7: Acetyl-CoA and the TCA Cycle

Question 1

Glycolysis summary

Answer 1

glucose to acetyl CoA

Question 2

TCA cycle summary

Answer 2

Acetyl CoA is oxidized to CO2 and electron carries NAD+ and FAD are reduced

Question 3

OXPHOS summary

Answer 3

electrons from fuel molecules are transferred to O2 and ATP is produced

Question 4

What enzymes catalyze redox reactions?

Answer 4

dehydrogenases

Question 5

What vitamin are NAD and NADP derived from?

Answer 5

Niacin (B3)

Question 6

What disease does a nutrition niacin deficiency cause in humans?

Answer 6

pellagra

Question 7

What disease does a nutrition niacin deficiency cause in dogs?

Answer 7

black tongue

Question 8

Where does glycolysis occur?

Answer 8

cytoplasm

Question 9

Where does the TCA cycle occur?

Answer 9

mitochondria

Question 10

3 metabolic destinations of pyruvate

Answer 10

1. acetyl CoA
2. lactate
3. alanine

Question 11

3 possible fates of acetyl CoA

Answer 11

1. TCA cycle
2. ketone bodies
3. sterols and fatty acids

Question 12

pyruvate dehydrogenase (PDH) complex structure

Answer 12

3 enzymes and many coenzymes

Question 13

What does a thiamine (B1) deficiency cause?

Answer 13

inability to oxidize pyruvate causing weakness and trouble walking

Question 14

Regulation of PDH

Answer 14

1. feedback inhibition
2. enzymatic regulation (PDH kinase or phosphatase)

Question 15

What does pyruvate dehydrogenase covert?

Answer 15

pyruvate to acetyl CoA

Question 16

Is the phosphorylated for of PDH active or inactive?

Answer 16

inactive

Question 17

PHD kinase effect on PHD

Answer 17

inhibits

Question 18

Phosphatase effect on PHD

Answer 18

restores activity

Question 19

Which molecules increase the activity of the kinase that phosphorylates PDH?

Answer 19

NADH and acetyl CoA

Question 20

Which molecules decrease the activity of the kinase that phosphorylates PDH?

Answer 20

CoASH, NAD+, ADP, pyruvate

Question 21

Which molecules increase the activity of the enzyme that DEphosphorylates PDH?

Answer 21

Mg2+ and Ca2+

Question 22

What dog breeds is exercise-induced collapse common in?

Answer 22

Clumber and Sussex Spaniels

Question 23

What causes exercise-induced collapse?

Answer 23

PDH phosphatase 1 deficiency

Question 24

What does Acetyl CoA combine with?

Answer 24

oxaloacetate

Question 25

What does Acetyl CoA and oxaloacetate combine to form?

Answer 25

isocitrate

Question 26

An abundance of ATP will ___ the TCA cycle in a feedback loop

Answer 26

inhibit

Question 27

What coenzymes is riboflavin (B2) a precursor of?

Answer 27

FAD and FMN

Question 28

Riboflavin deficiency will inhibit the TCA cycle causing what in dogs?

Answer 28

anorexia, weight loss, weakness, ataxia, collapse, and death

Question 29

What is citrate a precursor for?

Answer 29

fatty acid and sterol synthesis

Question 30

What is alpha-ketoglutarate a precursor for?

Answer 30

amino acid synthesis and neutrotransmitters

Question 31

What is oxaloacetate a precursor for?

Answer 31

amino acid synthesis

Question 32

Anaplerotic

Answer 32

“filling up” reactions in the TCA cycle to replenish intermediates

Question 33

When oxaloacetate is low, what can be directly concerted to it?

Answer 33

pyruvate

Question 34

What enzyme converts pyruvate to oxaloacetate?

Answer 34

pyruvate carboxylase

Question 35

Where in the body is pyruvate carboxylase high?

Answer 35

liver and nervous tissue