Cell metabolism 2

Question 1

How are fatty acids stored

Answer 1

as triacylglycerols

Question 2

Why are fatty acids an ideal storage molecule

Answer 2

reduced and anhydrous

Question 3

Where is acetyl CoA produced

Answer 3

in the mitochondrion

Question 4

What are the 3 sources of fat

Answer 4

1) diet
2) de novo synthesis by liver
3) storage deposits in adipose

Question 5

Where are bile salts made and stored

Answer 5

liver and gallbladder

Question 6

What about bile salts can solublise fats

Answer 6

is hydrophilic and hydrophobic

Question 7

What does a lack of bile salts lead to

Answer 7

steatorrhea - fat passes through gut undigested

Question 8

How does orlistat work

Answer 8

inhibitor of gastric and pancreatic lipases

Question 9

By how much does orlistat reduce fat absorption

Answer 9

30%

Question 10

for how long is orlistat effective in treating obesity

Answer 10

for 2 years

Question 11

What are the side effects of orlistat

Answer 11

increased flatus
increased desire to defecate
steatorrhea
abdominal pain

Question 12

From where do chylomicrons acquire apoproteins

Answer 12

HDL ( high density lipoproteins)

Question 13

how are digested dietary products absorbed

Answer 13

by enterocytes that line the border of the small intestine

Question 14

What happens to triglycerides before incorporated into chylomicrons

Answer 14

synthesized by enzymes

Question 15

From where to where do chylomicrons travel

Answer 15

lacteals of the intestine to the thoracic duct to the left subclavian vein

Question 16

Where are lipoprotein lipases located

Answer 16

endothelial cells of adipose, skeletal and heart tissue

Question 17

what happens to fatty acids and glycerol when there are high levels of glucagon

Answer 17

fatty acids undergo beta oxidation

glycerol transported to liver to undergo gluconeogenesis

Question 18

What do lipoprotein lipases recognise

Answer 18

apoprotein

Question 19

What does the phospholipid monolayer surround

Answer 19

a core of cholesterol esters and triacyclglycerols

Question 20

What does the esterification of cholesterol do

Answer 20

makes it even more hydrophobic

Question 21

Where are cholesterol esters synthesized

Answer 21

plasma

Question 22

what are the reactants in the esterification of cholesterol esters

Answer 22

cholesterol and phosphatidyl choline

Question 23

What is the enzyme that catalyses the formation of cholesterol esters

Answer 23

lecithin: cholesterol acyltransferase

Question 24

What can LDLs be taken up by

Answer 24

macrophages or liver

Question 25

describe the life cycle of a VLDL

Answer 25

VLDL delivers fatty acids and glycerol to adipose tissue
Becomes a lipid dependent remnant.
It transfers apoproteins to HDL to become a IDL
It gains cholesterol esters from HDL
It becomes a LDL
The LDL is taken up by macrophages (causing atherosclerosis) or by the liver

Question 26

Why are HDLs called ‘good cholesterol’

Answer 26

take cholesterol from the periphery back to the liver for regeneration of bile salts or disposed of.
Lowers total serum cholesterol

Question 27

Why are LDLs called ‘bad cholesterol’

Answer 27

prolonged elevation leads to atherosclerosis

Question 28

why are LDLs called low density

Answer 28

more than 40% of weight made up of cholesterol esters

Question 29

What is the 1st step needed for the beta oxidation of fatty acids

Answer 29

fatty acid needs to be made into acyl CoA
done by acyl synthetase
ATP hydrolysed to AMP

Question 30

Describe how the carnitine shuttle works

Answer 30

Acyl CoA transfers Acyl group to carnitine in the presence of carnitine acyl transferase 1 (CAT1)
Acyl carnitine is then transferred into the cytoplasm of the cell by translocase
Acyl Carnitine reacts with CoA to form Acyl CoA in the presecence of carnitine acyl transferase 2 (CAT 2)