lecture 3: glycogen, glycolysis

Question 1

what protein is located at the centre of the glycogen

Answer 1

glycogenin

Question 2

what is it and what is the function of glycogenin

Answer 2

is it a protein backbone

acts as an anchor for the glucose monors to eveually attach and form glycogen

Question 3

what branches off the glycogenin

Answer 3

glycogen branches!!

Question 4

is the glycogen only linear>?

Answer 4

no it is like a tree with linear and then branching segments

Question 5

what is responsible for breaking the glucose branches

Answer 5

branching enzymes

Question 6

where is glycogen stored and what is the purpose

Answer 6

stores in muscle and liver for energy storage for future use (exercise, rest, starvation)

Question 7

what are the 2 main bonds of the glycogen?

Answer 7

alpha 1-4 glycosidic bonds

alpha 1-6 glycosidic bonds

Question 8

which bonds are responsible for the linear portion of glucose

Answer 8

aplha 1-4 glycosidic

Question 9

which bonds are responsible for the branching part of glycogen

Answer 9

1-6 glycocidic bonds

Question 10

what does 1-4 mean or 1-6

Answer 10

there is a bond between the 1first carbon of a glucose and the 4 or 6 carbons of a different glucose which are bound by an oxygen molecule

Question 11

after how many glucose monomers do we get an 1-6 bond

Answer 11

5-8

Question 12

why is branching important

Answer 12

allows you to utilize many glucose monomers at once

Question 13

what is a strand of glycogen made up of

Answer 13

glucose monomers bound together

Question 14

true or false: glycogen is made up solely of reducing ends

Answer 14

no , made up of reducing and non reducing ends

Question 15

what are the two types of ends to the glycogen

Answer 15

reducing

non reducing

Question 16

which ends are sensitive to glycogen phosphorylase

Answer 16

non reducing ends

Question 17

what happens at the non reducing ends

Answer 17

sensitive to glycogen phosphorylase
this is where you can either build up or break down the glycogen
(these are the first glucose monomers to be cleaved for energy)

Question 18

what is the purpose of glycogen phosphorylase

Answer 18

breats down glycogen

(breaks away glucose monomers from he glycogen tree to go down the glycolotic pathway

Question 19

what is the function of glycogen synthase

Answer 19

to synthesize glycogen

Question 20

true or false: a main branch of glucose forms from the glycoenin protein

Answer 20

true

Question 21

what are the reducing ends of glycogen

Answer 21

the ends where there is no synthesis or breakdown of the glycogen tree
(these are the ends that are connected to glycogen)

Question 22

does the glycogen phosphorylase cleve off 1 or multiple glucose monomers at once

Answer 22

one at a time, very rapidly

Question 23

explain how glycogen phosphorate works

Answer 23

cleaves the monomers off at the non reducing end
uses inorganic phosphate to attach to that glucose
beomces glucose 1 phosphate and then that can go to glycolysis

Question 24

what does the breakdown/activation of the glycogen depend on

Answer 24

intensity of exercise

Question 25

what are the 4 enzymes involved in branching and debranching as well as storage/breakdown linearly?

Answer 25

1-6 bonds: branching and debranching enzymes 1-4: glycogen synthase and glycogen phosphorylase

Question 26

what is the function of the branching enzyme of glycogen

Answer 26

branching enzyme creates the 1-6 glycosidic bonds (branch)

Question 27

what is the function of the debranching enzyme

Answer 27

debranching cleaves/breaks the 1-6 bond

Question 28

do the branching and debraching enzymes work at the non reducing ends

Answer 28

no thats for the 1-4 bonds only

Question 29

what stimulates the glycogen synthase and the branching enzyme (the creation of more glycogen) and what is the function

Answer 29

insulin | allows us to store glycogen for future energy use

Question 30

what are the 2 main functions insulin

Answer 30

allows glucsoe uptake in the cell | stimulates glycogen synthase and branching enzyme

Question 31

is insulin (synthase and branching) important for glycogenesis or glycogenolysis

Answer 31

glycogenesis

Question 32

are glycogen phosphorylase and debranching important for glycogenesis or glycogenolysis

Answer 32

glycogenolysis

Question 33

where is insulin located

Answer 33

can be found in liver and muscles (secreted by beta cells of liver)

Question 34

what are the 3 stimulators of glycogen phosphorylase (glycogenolysis)

Answer 34

epinephrine glucagon AMP

Question 35

what are the two HORMONES that stimulate glycogenolysis

Answer 35

glucagon | epinephrine

Question 36

what is the product stimulator of glycogenolysis

Answer 36

AMP

Question 37

explain how glucagon is a stimulator

Answer 37

Glucagon is stimulated by the alhpa cells in the pancreas during exercise to signal the breakdown of the glycogen for glucose

