BMS07-1031 Energy Release from Fat

Question 1

Name 3 common fatty acids and how many C they have

Answer 1

Linoleic acid
Liolenic acid
Stearic acid
All have 18 and 0 2 and 3 double bonds

Question 2

Where do we break down triglycerides?

Answer 2

Adipose tissue

Question 3

Describe the breakdown of triglycerides

Answer 3

Triacylglycerol lipase removes a FA

DAG lipase removes a FA

MAG lipase removes a FA

Question 4

What 2 things activate lipase?

Answer 4

Adrenaline

Glucagon

Question 5

How and where do FA travel to?

Answer 5

Bound to albumin to enter the plasms

Question 6

Why do we want to make glycerol?

Answer 6

It is water soluble and can be taken up by all tissues to be used in glycolysis

Question 7

Why can glycerol be fed into glycolysis?

Answer 7

Its only 3C so can be easily changed into pyruvate

Question 8

How is glycerol used in glycolysis?

Answer 8

Converted to glucose in gluconeogenesis

Question 9

What are intermediates of FA metabolism?

Answer 9

CoA thioesters

Question 10

How are FA activated? Where does this occur?

Answer 10

Enzyme acyl-CoA synthetase
ATP used
CoASH added
To form fatty acyl-CoA in cytosol

Question 11

What do we do with the fatty acyl CoA?

Answer 11

Transported from the cytosol into the mitochondria by…

Added to carnitine to form CoA and a carnitine molecule using the protein carnitine palmitoyl transferase 1

Question 12

What happens after this?

Answer 12

Carnitine palmitoyl transferase 2 returns everything to its original form

Question 13

Describe reaction 1

Answer 13

Fatty acyl CoA has 2 H removed by FAD using the enzyme acyl-CoA dehydrogenase to form enoyl-CoA hydratase

Question 14

Describe reaction 2

Answer 14

Enoyl-CoA hydratase is used to convert enoyl-CoA to hydroxyacyl CoA by adding water

Question 15

Describe reaction 3

Answer 15

Hydroxyacyl CoA is converted to beta ketoacyl CoA by adding 2H to NAD and using the enzyme hydroxyacyl CoA dehydrogenase

Question 16

Describe reaction 4

Answer 16

Beta ketoacyl CoA is converted to fatty acyl CoA and acetyl CoA using the enzyme beta ketoacyl CoA tholase and adding CoA SH

Question 17

How many C will have been lost after the process?

Answer 17

2

Question 18

How do we metabolise odd numbered fats?

Answer 18

A carbon dioxide is added using ATP and propionyl CoA carboxylase enzyme

Methylmalonyl CoA mutase then converts this to succinyl CoA

Question 19

When does ketogenesis occur?

Answer 19

When fat is the main source of energy e.g. in starvation and type 1 diabetes

Question 20

What is converted to ketone bodies?

Answer 20

Acetyl coA

Question 21

How are ketone bodies used?

Answer 21

Converted back to TCA intermediates like acetyl CoA and succinate

Question 22

Why cant the liver use keton bodies?

Answer 22

It doesn’t have the enzymes to convert it to anything else so it would be pointless