Metabolic Pathways and ATP Production I

Question 1

What are simple sugars such as glucose derived from?

Answer 1

Polysaccharides

Question 2

What two things are fats broken down into?

Answer 2

Fatty acids and glycerol

Question 3

What are the three main stages of metabolism?

Answer 3

Glycolysis, TCA cycle, and oxidative phosphorylation

Question 4

How is the large activation energy of the combustion of glucose overcome?

Answer 4

By having several enzyme catalysed reactions with smaller activation energies

Question 5

What is ligation?

Answer 5

Forming covalent bonds with ATP cleavage

Question 6

What is the overall reaction of glycolysis?

Answer 6

4 ATP produced, 2 ATP used, 2 pyruvates produced

Question 7

How many steps in glycolysis?

Answer 7

10

Question 8

What is the first step of glycolysis? Reactant: glucose

Answer 8

Glucose to glucose 6 phosphate, using hexokinase (or glucokinase in liver) and 1 ATP.

Question 9

What is the second step of glycolysis? Reactant: glucose 6 phosphate

Answer 9

Glucose 6 phosphate to fructose 6 phosphate using phosphoglucose isomerase

Question 10

What is the third step of glycolysis? Reactant: fructose 6 phosphate

Answer 10

Fructose 6 phosphate to fructose 1 6 bisphosphate using phosphofructokinase and 1 ATP.

Question 11

What is the fourth step of glycolysis? Reactant: fructose 1 6 bisphosphate

Answer 11

Fructose 1 6 bisphosphate to glyceraldehyde 3 phosphate and dihydroxyacetone phosphate using aldolase

Question 12

What is the fifth step of glycolysis? Reactant: dihydroxyacetone phosphate

Answer 12

Dihydroxyacetone phosphate to glyceraldehyde 3 phosphate using triose phosphate isomerase

Question 13

What has happened by the halfway point of glycolysis? (3)

Answer 13

1 mole of glucose has produced 2 moles of glyceraldehyde 3 phosphate, 2 ATP have been used and none has been produced

Question 14

What is the sixth step of glycolysis? Reactant: glyceraldehyde 3 phosphate

Answer 14

Glyceraldehyde 3 phosphate to 1 3 bisphosphoglycerate using glyceraldehyde 3 phosphate dehydrogenase. NADH is generated

Question 15

What is the seventh step of glycolysis? Reactant: 1 3 bisphosphoglycerate

Answer 15

1 3 bisphosphoglycerate to 3 phosphoglycerate using phosphoglycerate kinase. 1 ATP is produced

Question 16

What is the eighth step of glycolysis? Reactant: 3 phosphoglycerate

Answer 16

3 phosphoglycerate to 2 phosphoglycerate using phosphoglycerate mutase

Question 17

What is the ninth step of glycolysis? What type of reaction? Reactant: 2 phosphoglycerate

Answer 17

2 phosphoglycerate to phosphoenolpyruvate using enolase. Dehydration.

Question 18

What is the tenth and final step of glycolysis? Reactant: phosphoenolpyruvate

Answer 18

Phosphoenolpyruvate to pyruvate using pyruvate kinase. 1 ATP is generated.

Question 19

Which steps produce ATP?

Answer 19

7 and 10

Question 20

Which step produces NADH?

Answer 20

6

Question 21

What are the three possible fates of pyruvate?

Answer 21

Alcoholic fermentation by yeast under anaerobic conditions, generation of lactate and generation of acetyl CoA

Question 22

What is creatine phosphate?

Answer 22

A large reservoir of phosphate which can be used to phosphorylate ADP to ATP

Question 23

What does lactate dehydrogenase catalyse? What does the reaction produce?

Answer 23

The conversion of pyruvate to lactate and back, producing NAD+ to be used in glycolysis to make NADH

Question 24

What medical use does lactate dehydrogenase have?

Answer 24

Elevated levels indicate stroke, heart attack, liver disease, muscle injury…

Question 25

What medical use does creatine kinase have?

Answer 25

When muscle is damaged creatine kinase leaks into the bloodstream, indicating myocardial infarction, muscular disease, chest pain and carriers of muscular dystrophy

Question 26

How many enzymes are involved in the generation of acetyl CoA?

Answer 26

3

Question 27

How many co-factors are involved in the generation of acetyl CoA?

Answer 27

5

Question 28

Overall reaction of the pyruvate dehydrogenase complex?

Answer 28

Pyruvate + CoA + NAD+ --> acetyl CoA + CO2 + NADH

Question 29

What are the 3 enzymes involved in the pyruvate dehydrogenase complex?

Answer 29

Lipoamide reductase-transacetylase, dihydrolipoyl dehydrogenase and pyruvate decarboxylase

Question 30

What are the 5 co-factors involved in the pyruvate dehydrogenase complex?

Answer 30

Thiamine pyrophosphate (TPP), lipoamide, FAD, CoA NAD+

Question 31

What is the prosthetic group of pyruvate decarboxylase?

Answer 31

Thiamine pyrophosphate (TPP)

Question 32

What is the prosthetic group of lipoamide-reductase transacetylase?

Answer 32

Lipoamide

Question 33

What is the prosthetic group of dihydrolipoyl dehydrogenase?

Answer 33

FAD

Question 34

What is enzyme of thiamine pyrophosphate (TPP)?

Answer 34

Pyruvate decarboxylase

Question 35

What is enzyme of FAD?

Answer 35

Dihydrolipoyl dehydrogenase

Question 36

What is enzyme of lipoamide?

Answer 36

Lipoamide-reductase transacetylase

Question 37

What is thiamine pyrophosphate (TPP) derived from?

Answer 37

Vitamin B

Question 38

What is the first step in the pyruvate dehydrogenase complex?

Answer 38

Decarboxylation of pyruvate to give hydroxyethyl TPP. Gives out CO2.

Question 39

What is the second step in the pyruvate dehydrogenase complex?

Answer 39

Oxidation and transfer to lipoamide to give acetylipoamide

Question 40

What is the third step in the pyruvate dehydrogenase complex?

Answer 40

Transfer of the acetyl group to CoA to form acetyl CoA

Question 41

What is the fourth step in the pyruvate dehydrogenase complex?

Answer 41

Regeneration of oxidised lipoamide

Question 42

What is the fifth step in the pyruvate dehydrogenase complex?

Answer 42

Regeneration of oxidised FAD, generating NADH

Question 43

Summarise the pyruvate dehydrogenase complex in words

Answer 43

Pyruvate comes in attaches to TPP and loses a CO2. The mobile arm swings over picks up the acetyl group. CoA comes in and strips away the acetyl group. Then everything is restored to how it should be.