Question 38

where is glucagon found

Answer 38

liver

Question 39

explain how epinephrine is a stimulator of glycogenolysis

Answer 39

when exercise is high, in the liver and in the muscle, stimulated to breakdown glycogen for energy

Question 40

is the relationship between exercise intensity and stimulators directly proportional or indirectly

Answer 40

directly as energy increases hormone secretion increases

Question 41

where is epinephrine found

Answer 41

liver and muscle cells

Question 42

where is the AMP stimulator found

Answer 42

muscle

Question 43

explain how AMP is a stimulator for glycogenolysis

Answer 43

During high intensity exercise, AMP will begin to accumulate in the cell When AMP is present, the cell knows there is a low energy source so it stimualtes glycogen phosloryza and debraching enzymes

Question 44

true or false: glycogenolysis and glycogenesis are supposed to happen at the same time

Answer 44

false, do not want these systems workign at the same time (coutner productuve)

Question 45

what are the two forms of glycogen phosphorylase

Answer 45

``` phosphorylase a (active) phosphoralase b(inactive) ```

Question 46

explain active vs inaction phosphorlaze

Answer 46

when there is a phophosphate bound to the glucogen phosphorylase, it is activated and will stimulate the breakdown of glycogen when the phosphate group is removed, you get glycogen phosphorylase b (inactive) which will inhibit glycogenolysis

Question 47

what inhibits the glycogen synthase

Answer 47

when a phosphate group is added to glycogen synthase, it is inhibited and cannot do glycogenesis

Question 48

what happens at the same time that glycogen phosphorylase is activated

Answer 48

when the enzyme for glycogenolysis is activated (has a phosphate group attached), the enzyme for glycogenesis (glycogen synthase) is INHIBITED by phosphorylation

Question 49

what is an example of a futile system

Answer 49

glycogenolysis and glycogenesis

Question 50

what is the protein/kinase that allows this activation/inhibition of the two systems at the same time

Answer 50

c (cyclic amp) dependent protein kinase

Question 51

do epinephrine and glucagon enter the cell to directly activate glycogenolysis

Answer 51

no , they simulate CAMP dependent protein kinase

Question 52

what is the function of Camp depending on protein kinase?

Answer 52

Activates glycogen phosphorylase (glycogenolysis) by adding an inorganic phosphate to the enzyme AT THE SAME TIME inhibits glycogen synthase (glycogenesis) by adding an inorganic phosphate to the enzyme

Question 53

who is the main contributor for the activation and inhibition of glycogenolysis and glycogenesis

Answer 53

C-amp depending protein kinase

Question 54

what is the breakdown of glycogen dependent on

Answer 54

exercise intensity (ie. light exercise=less rate of breakdown/ glycogenlosys)

Question 55

where is epinephrine/adrenaline released from

Answer 55

adrenale glands (adrenal medula)

Question 56

explain glycogen utilization during exercise

Answer 56

light exercsie: almost have 100% of glycogen content left (very light rate of glycogen breakdwon) moderate: over a 2 hour period, there is a graducal reduction of glyocgen from the msucle fibers doing the work heavy exercise: wont be able to exercise for long ebcause you will breakdown all the glycogen content

Question 57

what happens when the the glycogen content is at almost 0% in your muscles

Answer 57

muscles are fatigued because the myofibirls are almost totally depeleted of glycogen

Question 58

what are the two options for glucose 6 phosphate

Answer 58

1) glycogen synthesis | 2) glycolysis

Question 59

what are the first 4 steps of glycolysis and the energy requirements

Answer 59

Glucose > glucose 6 phosphate (1 ATP needed) Glucose 6 phophate >frucose 6 phosphate (no energy) fructose 6 phosphate> frcose 1,6 dispohoate (1 ATP NEEDED) fructise 1-6 diphosphates splits 2 atp deficit

Question 60

what happens once fructose 1-6 diphosphate is formed

Answer 60

the 6 carbon molecule will split into two 3 carbon entities

Question 61

when is atp start to be synthesized in glycolysis

Answer 61

after it splits into the 2 3 carbon units

Question 62

when is the first 2 atp manufactured in glycolysis

Answer 62

1-3 diphosphoglyceric acid to | 3 phosphoglyceric acid

Question 63

when is the last 2 atp's being made in glycolysis

Answer 63

phospholenulpyruvic > pyruvate | ADP>ATP by losing a phosphate

Question 64

what is the final product of glycolysis

Answer 64

2 pyruvic acids (pyruvate)

Question 65

what is the net energy yield of glycolysis

Answer 65

2 atp