Lecture 26 Flashcards

1
Q

What are the three places fatty acids can be delivered from for fuel?

A

From the diet, liver or storage in the adipose tissue

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2
Q

Why does the adipose tissue not make lipoproteins

A

Adipose lipase cleaves TAGs to give three FFAs and glycerol

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3
Q

Why can’t fatty acids be delivered independently in the blood?

A

They are hydrophobic, the blood is hydrophilic

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4
Q

How do fatty acids travel in the blood?

A

They bind to albumin

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5
Q

What is albumin-FFA

A

A polar protein in the blood that has lots of slide chains that create hydrophobic pockets for the FFA to sit in

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6
Q

How do FFAs travel in the polar cytosol of the cell?

A

Bound to the hydrophobic core of FABP, a polar protein

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7
Q

What must happen before beta-oxidation?

A

Fatty acid activation

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8
Q

When does fatty acid activation happen?

A

Before it enters the mitochondria

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9
Q

How are fatty acids activated?

A

Energy is used to add a CoA to the FFA from hydrolysis of ATP to AMP

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10
Q

What is a fatty acyl-CoA?

A

A carbon chain of any length

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11
Q

What is an acyl-CoA?

A

A carbon chain

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12
Q

What is an acetyl-CoA?

A

A two carbon chain

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13
Q

How do fatty acids cross the outer mitochondrial membrane?

A

Passively, through the fatty acyl-CoA carrier

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14
Q

How do fatty acids cross the inner mitochondrial membrane?

A

Through a carrier however, the fatty acyl-CoA requires the conversion to fatty acyl-carnitine

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15
Q

What occurs in the intermembrane space?

A

The carnitine acyltransferase reaction

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16
Q

What does the caritine acyltransferase reaction do?

A

Carnitine acyltransferase I enzyme removes fatty acyl-CoA and adds it to carnitine

17
Q

What happens after the fatty acyl-carnitine passes through the inner membrane?

A

Fatty acyl-carnitine is converted back to fatty acyl-CoA through the reverse reaction using carnitine acyltransferase II

18
Q

What is beta-oxidation?

A

The process by which the body breaks down fatty acids to produce energy

19
Q

Where does beta-oxidation occur?

A

In the mitochondrial matrix

20
Q

How is energy released in beta-oxidation?

A

It is released to carrier coenzymes NAD and FAD

21
Q

What is the product of beta-oxidation?

A

Acetyl-CoA

22
Q

What happens to acetyl-CoA after beta-oxidation?

A

It is further oxidised in the citric acid cycle

23
Q

What is FAD?

A

Flavin adenine dinucleotide, a coenzyme derived from vitamin B2

24
Q

How do flavin coenzymes bind to proteins?

A

Very tightly

25
Q

What is the common use for FAD?

A

To catalyse redox reactions

26
Q

What happens to FAD in redox reactions?

A

It undergoes a two electron reduction, accepting two reducing equivalents (H)

27
Q

What are the four reactions in beta-oxidation?

A

Oxidation, hydration, oxidation again and cleavage

28
Q

What happens in the first oxidation reaction in beta-oxidation?

A

1x H from each C (2x H total) are cleaved, oxidising the C-C bond to a C=C bond. FAD+ accepts both H to become FADH2

29
Q

What happens in the hydration reaction in beta-oxidation?

A

C=C is hydrated to form OH-C-C

30
Q

What happens in the second oxidation reaction in beta-oxidation?

A

2x H, one from the OH and one from C-beta are removed, oxidising the compound and forming a O=C bond. NADH accepts one H to become NADH2

31
Q

What happens in the cleavage reaction in beta-oxidation?

A

Acetyl-CoA is released as part of the C-alpha chain. The energy released while breaking the C-C bond is used to add a CoASH to beta chain forming the same fatty acyl-CoA, with two less carbons

32
Q

What are the products of beta-oxidation?

A

If 7 rounds = 7 NADH, 7 FADH2, 8 acetyl-CoA + some heat

33
Q

What is the equation to determine no. rounds in beta-oxidation?

A

No. rounds = n(C)/2-1

34
Q

Why is some heat released in beta-oxidation?

A

Reaction is not 100% efficient

35
Q

What is NAD derived from?

A

Vitamin B3

36
Q

What is FAD derived from?

A

Vitamin B2

37
Q

What is coenzyme A derived from?

A

Vitamin B5