3. Metabolic pathways and ATP production I

Question 1

How is the high activation energy in combustion of glucose overcome?

Answer 1

By having multiple enzyme-catalysed reactions with lower AEs

Question 2

Where does glycolysis occur?

Answer 2

Cytoplasm

Question 3

What type of reaction is glycolysis?

Answer 3

Anaerobic

Question 4

What are the 2 main concepts I glycolysis?

Answer 4

Formation of high energy compound (invest ATP)

Splitting of high energy compound (produce ATP)

Question 5

What are the products of glycolysis?

Answer 5

2 X Pyruvate (C)
2 X ATP
2 X NADH

Question 6

How many ATP are generated from glycolysis?

Answer 6

4 ATP generated
But 2 ATP used
Net gain = 2 ATP

Question 7

What do all kinases in glycolysis catalyse?

Answer 7

Transfer of a phosphate group from a donor onto a substrate

Question 8

Which steps of glycolysis use and produce ATP?

Answer 8

1. Glucose -> Glucose-6-Phosphate (-ATP)
2. Fructose-6-phosphate -> Fructose-1,6-bisphosphate (-ATP)
3. 1,3-bisphosphoglycerate -> 3-phosphoglycerate (+ 2 ATP)
4. Phosphoenolpyruvate ->Pyruvate (+ 2 ATP)

Question 9

How many separate reactions are involved in glycolysis?

Answer 9

10

Question 10

What is substrate level phosphorylation and when does this occur in glycolysis?

Answer 10

Formation of ATP by direct transfer of high-energy phosphate intermediate to ADP
Occurs in step 7 and 10 of glycolysis

Question 11

How can NAD+ levels be replenished anaerobically?

Answer 11

Pyruvate fermented to ethanol (Yeasts)

Pyruvate used to generate lactate (mammals)

Question 12

What is required for Pyruvate to be fermented to ethanol?

Answer 12

Pyruvate decarboxylase

Alcohol dehydrogenase

Question 13

What is required for Pyruvate to be used to generate lactate?

Answer 13

Lactate dehydrogenase (LDH)

Question 14

Where is LDH found?

Answer 14

In cells of heart, muscles, brain, liver, kidney, lungs

Question 15

What can increased levels of LDH indicate?

Answer 15

Stroke
Heart attack
Hepatitis
Injury

Question 16

What buffers the demand for phosphate in muscles?

Answer 16

Creatine phosphate

Question 17

What is produced when creatine kinase acts on creatine phosphate?

Answer 17

Creatine

ATP

Question 18

How can creatine kinase be used diagnostically?

Answer 18

Creatine kinase leaks into blood when muscle is damaged

Can identify heart attack or extent of muscular disease

Question 19

Where does generation of Acetyl CoA occur?

Answer 19

Mitochondria

Question 20

What type of reaction is the generation of Acetyl CoA?

Answer 20

Aerobic

Question 21

What are the 3 fates of pyruvate?

Answer 21

Alcoholic fermentation
Generation of lactate
Generation of Acetyl-CoA

Question 22

Equation for generation of Acetyl CoA

Answer 22

Pyruvate + CoA -> Acetyl CoA + CO2

Question 23

What is required for generation of Acetyl CoA?

Answer 23

Pyruvate dehydrogenase complex

Question 24

What does the Pyruvate dehydrogenase complex consist of?

Answer 24

3 Enzymes

5 Co-factors

Question 25

What are the 3 enzymes in the Pyruvate dehydrogenase complex?

Answer 25

Lipoamide Reductase Transacetylase
Dihydrolipoyl Dehydrogenase
Pyruvate Decarboxylase

Question 26

What are the 5 co-factors in the Pyruvate dehydrogenase complex?

Answer 26

Thiamine pyrophosphate
Lipoamide
FAD
CoA
NAD+

Question 27

Which of the co-factors in the Pyruvate dehydrogenase complex are prosthetic groups (permanent)?

Answer 27

Thiamine pyrophosphate
Lipoamide
FAD

Question 28

What do the 3 enzymes of the Pyruvate dehydrogenase complex work together to do?

Answer 28

Generate an acetyl group and transfer it to CoA so Acetyl CoA can enter the TCA cycle
Regenerate active PDH complex for another series of reaction

Question 29

Where does acetyl CoA go once produced and what does it do?

Answer 29

Enters TCA cycle,

Forms ATP by oxidative phosphorylation