ATP synthesis

Question 1

Three conformations of beta subunits

Answer 1

1. Beta ATP-binds ATP (tightly bound)
2. Beta ADP-binds ADP and Pi (loosely bound)
3. Beta empty-low affinity for ATP (very loosely bound)
   * you will never have two beta units in the same conformation at the same time*

Question 2

Do alpha and beta subunits rotate?

Answer 2

No; they make conformational changes as the gamma subunit rotates

Question 3

Malate-aspartate shuttle

Answer 3

2.5 ATP/NADH

transports to liver, kidney, and heart

Question 4

Glycerol-3-phosphate shuttle

Answer 4

1.5 ATP/NADH

transports to brain and skeletal muscle

Question 5

Adenine Nucleotide and Phosphate translocases

Answer 5

membrane transporter that moved charged ATP, ADP, and Pi molecules across the mitochondrial membrane

Question 6

How many protons are pumped out of the matrix through the electron transport chain? How many re-enter through ATP synthesis?

Answer 6

Through Complex I: 10
Through Complex II: 6
Re-enter: 4 (3 used by beta subunits, 1 used by a phosphate translocase)

Question 7

1 NADH= ? ATP

Answer 7

2.5 ATP

Question 8

1 FADH2= ? ATP

Answer 8

1.5

Question 9

Agents that interfere with oxidative phosphorylation

Answer 9

Rotenone Amytal: prevents electron transport from Complex I to
Ubiquinone
CN- and CO: inhibits cyt oxidase of Complex IV

Question 10

Thermogenin

Answer 10

Uncoupling protein used to produce heat instead of ATP in brown fat. Protons bypass the ATP synthase protein using the uncoupling protein and release the energy as heat

Question 11

4 lipid classes

Answer 11

1. triacylglycerols
2. cholesterols
3. phospholipids
4. fatty acids

Question 12

Alpha Carbon in a fatty acid

Answer 12

Carbon next to the carboxylic acid carbon

Question 13

Energy per 1g of fatty acid

Answer 13

37 kJ/g

~100 ATP

Question 14

Lipases

Answer 14

Cleave ester bonds in triacylglycerol to produce a glycerol backbone and 3 fatty acid components

Question 15

Pancreatic lipase

Answer 15

Only releases two fatty acids from a triacylglycerol

Question 16

Lipolysis

Answer 16

Breakdown of triacylglycerol in lipoproteins

Question 17

Lipoprotein Lipase and Hormone-Sensitive Lipase

Answer 17

Cleave all three fatty acids

Question 18

What happens to fatty acid components of a triacylglycerol? The glycerol backbone?

Answer 18

Fatty Acids: oxidized for energy (occurs in mitochondria)

Glycerol: converted to glucose

Question 19

Two requirements for fatty acids to be oxidized

Answer 19

1. Activated (bound to CoA; outer mitochondrial membrane)

2. Transported (carnitine shuttle; inner mitochondrial membrane)

Question 20

What stops the activation of fatty acid from being a reversible reaction?

Answer 20

The use of pyrophosphatase that converts pyrophosphate to two inorganic phosphates

Question 21

Rate limiting step of fatty acid oxidation

Answer 21

fatty acid transport into the mitochondrion

Question 22

3 Steps to produce ATP from fatty acids

Answer 22

1. beta oxidation- degradation of fatty acids (acyl CoA), 2 carbons at a time, to produce acetyl CoA
2. Acetyl CoA from beta oxidation are oxidized to carbon dioxide (TCA cycle)
3. Production of ATP (oxidative phosphorylation)

Question 23

4 steps of beta oxidation

Answer 23

1. oxidation (acyl CoA dehydrogenase: introduces trans double bond, uses FAD+)
2. hydration (Enoyl CoA hydratase)
3. oxidation (beta dehydroxyacyl-CoA dehydrogenase, uses NAD+)
4. cleavage (thiolase: cleaves thioester bond)

Question 24

How many cycles are involved in the oxidation of palmatic acid?
What are the molecules produced?
How many ATP are produced?

Answer 24

7 cycles
Produces: 8 acetyl CoA, 7 FADH2, 7 NADH, 7 H+
Net production of 106 ATP

Question 25

What inhibits the oxidation of fatty acids?

Answer 25

Malonyl CoA

Question 26

What are the ketone bodies used when glucose is not available for the brain?

Answer 26

Acetoacetate and beta hydroxybutyrate

Question 27

What enzymes are used to convert acetoacetate into acetone and beta hydroxybutyrate?

Answer 27

Dehydrogenase enzyme forms beta hydroxybutyrate

Spontaneous decarboxylation forms acetone

Question 28

Where does the metabolism of ketone bodies take place?

Answer 28

Mitochondria (a lot like beta oxidation)

Question 29

Diabetic ketosis

Answer 29

Acidosis that results from an over production of mildly acidic ketone bodies due to diabetes

Question 30

Conformational changes to beta subunits when gamma rotates

Answer 30

1. Beta empty -> Beta ADP + Pi
2. Beta ADP + Pi -> Beta ATP
3. Beta ATP -> Beta empty