Lecture 42: Fatty Acid Oxidation Flashcards

1
Q

Under what physiological conditions does FAO become the predominant source of energy?

A
  1. heart muscle
  2. extended periods of exercise
  3. periods of starvation
  4. diabetic patients in whom glucose
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2
Q

Describe the difference between long distance versus short distance runners.

A

Long distance: lean because of oxidation of fatty acids

short distance: muscular and break down glycogen

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3
Q

List some problems that fatty acid oxidation defects may be involved with.

A
  1. symptoms of Reyes-like syndrome
  2. cardiomyopathy
  3. hypotonia
  4. hypoglycemia
  5. developmental delay
  6. SIDS
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4
Q

Release of fatty acids is done through ______.

A

hormonal action

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5
Q

Triacylglycerol lipase functions only on triacylglycerol making it into what compound?

A

diacylglycerol

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6
Q

T/ F: Triacylglycerol lipase is active when dephosphorylated.

A

False. The triacylglycerol is phosphorylated when activated.

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7
Q

What does insulin do to lipid synthesis?

A

It enhances lipid synthesis by increasing the synthesis of glycolytic enzymes and enzymes that are involved in fatty acid synthesis (acyl CoA).

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8
Q

What are lipolysis inducing hormones?

A

Epinephrine
glucagon
adrenocorticotropic hormones

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9
Q

Fatty acids are activated by which enzyme?

A

Acyl CoA syntthetase

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10
Q

Where is Acyl CoA present?

A
  1. cytosol

2. outer mitochondrial membrane

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11
Q

T/F: Acyl CoA can travel through the outer mitochondrial membrane but not the inner mitochondrial membrane.

A

True.

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12
Q

Which enzyme is used to make Acyl carnitine, which can travel through the inner mitochondrial membrane?

A

carnitine acyltransferase I (it is the rate limiting enzyme)

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13
Q

Acyl carnitine is coverted into acyl CoA by which enzyme?

A

Carnitine acyltransferase II

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14
Q

What does carnitine acylcaritine translocase do?

A

It transports Acyl carnitine through the inner mitochondrial membrane.

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15
Q

What are three enzymes that are involved in the first step of beta oxidation pathway?

A

LCAD
MCAD
SCAD

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16
Q

What is the ultimate purpose of the beta oxidation pathway?

A

oxidize beta carbon

remove 2 carbons in the form of acetyl CoA

2 carbon shorter acyl CoA

17
Q

Which enzyme do SIDS kids have a deficiency in?

A

MCAD

18
Q

Which do you get more energy from: unsaturated or saturated fatty acids?

A

saturated releases more energy because no double bonds so FADH2 produced every cycle

19
Q

What is the equation used to know the number of acetyl CoA from a fatty acid?

A

no. of compounds/2

20
Q

How do you find the no. of FADH2 and NADH?

A

No of C-2/2

remember: for FADH2, subtract one for every double bond in the original compound

21
Q

When you have odd numbered carbon fatty acids, what kind of CoA is formed?

A

Propionyl CoA

22
Q

What happens to propionyl CoA?

A

It becomes succinyl CoA and enters the TCA cycle

23
Q

Why do you form ketone bodies?

A

They are formed due to excessive oxidation of fatty acids and it produces a lot of acetyl CoA. It is caused by diabetes/ periods of starvation.

24
Q

What are the two (or three) ketone bodies?

A

Acetoacetate
D- beta- hydroxybutyrate
(acetone)

25
Q

What is a ketone body?

A

It is a substance that is used to produce energy

26
Q

Where in the body are ketone bodies used?

A

They can be used by the heart, brain and muscle for energy.

27
Q

T/F: The concentration of ketone bodies in the plasma should be zero normally.

A

False. The concentration of ketone bodies in the plasma will never be zero. It is present in low concentrations and is elevated when starving/ have diabetes.

28
Q

CPT1 (Carnitine palmoitoyl transferase I) is another name for which enzyme?

A

Carnitine acyltransferase I

29
Q

What compound inhibits carnitine acyltransferase I or carnitine palmoitoyl transferase I?

A

malonyl CoA which is a product of fatty acid synthesis

30
Q

Which hormones regulate fatty acid oxidation?

A

Glucagon (increae)
Epinepherine (increase)
insulin (decrease)

these affect triacyl glycerol (aka hormone sensitive lipase)

31
Q

How can you correct carnitine deficiency?

A

give carnitine in the diet

32
Q

How is fattyacyl CoA synthetase deficiency or mutations in acyl carnitine- carnitine mutations corrected?

A

It is corrected by giving C8, C10 fatty acids because they are free fatty acids that do not need to be converted to acyl carnitine to get through the inner mitochondrial membrane.