Lecture 26 - Fatty acids as a fuel molecule #2

Question 1

Do adipose tissues make lipoproteins?

Answer 1

NO

Question 2

What does adipose lipase do?

Answer 2

cleaves TAGs to give
three FFAs and glycerol

Question 3

Are free fatty acids polar or non-polar?

Answer 3

non-polar

Question 4

Where can fatty acids come from?

Answer 4

• diet or the liver
• storage in adipose tissue

Question 5

How is the delivery of fatty acids to tissues?

Answer 5

1. Adipose lipase makes FFA + Glycerol by cleaving TAG
2. FFA passively travel in blood
3. FFA bind albumin
4. Transported to tissues passively

Question 6

When are fatty acids activated?

Answer 6

before B-oxidation

Question 7

When does fatty acid activation occur before or after entering the mitochondria?

Answer 7

Before

Question 8

How are fatty acids activated?

Answer 8

By the attachment of CoA to make fatty acyl-CoA

Question 9

What energy is required to CoA?

Answer 9

hydrolysis of ATP to AMP (energy equivalent of 2 ATP)

Question 10

Oxidation of fatty acids occurs in the?

Answer 10

mitochondrial matrix

Question 11

Movement between the cytosol and matrix
requires?

Answer 11

two membranes to be crossed

Question 12

How are fatty acids transported to the mitochondrial matrix?

Answer 12

• The fatty acyl-CoA must pass through two membranes
• Outer membrane: uses fatty acyl-CoA carrier
• Inner membrane: requires the conversion to fatty acyl-carnitine

Question 13

The carnitine acyltransferase reaction?

Answer 13

• Exchanges CoA and carnitine on a fatty acid
• Reversible reaction

Question 14

Where does B-oxidation occur?

Answer 14

In mitochondrial matrix

Question 15

What fatty acids does B-oxidation use?

Answer 15

fatty acids with an even number of carbons that are saturated (no double bonds)

Question 16

Is ATP produced during B-oxidation?

Answer 16

No, ATP is not directly made in β-oxidation

Question 17

What is energy released during B-oxidation transfered to?

Answer 17

the coenzymes NAD and FAD

Question 18

What happens to the carbon chain during B-oxidation?

Answer 18

Is cut into two pieces

Question 19

What is the product of B-oxidation?

Answer 19

acetyl-CoA

Question 20

What happens to acetyl CoA?

Answer 20

is further oxidised in the citric acid cycle

Question 21

What are the 4 steps of B-oxidation?

Answer 21

1. Oxidation
2. Hydration
3. Oxidation
4. Cleavage

Question 22

What happens during the first reaction of B-oxidation (oxidation)?

Answer 22

Fatty acyl-CoA is oxidised forming a double bond, the 2x H atoms form FADH2 from FAD (FAD -> FADH2)

Question 23

What happens during the second reaction of B-oxidation (hydration)?

Answer 23

Fatty acyl-CoA is hydrated by the addition of H2O, this breaks the double bond and puts an OH on one carbon and H on the other

Question 24

What happens during the third reaction of B-oxidation (oxidation)?

Answer 24

Fatty acyl-CoA is oxidised, the O of the OH loses its hydrogen forming a double bond, and the carbon bonded to the O loses its hydrogen. (NAD+ -> NADH + H+)

Question 25

What is FAD derived from?

Answer 25

Riboflavin (vitamin
B2)

Question 26

What is FAD?

Answer 26

A coenzyme required by some
enzymes that catalyze redox
reactions (including fatty acid
oxidation, citric acid cycle)

Question 27

What does FAD stand for?

Answer 27

Flavin adenine dinucleotide

Question 28

Flavin coenzymes are ……
bound to the proteins with which they interact (flavoproteins)

Answer 28

tightly

Question 29

What type of reduction does FAD undergo?

Answer 29

a two-electron reduction
(accepts two reducing equivalents)

Question 30

What do the first three reactions of B-oxidation involve?

Answer 30

• rearrangement:
• energy captured (2 redox reactions)
• Overall alter chemistry around the bond for cleaving
  in reaction 4

Question 31

What occurs during reaction 4 (cleavage)?

Answer 31

is a cleavage between the ⍺
and β carbons

Question 32

What is released during reaction 4?

Answer 32

Acetyl-CoA

Question 33

What is added to the remaining carbon chain after the release of acetyl-CoA?

Answer 33

CoASH

Question 34

What happens to the remaining fatty acyl-CoA after completion of cycle?

Answer 34

After becoming 2 carbons shorter it re-enters the B-oxidation cycle

Question 35

What is released during one round of B-oxidation?

Answer 35

1 NADH + 1 FADH2 + 1 acetyl-CoA

Question 36

How do you calculate the number of rounds of B-oxidation a FFA can undergo?

Answer 36

no. of rounds = n(C)/2 - 1

Question 37

What are the products of 7 rounds of B-oxidation?

Answer 37

7 NADH, 7 FADH2 and 8 acetyl-CoA