Glycolysis

Question 1

What is the preferred energy source for the brain in non-starvation conditions?

Answer 1

Glycolysis

Question 2

What is a crucial source of energy in anaerobic conditions?

Answer 2

Glycolysis

Question 3

What are the two general phases of glyclysis?

Answer 3

Energy investment
Energy production

Question 4

What are the general products of glycolysis?

Answer 4

ATP
NADH
Pyruvate - lactate

Question 5

What are the enzymes of the three irreversible reactions of glycolysis?

Answer 5

Hexokinase/glucokinase
PFK-1
Pyruvate kinase

Question 6

What are the metabolic pathways that G6P can be used for?

Answer 6

Glycolysis
Pentose phosphate pathway
Uronic acid pathway
Glycogenesis

Question 7

Out of hexokinase and glucokinase, what is inhibited by G6P?

Answer 7

Hexokinase

Question 8

What is caused by a hexokinase deficiency?

Answer 8

Hemolytic anemia

Question 9

What is the most important site of regulation in the glycolysis pathway?

Answer 9

PFK-1

Question 10

What are the priming reactions of glycolysis and what does that mean?

Answer 10

Catalyzed by hexokinase/glucokinase and PFK-1

Energy used

Question 11

What will occur with a PFK-1 deficiency?

Answer 11

Hemolytic anemia

Question 12

What cells lack mitochondria and perform anaerobic glycolysis?

Answer 12

RBCs

Question 13

What happens to NADH produced in glycolysis?

Answer 13

Has to be recycled, different pathways

Question 14

What does the fate of pyruvate produced by glycolysis depend on?

Answer 14

The availability of oxygen

Question 15

What happens to pyruvate in anaerobic conditions?

Answer 15

Reduced by lactate dehydrogenase to lactate using NADH to NAD+

Question 16

What are the tissues that typically produce lactate?

Answer 16

Skeletal muscle
RBCs
Brain
GI tract
Renal medulla
Retina
Skin

Question 17

Where is lactate usually taken up and oxidized?

Answer 17

Liver
Kidneys
Heart

Question 18

How much ATP is produced from glycolysis in anaerobic conditions?

Answer 18

Net 2 ATP

Question 19

How much ATP is produced from glycolysis in aerobic conditions?

Answer 19

Net 7 ATP

Question 20

What are the two ATP producing enzymes of glycolysis?

Answer 20

Phosphoglycerate kinase
Pyruvate kinase

Question 21

What enzyme of glycolysis produces NADH?

Answer 21

Glyceraldehyde 3-phosphate dehydrogenase

Question 22

What sugars can be oxidized via glycolysis?

Answer 22

Fructose
Galactose
Mannose
Glycerol

Question 23

What allows the unloading of oxygen in RBCs?

Answer 23

RL shunt

Question 24

What enzyme and reaction is bypassed in the RL shunt in RBCs?

Answer 24

Phosphoglycerate kinase

Question 25

What is provided by RL shunt to decrease Hgb affinity for oxygen?

Answer 25

2,3-bisphosphoglycerate

Question 26

What Hgb exhibits a lower affinity for 2,3-bisphosphoglycerate?

Answer 26

Fetal Hgb

Question 27

What is the result of pyruvate kinase deficiency?

Answer 27

Hemolytic anemia

Question 28

What deficiency would the presence of Heinz bodies indicate?

Answer 28

G6PD deficiency

Question 29

With what glycolytic enzyme deficiency would you see an increase in 2,3-bisphosphoglycerate?

Answer 29

PK deficiency

Question 30

What are clinical signs of pyruvate kinase deficiency?

Answer 30

Anemia Growth delay Failure to thrive Jaundice Mild-moderate splenomegaly

Question 31

What is lactic acidosis?

Answer 31

State of acidosis characterized by elevated plasma lactate concentration

Question 32

What causes lactic acidosis?

Answer 32

Circulatory insufficiency Severe anemia Inhibitors (carbon monoxide, cyanide) Alcohol PDH complex deficiency Severe exercise Von Gierke's disease

Question 33

How does fluoride inhibit glycolysis?

Answer 33

Inhibits enolase

Question 34

How does fluoride work in oral cavity to prevent cavities?

Answer 34

Inhibiting bacterial glycolysis

Question 35

What enzymes are infected in general by arsenic?

Answer 35

-SH group containing enzymes

Question 36

How does arsenate affect glycolysis?

Answer 36

Interfere with glyceraldehyde-3P dehydrogenase decreasing ATP and NADH production - competes with phosphate Does not inhibit pathway

Question 37

How does iodoacetate inhibit glycolysis?

Answer 37

Inhibits glyceraldehyde 3P dehydrogenase

Question 38

How does bromohydroxyacetone phosphate inhibit glycolysis?

Answer 38

Inhibits dihydroxyacetone phosphate

Question 39

How does oxamate inhibit glycolysis?

Answer 39

Inhibits lactate dehydrogenase

Question 40

How will the rate of glycolysis respond to hyperglycemia?

Answer 40

Increase

Question 41

How will the rate of glycolysis respond to the presence of insulin in the blood stream?

Answer 41

Increase

Question 42

How will the rate of glycolysis respond to hypoglycemia?

Answer 42

Decrease

Question 43

How will the rate of glycolysis response to glucagon in the blood stream?

Answer 43

Decrease

Question 44

What induces the transcription of the rate limiting enzymes of glycolysis?

Answer 44

Insulin

Question 45

What represses the transcription of the rate limiting enzymes of glycolysis?

Answer 45

Glucagon

Question 46

How does G6P affect hexokinase and glucokinase?

Answer 46

Inhibits hexokinase Does not inhibit glucokinase

Question 47

How does ATP affect PFK-1?

Answer 47

Allosteric inhibitor

Question 48

How does AMP affect PFK-1?

Answer 48

Reverses affect of ATP at high concentrations

Question 49

How does citrate regulate glycolysis?

Answer 49

Inhibits PFK-1

Question 50

How does fructose-2,6-bisphosphate affect glycolysis?

Answer 50

Allosteric activator of PFK-1 Inhibits fructose-1,6-bisphosphatase

Question 51

What activates PK?

Answer 51

AMP Fructose-1,6-bisphosphate

Question 52

What inhibits PK?

Answer 52

ATP Acetyl CoA Alanine

Question 53

How does covalent modification in the liver affect PK?

Answer 53

Phosphorylated PK is more strongly inhibited by ATP and alanine

Question 54

What is the Warburg Effect?

Answer 54

Lactate produced in presence of oxygen in tumors and other proliferating cells