glycogen metabolism P2.

Question 1

Whyy have glycogen store when fat gives more energy?

Answer 1

• fat has more C than sugar… so adds to E difference..
• fat also gives more E, bc it is reduced to C and H bonds only… compared to glucose, way more reduced

why not use fat then?
1. takes a long time to mobilize fat and cant metabolize fat without O2 (done in the mitochondria, which doesnt work without O2)

Question 2

glycogen particle

Answer 2

exist as cytoplasmic granuole… with the necessary enzymes to break make and regulate… but does not contain ALL of the regulatory enzymes

Question 3

glycogen contains

Answer 3

a lot of glucose units, and they are mostly linked a(1-4), byut every 8-12 glucose units is an a(1-6) branch, this allows for branched structure.

Question 4

nonreducing end and reducing end

Answer 4

reducing end = has a hemiacetal

Question 5

structure of glycogen

Answer 5

• branched structure, why not linear?
  can have simultaneous breakdown at non-reducing ends (acetal portion, removing sugar by phosphorolysis)… on every single nonreducing ends, can use phosphorylase pulling off glucose units. allows you to rapidly use glucose, which is good.

Question 6

3 enzymes involved in glycogen breakdown pathway

Answer 6

glycogen phosphorylase (GP… technically PH, but GP easier to remember), wil catalyze rds which is a phosphorolysis… negative ∆G in body.

debranching Enzyme (DBE), hydrolyze a(1-6) linkage

Phosphoglucomutase (PGlucM) converts G1P to G6P, which can be used in many pathways. Muscle = glyc Liver = dumping gluc into blood stream.

Question 7

what is phosphorolysis

Answer 7

breaking with Pi as the breaking agent.

Question 8

glycogen phosphorylase

Answer 8

key regulatory enzyme with very complex regulation

products are G1P (synthesis and breakdown) and a glycogen chain shorter by 1 gluc unit