Biochemistry

Question 1

what is glycogenesis

Answer 1

formation of glycogen

Question 2

is glycogenesis, glucose is broken down to __ by __

Answer 2

glucose-6-phosphate by hexokinase

Question 3

in glycogenesis, G6P is broken down to __ by __

Answer 3

G1P by phophoglucomutase

Question 4

in glycogenesis, G1P is broken down to __ by __

Answer 4

UDP-glucose by UDP-glucose phosphorylase

Question 5

what converts UDP-glucose into glycogen

Answer 5

glycogen synthase

Question 6

glycogen synthase can form bonds what type of bonds in which direction

Answer 6

alpha-1,4 glycosidic

in straight chains only

Question 7

what type of bonds are made for branches of glucose molecules

Answer 7

alpha-1,6 glycosidic

Question 8

what is glycogenin

Answer 8

glucose primer required for glycogenesis

Question 9

what is glycogenolysis

Answer 9

breakdown of glycogen

Question 10

what inhibits and what promotes glycogenesis

Answer 10

insulin promotes

glycogen inhibits

Question 11

where does glycogenolysis mainly occur

Answer 11

liver

Question 12

___ is converted to glucose in the liver by __

Answer 12

G6P

by glycogen phosphorylase

Question 13

the G6P that isnt phosphorylated in the skeletal muscles does what?

Answer 13

transferred to TCA and glycolysis

Question 14

what is gluconeogenesis

Answer 14

formation of glucose from either lactate, amino acids or glycerol

Question 15

which type of amino acids can produce glucose by gluconeogenesis

Answer 15

glucogenic amino acids

Question 16

describe the Cori cycle

Answer 16

muscles produce lactate from fermentation, this lactate is transferred to the liver for gluconeogenesis making glucose which is then returned to skeletal muscles. Shifts metabolic burden to other part of the body

Question 17

triglycerides are broken down into

Answer 17

3 fatty acids and glycerol

Question 18

as the number of carbon double bonds in a lipid increases what happens to the boiling point

Answer 18

decreases

Question 19

what are the main products of lipid digestion

Answer 19

glycerol, fatty acids and monoglycerides

Question 20

describe the process of lipid absorption

Answer 20

absorbed into mucosal cells - coated with proteins becoming chylomicrons - enter lymph and blood stream - chylomicrons broken down at muscle/adipose tissue - free fatty acids are resynthesised into triglycerides

Question 21

what breaks chylomicrons down at muscle/adipose tissue

Answer 21

lipoprotein lipases

Question 22

what are the two fates of fatty acids once absorbed

Answer 22

converted to triglycerides for storage
oxidised for energy
(depends on the amount of energy at the time)

Question 23

by which process are fatty acids oxidised

Answer 23

beta oxidation

Question 24

before being oxidised what are fatty acids converted into

Answer 24

acyl-CoA

Question 25

to complete beta oxidation acyl-CoA is transported to ___ by the ___

Answer 25

matrix of mitochondria

carnitine shuttle - once in the mitochondria fatty acyl-carnitine is converted back into fatty acyl CoA

Question 26

how many steps are in each beta oxidation cycle

Answer 26

4

Question 27

after one step which products are yielded and how many

Answer 27

1 acetyl CoA
1 FADH2
1 NADH + H+
1 fatty acyl-CoA with 2 less carbons than before

Question 28

the overall effect of beta-oxidation is to produce ___ which can be transferred into ___

Answer 28

acetyl-CoA

tranferred into ketone bodies

Question 29

what are ketone bodies used for

Answer 29

energy metabolism in peripheral tissues

can trigger ketoacidosis in diabetics

Question 30

what is the role of muscle glycogen

Answer 30

not used to maintain blood glucose; provides energy via glycolysis and TCA cycle during physical activity