Lecture 34

Question 1

What is PDH tightly regulates by?

Answer 1

Reversible phosphorylation

Question 2

What does the active and inactive form of PDH feature?

Answer 2

The inactive PDH is phosphorylated

Question 3

What is PDH Phosphatase activated by?

Answer 3

Ca2+ in muscle

Question 4

What does PDH Phosphatase do?

Answer 4

Dephosphorylates PDH turning it to its active form

Question 5

What does PDH kinase do?

Answer 5

It phosphorylates PDH inactivating it

Question 6

What are the products of the PDH reaction?

Answer 6

Acetyl-CoA and NADH

Question 7

What suppresses PDH by activating PDH kinase?

Answer 7

Acetyl-CoA and NADH

Question 8

What inactivates PDH kinase that would normally go on to create inactive PDH?

Answer 8

ADP, Pyruvate and NAD+ which are all substrates of PDH

Question 9

How do substrates and products effect PDH?

Answer 9

• NADH and acetyl-CoA are products and inhibit the complex

* NAD+ and HS-CoA are substrates and activate the complex

Question 10

Which compounds are used to synthesize ATP using phosphate transfer reactions?

Answer 10

• 1,3-bisphosphoglycerate
• Phosphoenolpyruvate
• Phosphocreatine

Question 11

What is Pyruvate kinase regulated by and how?

Answer 11

F-1,6-BP and allosteric activation

Question 12

How is PFK-1 regulated by PEP?

Answer 12

By feedback inhibition

Question 13

How is Pyruvate Kinase regulated by ATP?

Answer 13

Through allosteric inactivation

Question 14

How is Hexokinase regulated by G-6-P?

Answer 14

Through feedback inhibition

Question 15

How is NADH reoxidized during catabolism?

Answer 15

• NADH is reoxidized via the electron transport chain

* NADH is reoxidized via participating in certain reduction reactions

Question 16

What does the citric acid cycle start off with?

Answer 16

Acetyl-CoA

Question 17

What kind of process is the Citric Acid Cycle?

Answer 17

An aerobic process

Question 18

What is the purpose of Aerobic Catabolism?

Answer 18

To capture energy in biological fuel molecules and use it to make ATP

Question 19

Why can acetyl-CoA sometimes be described as a two-carbon molecule?

Answer 19

Because there are two carbons in the acetyl portion

Question 20

What is the next molecule produced from acetyl CoA in the citric acid cycle?

Answer 20

Citrate

Question 21

What are the sources of Acetyl-CoA?

Answer 21

It comes from many sources like carbohydrate, fatty acid and amino acid catabolism

Question 22

What does Acetyl-CoA condense to make in the citric acid cycle?

Answer 22

It condenses with oxaloacetate (4C) to make citrate (6C)

Question 23

How many carbons are oxidized to make CO2?

Answer 23

Two carbons

Question 24

How many carboxylates does citrate have?

Answer 24

Three

Question 25

What happens every time carbon dioxide is produced in the CAC?

Answer 25

A carbon has been fully oxidized as far as it can go

Question 26

Why is the CAC a cyclic process?

Answer 26

Because oxaloacetate is consumed but also regenerated

Question 27

What high energy molecules are produced in the CAC?

Answer 27

* 3 NADH * 1 FADH2/QH2 * 1 GTP

Question 28

Where does the CAC occur?

Answer 28

In the mitochondrial matrix

Question 29

What does the CAC do?

Answer 29

Oxidizes acetyl-CoA to CO2

Question 30

What high energy products does the CAC produce?

Answer 30

* 3 NADH * FADH2/QH2 * GTP (NTP)

Question 31

Why is the CAC Aerobic?

Answer 31

Because O2 reduction is required to reoxidize NADH, FADH2

Question 32

What is Acetyl-CoA generated by?

Answer 32

Metabolism of many compounds •Fats •Carbohydrates •Proteins

Question 33

Is the CAC anabolic or catabolic?

Answer 33

It is amphibolic

Question 34

What are the four important enzymes in the CAC that catalyze irreversible reactions?

Answer 34

* Citrate synthase * Isocitrate dehydrogenase * alpha-ketoglutarate dehydrogenase complex * Succinate dehydrogenase complex

Question 35

What are the four important enzymes in the CAC that catalyze irreversible reactions?

Answer 35

* Citrate synthase * Isocitrate dehydrogenase * alpha-ketoglutarate dehydrogenase complex * Succinate dehydrogenase complex

Question 36

What is Succinate dehydrogenase part of?

Answer 36

Complex II

Question 37

What is different about Succinate dehydrogenase?

Answer 37

It is not in the matrix like the other enzymes that participate in the CAC

Question 38

What does Citrate Synthase catalyze?

Answer 38

The conversion of acetyl-CoA and Oxaloacetate and water into HS-CoA + H+ and Citrate

Question 39

What kind of reaction does citrate synthase catalyze?

Answer 39

An irreversible isomerization

Question 40

Is citrate synthase regulated?

Answer 40

No, not under physiological condition

Question 41

How many carbons is citrate?

Answer 41

6 Carbons

Question 42

What happens to the citrate produced by Citrate synthase?

Answer 42

It undergoes an isomerization where the hydroxyl group in citrate is moved to the adjacent carbon to form a carbonyl and forms isocitrate

Question 43

What kind of reaction is the conversion of isocitrate to alpha ketoglutarate?

Answer 43

An oxidative decarboxylation

Question 44

What enzyme converts Isocitrate to alpha-ketoglutarate?

Answer 44

Isocitrate dehydrogenase

Question 45

Is the conversion of Isocitrate to alpha-ketoglutarate reversible?

Answer 45

No

Question 46

What are the other products besides alpha-ketoglutarate in the CAC created by isocitrate dehydrogenase?

Answer 46

NADH and CO2

Question 47

What can alpha-ketoglutarate be converted to?

Answer 47

Glutamate