Bob's 6

Question 1

What classes of lipids are there?

Answer 1

Fatty acid derivatives (triglycerides)

Hydroxy-methyl-glutamic acid derivatives (ketone bodies and cholesterol

Vitamins (A,d,e,k)

Question 2

Energy storage in obesity

Answer 2

Almost all stored as triglycerols (fats) very hard to lose

Question 3

Where are fatty acids metabolised?

Answer 3

Not cells without mitochondria like RBC’s and not the brain as cannot pass barrier

Question 4

How is fat mobilised?

Answer 4

Insulin= triacylglycerol not mobilised

Glucagon= triacylglycerol mobilised

Question 5

How is triacylglycerol metabolised?

Answer 5

Hydrolysed by pancreatic lipases to glycerol and fatty acids. Then recombined in small intestine and transported by lipoproteins (chylomicrons) to adipose and consumer tissues

Question 6

How does the triglyceride/ fatty acid cycle work in glucose?

Answer 6

If extracellular glucose is low then fatty acids and glycerol will leave the cycle and be released by adipose tissue

Question 7

Where do triacylglyerides join metabolism?

Answer 7

Glycerol joins before pyruvate and fatty acids are joined to acetyl CoA

Question 8

How are fatty acids metabolised?

Answer 8

ATP spent to link them to CoA to form fatty acyl CoA using fatty acyl CoA synthase

Transported across inner mitochondrial membrane using carnitine shuttle

cycles through oxidative reactions where C2 removed each time

Beta oxidation is another name for it. Products go to Krebs cycle or electron transport chain

Question 9

Does fat or glucose give more energy?

Answer 9

Fat

Question 10

Key fatty acid metabolism points?

Answer 10

Occurs in most tissues and WBC’s but not brain or RBC’s.

Produces no ATP but intermediates used in electron transport chain and Krebs cycle

Will not occur in absence of oxygen

Cycle of reactions with 2C removed with each one

Question 11

Where is glycerol metabolised?

Answer 11

In the liver

Question 12

Role of acetyl coA in metabolism

Answer 12

Many pathway merge with it

Can be used to make triglycerols and phospholipids from fatty acids. Ketone bodies and cholesterol from HMG

Question 13

What are the three ketone bodies in the body?

Answer 13

Acetoacetate

Acetone

B-hydroxybutyrate

Ketone body levels rise with starvation

Less than 1 mM normally

2-10 in starvation

Greater than 10 in ketosis (diabetes)

Question 14

How is ketone body production controlled in the liver?

Answer 14

High NADH will cause a build up of citrate which will cause acetyl coA to form ketone bodies instead of going through Krebs cycle.

Question 15

How is acetyl CoA made?

Answer 15

Through acetoacetate entering the Krebs cycle.

Question 16

How does being fed or starved affect ketone body and cholesterol production?

Answer 16

When fed (insulin) make cholesterol when starved (glucagon)make ketone bodies

Question 17

When are most ketone bodies made?

Answer 17

In starvation. Low sugar glucose so low insulin. HMG CoA reductase inhibited so ketone bodies formed instead of cholesterol.

Spares glucose for use by the brain

Question 18

How can glucose be made for the brain during starvation?

Answer 18

From proteins through gluconeogenesis

Question 19

How does ketoacidosis come about in diabetes?

Answer 19

Low insulin so body tricked into thinking its starving. HMG CoA reductase inhibited and ketone bodies are made. Two of these ketone bodies are acidic= affects blood pH

Question 20

How could you potentially detect ketoacidosis?

Answer 20

Smell of acetone on breath (nail varnish remover)