Lipids

Question 1

What are the functions of lipids?

Answer 1

Stored forms of energy
Structural element of cell membranes
Vitamins A, D,E and K
Hormones
Enzyme cofactors
Signalling Molecules

Question 2

Name 5 classes of lipids.

Answer 2

Fatty Acids
Triglycerides
Phospholipids
Glycolipid
Steroids

Question 3

What is the main dietary lipid?

Answer 3

Triglyceride/ Triacylglycerol

Question 4

How are fatty acids transported in the blood?

Answer 4

As lipoproteins with the plasma protein, albumin

Question 5

What are the four classes of lipoproteins?

Answer 5

Chylomicrons
HDL
LDL
VLDL

Question 6

What is the process by which fatty acids are degraded?

Answer 6

Beta Oxidation

Question 7

What is the function of B oxidation?

Answer 7

To produce Acetyl CoA, and reduced NAD and FAD

Question 8

Where does B oxidation occur?

Answer 8

Cytosol and Mitochondrial Matrix

Question 9

What are the three stages of B oxidation?

Answer 9

Activation
Transport
Degradation

Question 10

Describe what happens in the Activation stage of B oxidation.

Answer 10

Fatty Acids are activated to Fatty acyl CoA

Question 11

Describe what happens in the Transport stage of B oxidation.

Answer 11

Carnitine shuttle (Carnitine palmityl transferase II) is used to transport activated long chain fatty acids from the cytoplasm into the inner mitochondrial matrix.

Question 12

Describe what happens in the Degradation stage of B oxidation.

Answer 12

Dehydrogenation- Oxidation of FAD to FADH2
Hydration
Dehydrogenation - Oxidation of NAD to NADH
Thiolysis- Produces Acetyl CoA for Citric Acid cycle

Question 13

What inhibits the action of the carnitine shuttle?

Answer 13

Malonyl CoA (Used to make fatty acids and so prevents fatty acid synthesis and degradation occurring simultaneously)

Question 14

What happens to excess Acetyl CoA from fatty acid degradation?

Answer 14

Used in ketogenesis to create ketone bodies.

Question 15

What is the function of ketone bodies?

Answer 15

Used as an energy store for the brain and skeletal muscle tissue in times of starvation

Question 16

Where do the fatty acids in our body come from?

Answer 16

Either our diet or produced using excess carbohydrates or protein components from our diet.

Question 17

Where does fatty acid synthesis occur?

Answer 17

In the cytosol of cells in the :
Liver
Lactating Mammary glands
Adipose tissue

Question 18

How is acetyl CoA transported out of the mitochondria for fatty acid synthesis?

Answer 18

Using the Citrate shuttle

Question 19

What is the carrier protein for fatty acid synthesis?

Answer 19

Acyl Carrier Protein (ACP)

Question 20

What is the carrier protein for fatty acid degradation?

Answer 20

CoA

Question 21

What is the function of cholesterol?

Answer 21

Component of cell membranes

The starting material for the synthesis of steroid hormones- chemical messengers within the body.