Glycogen digestion and mobilisation (glycogenolysis)

Question 1

describe digestion and absorption

Answer 1

starches use amylase to go to maltose/limit dextrins; maltase and limit dextrase breaks down to glucose
lactase and sucrase also
glucose absorbed across epithelial cells in small intestines to blood.

Question 2

describe glycogenolysis

Answer 2

glycogen + Pi — glycogen phosphorylase —> glucose-1-phosphate + glycogen
process continues till 4 units from a branch are reached
debranching enzyme - transferase
debranching enzyme - alpha-1,4-glucosidase
continues till all converted to glucose-1-P
G-1-P –phosphoglutomutase –> G-6-P

Question 3

fate in muscles?

Answer 3

direclty enters glycolysis

Question 4

fate in liver?

Answer 4

enters ER through G6P transporter
glucose 6 phosphatase enzyme (only found in liver) breaks down to glucose and Pi
tranposrted out of ER by transporters
GLU2 transports glucose out of cell; goes into bloodstream

Question 5

advantage of glycogenolysis to G-6-P and not glucose?

Answer 5

charged phosphate group means it cant leave cell

etners second step of glycolysis, so it needs one less ATP