2,3-BPG synthesis?

Answer 42

15-25%

Question 43

Effect of 2,3-BPG on hemoglobin?

Answer 43

Decreases oxygen affinity

Question 44

Condition where 2,3-BPG increases?

Answer 44

Hypoxia

Question 45

Effect of high altitude on 2,3-BPG?

Answer 45

Increases

Question 46

Major tissue needing 2,3-BPG for oxygen delivery?

Answer 46

Fetal tissue

Question 47

Pathway glycolysis follows in RBCs to avoid ATP production?

Answer 47

2,3-BPG shunt

Question 48

Why does RBC glycolysis prioritize 2,3-BPG over ATP?

Answer 48

Oxygen unloading