MCM- Lipid Catabolism Flashcards Preview

Biochemistry > MCM- Lipid Catabolism > Flashcards

Flashcards in MCM- Lipid Catabolism Deck (54):
1

How many phases of fatty acid breakdown are there

2 phases

2

What is Phase 1 of Fatty Acid Breakdown

Transport of free fatty acids into the mitochondrial matrix

3

What is Phase 2 of Fatty Acid Breakdown

Beta-Oxidation

4

What shuttle transports free fatty acids into the mitochondrial matrix

Carnitine Shuttle

5

Two Sources of Fatty Acids

Dietary Fats and Stored Fats

6

Where does Fatty Acid Activation Occur

The Cytosol

7

What is bound to Fatty Acids in the cytosol

Albumin

8

What is Albumin's goal when bound to Fatty Acids

Keep it soluble

9

Once activated what is the form of the Fatty Acid

Fatty Acyl-CoA

10

Can Fatty acyl-CoA get into the Mitochondria

No; the outside membrane of the mitochondria is impermeable to Fatty Acyl-CoA

11

Why does Fatty Acid Activation need to occur

Because Fatty Acids bound with albumin are impermeable to the plasma membrane

12

What happens to Fatty Acyl-CoA to get into the inner membrane

Carnitine is added and CoA is detracted making Fatty Acyl-Carnitine

13

What happens to Fatty Acyl Carnitine once it is in the mitochondrial matrix of the mitochondria

Carnitine is removed and Fatty Acyl-CoA is remade

14

What happens to Fatty Acyl-CoA once it is remade in the Mitochondrial Matrix

Beta-Oxidation

15

Which Fatty Acids can diffuse into the Mitochondria

Short and Medium Chain

16

What is the rate limiting step of the Carnitine Shuttle

Carnitine Palmitoyltransferase-1; CPT1

17

What inhibits Carnitine Palmitoyltransferase-1

Malonyl-CoA

18

Where is the Carnitine Palmitoyltransferase-1 located

In the mitochondrial intermembrane space

19

What are the products of Beta Oxidation and where do they go

Acetyl-CoA; enters the TCA cycle
FADH2; delivers electrons to Ubiquinone of ETC
NADH; delivers electrons to Complex 1 of ETC

20

How many steps of Beta Oxidation are there

Four

21

What are the four steps of Beta Oxidation

1. Oxidation
2. Hydration
3. Oxidation
4. Thiolysis

22

What enzyme performs step 1 of Beta Oxidation

Acyl CoA Deydrogenase; Oxidate

23

What is the rate limiting step of Beta Oxidation

Acyl-CoA Deydrogenase (ACAD)

24

What are the four reactions of Beta Oxidation in order

1. Oxidation
2. Hydration
3. Oxidation
4. Thiolysis

25

What does Acyl CoA Dehydrogenase do

oxidizes the Beta and Alpha carbon to produce FADH2 and trans-enoyl-CoA

26

How many ATP does one mole of Palmitic Acid produce

Nets 106 ATP; 2 used in the activation of the Fatty Acid

27

What is the difference of odd numbered fatty acids vs. even number fatty acid Beta Oxidation

Odd numbered fatty acids are metabolized until a 3 C fatty acid (Propionyl-CoA). Propionyl-CoA is then converted through two different enzymes to Succinyl-CoA

28

What is the fate of Succinyl-CoA from the Beta Oxidation of Odd Numbered Fatty

It enters the TCA Cycle

29

What happens to Unsaturated Fatty Acids in Catabolism

Metabolized until unsaturation is reach then a REDUCTASE reduces the double bond and an ISOMERASE moves the disruptive bond

30

Where does breakdown Very Long Chain Fatty Acids

Peroxisome

31

What does beta oxidation in the peroxisome produce

H2O2; too much is toxic but the peroxisome needs H2O2 to function in immune system

32

What is the key enzyme in the Beta Oxidation of VLCFA

Acyl-CoA Oxidase

33

What does Acyl-CoA Oxidase in the peroxisome produce

FADH2; which is used to make H2O2. It does not go to the OX-PHOS pathway

34

Metabolic Defects in FA-Oxidation

Many enzymes can be defective

35

What happens when the enzymes that cleave Carnitine are defective; in catabolism

Carnitine will build up in the transmembrane space; leading to a carnitine deficiency since Fatty Acyl-Carntine cant diffuse into the matrix through the inner membrane and it can go back out but stops after the outter membrane

36

Most common Fatty Acid Enzyme Deficiency in Catabolism

Medium Chain Acyl-CoA Dehydrogenase

37

What happens when the Medium Chain Acyl-CoA Dehydrogenase is deficient

C8 Fatty Acid accumulates in the liver, poisonous, interferes with urea cycle, elevated levels of ammonia

38

How to treat an MCAD deficiency

Patients depend on glucose as an energy source; so dietary treat

39

When are Ketone Bodies Favored

When you are in a fasting/starving state

40

What happens when Ketosis is preferred

Excessive B-Oxidation of FA's leading to Increase of Acetyl-CoA; one of the by-products of B-Oxidation

41

What are the three ketone Bodies

1. Acetoacetate
2. B-Hydroxybutyrate
3. Acetone

42

What happens when Acetone is built up in the body

Acetone breath; sweet

43

What disease, if uncontrolled, leads to a build up of ketones leading to ketoacidosis

Diabetes

44

Where are Ketone Bodies produced

The mitochondrial matrix of hepatocytes

45

What are Ketone Bodies used for

Provide energy in peripheral tissues(muscles), the brain under fasting conditions, and kidneys

46

Energy Yield of 1 mole of Acetoacetate

____ ATP - 1 from activation of Acetoacetate

47

Energy Yield of 1 mole B-Hydroxybutyrate

_____ ATP - 1 from activation of Acetoacetate

48

Where do Beta-Hydroxybutyrate and Acetone stem from

Acetoacetate

49

What happens to Catabolism in the first few hours of fasting

gluconeogenesis

50

What happens to Catabolism after 1 day of fasting

Triacylglycerols are broken down to release FFA to undergo Beta-Oxidation

51

What happens to Catabolism after 3 days of fasting

Ketone bodies made in liver and proteins in the muscles are broken down

52

What happens to Catabolism after 1-2 weeks of starvation

brain switches to ketone bodies as major energy source

53

What happens to Catabolism after 2-3 months of starvation

Triacylglyercols depleted, protein main source of energy

54

Difference of Physiological ketosis vs. Pathological Ketoacidosis

Ketosis; mild to moderate increase in ketone bodies

Ketoacidosis; massive accumulation of ketone bodies, occurs when glucagon/insulin ratio is increased, favoring fatty acid breakdown. Glucagon too high because insulin isnt receptive. Breaksdown all TAG supply and switches to ketone bodies