biochemistry - lipid catabolism

Question 1

increase in number of adipocytes and the concentration of fat in adipocytes is due to

Answer 1

increased fat intake without appropriate energy expenditure

obesity

Question 2

characteristics of triglycerides 4

Answer 2

main energy storage in adipose tissue
compact
hydrophobic
high energy yield/g

Question 3

strucure of triglycerides

Answer 3

glycerol + 3 fatty acids

Question 4

3 main products of fat digestion

Answer 4

glycerol
fatty acids
monoglycerides

Question 5

short and medium length fatty acids are absorbed and enter portal blood, what happens to longer chains

Answer 5

longer FA’s (and monoglycerides) are re-synthesised to triglycerides

Question 6

chylomicrons coat the triglycerides (layer of protein, phospholipid and cholesterol) what does this allow

Answer 6

transportation of triglyceride from intestines to other areas

Question 7

how are chylomicrons transported to other areas

Answer 7

enter lymph then blood stream

Question 8

what happens to chylomicrons in muscle and adipose tissue

Answer 8

cleaved by lipoproteins, releasing free fatty acids

Question 9

what happens to the free fatty acids released from chylomcrons in muscle and adipose tissue

Answer 9

depends on availability
muscle - oxidised, provide energy
adipose - resynthesised in triacyglycerols (storage)

Question 10

lipolysis

Answer 10

breakdown of lipids

Question 11

effect of cleavage of lipids by hormone sensitive lipases

Answer 11

releases free fatty acids and glycerol

when energy required

Question 12

before fatty acids can be oxidised (generates energy0 what do they have to be converted to? where does this occur? name of end product

Answer 12

CoA derivatives
ribsome
acetyl-CoA

Question 13

acyl-carnitine transporter in the inner membrane facilitates (2)

Answer 13

antiport of acyl-carnitine into mitochondrion, and carnitine out

Question 14

which enzyme activates breakdown of glycerol

Answer 14

glycerol kinase

converts to glycerol-3-phosphate

Question 15

where are ketones formed, from what

Answer 15

in liver mitochondria

acetyl-CoA in beta-oxidation

Question 16

purpose of ketone bodies

Answer 16

important molecules of energy metabolism for heart muscle and renal cortex

Question 17

what happens to ketone when in heart muscle and renal cortex

Answer 17

converted back to acetyl-CoA and enters TCA cycle

Question 18

during starvation or diabetes, high levels of ketone bodies are observed, what does this cause

Answer 18

since ketones are moderate acids, leads to severe acidosis which impairs tissue function