Biochemistry: glycogen metabolism

Question 1

what is glycogenesis

Answer 1

synthesis of glycogen from glucose

Question 2

what is glycogenolysis

Answer 2

breakdown of glycogen to form glucose

Question 3

what is gluconeogenesis

Answer 3

de novo synthesis of glucose from metabolic precursors(lactate, amino acids, glycerol)

Question 4

what is glycogen

Answer 4

main storage form of glucose

Question 5

when is liver glycogen used(broken down)

Answer 5

between meals to maintain blood glucose levels

Question 6

when is muscle glucose used(broken down)

Answer 6

to provide energy during physical activity

Question 7

what is the primary source of blood glucose overnight

Answer 7

gluconeogenesis

Question 8

describe the structure of glycogen

Answer 8

polymer consisting of glucose molecules

Question 9

describe the function of glycogenin

Answer 9

it is the protein attached to the primer required to add a glucose molecule onto an existing glycogen chain

Question 10

what is UDP-glucose

Answer 10

can be thought of as an ‘activated’ form of glucose

Question 11

describe the role of UDP-glucose in glycogen synthesis(glycogenesis)

Answer 11

it is an activated intermediate which is then synthesised to form glucose

Question 12

describe the role of glycogen synthase in glycogenesis

Answer 12

synthesises glycogen from UDP-glucose

it is the rate limiting enzyme of glycogenesis