Metabolic Processes Part 1

Question 1

Rate limiting step in glycolysis

Answer 1

Step 3 catalyzed by PFK-1

Question 2

Location of glycolysis

Answer 2

Cytosol

Question 3

Product of glycolysis

Answer 3

2 molecules of pyruvate from 1 molecule of glucose

Question 4

ATP losses at which steps in glycolysis?

Answer 4

Step 1 catalyzed by hexokinase
Step 3 catalyzed phosphofructokinase

Question 5

ATP gains at which steps in glycolysis?

Answer 5

Step 7 catalyzed by phosphoglycerate kinase
Step 10 catalyzed by pyruvate kinase

Question 6

Total ATP yield in glycolysis (gross)

Answer 6

4 ATPs

Question 7

Total ATP yield in glycolysis (net)

Answer 7

2 ATPs

Question 8

NADH yield at which steps in glycolysis?

Answer 8

Step 6 catalyzed by glyceraldehyde-3-phosphate dehydrogenase

Question 9

Total NADH yield in glycolysis

Answer 9

2 NADH

Question 10

What are the irreversible steps in glycolysis?

Answer 10

Steps 1 catalyzed by hexokinase
Step 3 catalyzed by phosphofructokinase
Step 10 catalyzed by pyruvate kinase

Question 11

What is glycolysis for?

Answer 11

For the breakdown of glucose

Question 12

What are the substrates of glycolysis?

Answer 12

Glucose, 1,3-biphosphoglycerate, phosphoenolpyruvate

Question 13

What are the end products of glycolysis

Answer 13

2 molecules of pyruvate

Question 14

3 fates of pyruvate

Answer 14

Acetyl COA
Lactate
Ethanol

Question 15

In what condition would the Acetyl-COA pathway proceed?

Answer 15

Aerobic conditions in humans, animals, and microorganisms

Question 16

In what condition would the lactate pathway proceed?

Answer 16

Anaerobic conditions in humans, animals, and some microorganisms

Question 17

In what condition would the ethanol pathway proceed?

Answer 17

Anaerobic conditions in some microorganisms

Question 18

Acetyl-COA pathway is also known as?

Answer 18

Pre-Krebs cycle

Question 19

Describe the first fate of pyruvate

Answer 19

Pyruvate + COA-SH + NAD+ -[Pyruvate dehydrogenase complex] -> Acetyl-COA + NADH + CO2

Question 20

Describe the second fate of pyruvate

Answer 20

Pyruvate + NADH + H+ -[Lactate dehydrogenase]-> Lactate + NAD+

Question 21

Describe the third fate of pyruvate

Answer 21

Pyruvate -[Pyruvate decarboxylase]-> Acetaldehyde -[Alcohol dehydrogenase; NADH to NAD+]-> Ethanol

Question 22

Location of the Pre-Krebs cycle

Answer 22

Mitochondrial matrix

Question 23

Enzymes involved in the pyruvate dehydrogenase complex

Answer 23

Pyruvate decarboxylase
Dihydrolipoyl transacetylase
Dihydrolipoyl dehydrogenase

Question 24

Rate limiting step in Kreb’s cycle

Answer 24

Step 3 catalyzed by isocitrate dehydrogenase

Question 25

Location of Kreb's Cycle

Answer 25

Mitochondrial matrix

Question 26

Final products of Kreb's Cycle

Answer 26

Step 3: NADH and CO2 Step 4: NADH and CO2 Step 5: GTP Step 6: FADH2 Step 8: NADH

Question 27

Only step that produces NADH in glycolysis; only oxidative phosphorylation step

Answer 27

Step 6 catalyzed by phosphoglycerate kinase

Question 28

The only substrate-level phosphorylation step of Kreb's cycle

Answer 28

Step 5 catalyzed by succinyl-COA synthetase

Question 29

What is Kreb's cycle for?

Answer 29

The central hub/ common pathway; for energy/ ATP generation

Question 30

What are the substrates of Kreb's cycle?

Answer 30

Acetyl-COA and succinyl-COA

Question 31

How much is the energy yield in Kreb's cycle?

Answer 31

1 GTP, 3 NADH, 1 FADH2

Question 32

5 complexes in the ETC

Answer 32

Complex 1: NADH-CoQ reductase Complex 2: Succinate-CoQ-reductase Complex 3: CoQ/ ubiquinone cytochrome C reductase Complex 4: Cytochrome C oxidase Complex 5: ATP synthase

Question 33

How many ATP is yielded in the complete oxidation of glucose using the MA shuttle?

Answer 33

32

Question 34

How many ATP is yielded in the complete oxidation of glucose using the G3P shuttle?

Answer 34

30

Question 35

How many ATP is yielded in glycolysis in anaerobic conditions?

Answer 35

2

Question 36

Inhibitors of Complex 1

Answer 36

Rotenone and Amytal e- transport inhibitor

Question 37

Complex 3 inhibitors

Answer 37

Antimycin A e- transport inhibitor

Question 38

Complex 4 inhibitors

Answer 38

Cyanide, carbon monoxide, azide e- transport inhibitors

Question 39

Inhibitors of Complex 5

Answer 39

Oligomycin Inhibits ATP synthase