Metabolism Biochemistry (Enzymes and pathways)

Question 1

What is metabolized in the mitochondria?

Answer 1

1. Fatty acid Beta oxidation
2. CoA production
3. TCA Cycle
4. Oxidative phosphorylation

Question 2

What is metabolized in the cytoplasm?

Answer 2

1. Glycolysis
2. Fatty acid synthesis
3. HMP Shunt
4. Protein synthesis
5. Steroid synthesis
6. Cholesterol synthesis

Question 3

What reactions can occur in both the mitochondria and the cytoplasm?

Answer 3

1. Heme synthesis
2. Urea cycle
3. Gluconeogensis

Question 4

What is the rate limiting enzyme of glycolysis?

Answer 4

Phosphofructokinase-1

Question 5

What is the rate limiting enzyme of gluconeogenesis?

Answer 5

Fructose-1,6-bisphosphatase

Question 6

What is the rate limiting enzyme of the TCA cycle?

Answer 6

Isocitrate dehydrogenase

Question 7

What is the rate limiting enzyme of glycogenesis?

Answer 7

Glycogen synthase

Question 8

What is the rate limiting enzyme of glycogenolysis?

Answer 8

Glycogen phosphorylase

Question 9

What is the rate limiting enzyme of the HMP Shunt?

Answer 9

G6PD

Question 10

What is the rate limiting enzyme of de novo pyrimidine synthesis?

Answer 10

Carbamoyl phosphate synthetase II

Question 11

What is the rate limiting enzyme of de novo purine synthesis?

Answer 11

Glutamine-PRPP-amidotransferase

Question 12

What is the rate limiting enzyme of urea cycle?

Answer 12

Carbamoyl phosphate synthetase I

Question 13

What is the rate limiting enzyme of fatty acid synthesis?

Answer 13

Acetyl-CoA carboxylase

Question 14

What is the rate limiting enzyme of fatty acid oxidation?

Answer 14

Carnitine acyltransferase I

Question 15

What is the rate limiting enzyme of ketogenesis?

Answer 15

HMG-CoA synthase

Question 16

What is the rate limiting enzyme of cholesterol synthesis?

Answer 16

HMG-CoA reductase

Question 17

How many ATP can be generated from glucose when the malate aspartate shuttle is used?

Answer 17

32

Question 18

How many ATP can be generated from glucose when the glycerol-3-P shuttle is used?

Answer 18

30

Question 19

What is the first step of glycolysis?

Answer 19

Glucose -> Glucose-6-P, means the glucose is trapped in the cell

Question 20

What enzyme catalyzes the first step of glycolysis?

Answer 20

1. Hexokinase in MOST tissues

2. gLucokinase in LIVER

Question 21

What enzyme that phosphorylates glucose is induced by insulin?

Answer 21

Glucokinase

Question 22

Glucose-6P ->Fructose-6P->Fructose-1,6BP is sent on through glycolysis if the person is in what state?

Answer 22

Fed state, insulin around

Question 23

Glucose-6P ->Fructose-6P->Fructose-1,6BP is sent on to what process if in the fasting state? What enzymes are involved?

Answer 23

Gluconeogenesis, FBPase-1 sends it back to F-6P

Question 24

What cofactor does arsenic inhibit?

Answer 24

Lipoic acid

Question 25

What builds up if there is a pyruvate dehydrogenase complex deficiency? What clinical findings present?

Answer 25

Lactate and Alanine -> Lactic acidosis and neurologic defects

Question 26

What reactions of the TCA cycle generate GTP?

Answer 26

Succinyl-CoA -> Succinate

Question 27

What reactions of TCA cycle generate NADH?

Answer 27

1. Isocitrate -> Alpha-ketogluterate
2. Alpha-ketogluterate ->Succinyl-CoA
3. Malate ->Oxaloacetate

Question 28

What reactions of the TCA cycle generate FADH2?

Answer 28

Succinate ->Fumarate

Question 29

What are the irreversible enzymes of Gluconeogenesis?

Answer 29

1. Pyruvate carboxylase
2. Phosphoenolpyruvate carboxykinase
3. Fructose -1,6-Bisphosphatase
4. Glucose-6-Phosphatase

Question 30

What is the use of the HMP Shunt? Where is it performed?

Answer 30

• Generates NADPH (reducing power)

- Liver, adrenal cortex, RBCs

Question 31

What agents can induce hemolysis in G6PD patients?

Answer 31

1. Fava beans
2. Sulfonamides
3. Primaquine