Lipids 2 Flashcards Preview

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Flashcards in Lipids 2 Deck (27)
1

In the beta oxidation pathway, how many fatty acid carbons does it break down at a time?

2

2

What are the products of beta oxidation?

Acetyl CoA, NADH, and FADH2 all sources of energy for ATP

3

Where does beta oxidation occur?

In the mitochondrial matrix

4

What does FA released from an adipocyte bind to?

Albumen

5

What are the 3 stages of beta oxidation?

Activation, transport and degradation

6

How is the fatty acid activated?

It is involved in a reaction using ATP to form fatty acyl co a in the CYTOPLASM (of the target tissue)

7

How does the fatty acyl co a cross the mitochondrial walls?

Fatty acyl co a diffuses across the first membrane. The carnitine shuttle is responsible for the movement of the fatty acyl co a across the second membrane- Co a component of the molecule is removed, remaining molecule then binds to carnitine and passes over the membrane with help from translocase. Carnitine is removed and fatty acyl co a is reformed

8

What is the effect of malonyl co a?

Inhibits the transferase enzymes, preventing further degradation of the fatty acid. Malonyl is needed for FA synthesis - therefore prevent the synthesis and degradation happening at the same time.

9

What is the effect of carnitine fatty acyl tranferase or carnitine palmitoyl transferase deficiency?

No beta oxidation
Hypoglycemia

10

What are the steps of degradation?

Dehydrogenation - produces FADH2
Hydration - Requires H20
Dehydrogenation- To produce NADH
Thyolysis- Cleaved to produce acetyl co a

11

What is the precursor of FADH2 and NADH

FADH2 = FAD
NADH = NAD+

12

What happens to acetyl co a produced?

Joins TCA cycle (citric acid cycle)

13

What carbon products are produced after every beta oxidation cycle?

A carbon species two carbons shorter than the original + acetyl co a

14

How much ATP does each of the following molecules give / use?
FADH2
NADH
Acetyl Co A

FADH2 = 2 ATP
NADH = 3 ATP
Acetyl Co a = 12 ATP

15

Where does a preliminary beta oxidation of very long fatty acids take place?

Peroxisomes

16

Why is the first step (dehydrogenation) less energy efficient?

No FADH2 is produced

17

What happens to the FA linked to the carnitine?

Diffuses from peroxisome to mitochondria for further oxidation

18

What happens to acetyl co a levels during fasting / starvation?

Liver flooded with acetyl co a

19

What is the effect of high acetyl co a levels on pyruvate dehydrogenase?

Pyruvate dehydrogenase is inhibited reducing further acetyl co a formation?

20

What is the effect of high acetyl co a levels on pyruvate carboxylase?

Activates pyruvate carboxylase and therefore increases the oxaloacetate present

21

What does the amount of ketogenesis depend on?

The amount of acetyl co a, excess is converted into ketone bodies

22

What muscles use ketone bodies as an energy source?

The skeletal muscles, and the cardiac muscles

23

What important organ can ketone bodies also provide energy for?

The brain

24

Where are ketone bodies formed?

The liver, although the liver cannot actually use them!

25

How are ketone bodies transported from the liver?

In the blood to other tissues, they are soluble and do not need albumen or lipoprotein

26

What can lead to very high levels of ketone bodies in the blood?

Starvation or uncontrolled diabetes

27

What can result from a higher build to use ratio of etone bodies?

Ketonemia, ketonuria and acidosis
fruity breath odour due to acetone