lecture 3: glycogen, glycolysis Flashcards
what protein is located at the center of the glycogen
glycogenin
what is it and what is the function of glycogenin
is it a protein backbone
acts as an anchor for the glucose monors to eveually attach and form glycogen
what branches of the glycogenin
glycogen branches!!
is the glycogen only linear>?
no it is like a tree with linear and then branching segments
what is responsible for breaking the glucose branches
branching enzymes
where is glycogen stored and what is the purpose
stores in muscle and liver for energy storage for future use (exercise, rest, starvation)
what are the 2 main bonds of the gluycogen
alpha 1-4 glycosidic bonds
alpha 1-6 glycosidic bonds
which bonds are responsible for the linear portion of glucose
aplha 1-4 glycosidic
which bonds are responsbible for the branching part of glucogen
1-6 glycocidic bonds
what does 1-4 mean or 1-6
there is a bond between the 1first carbon of a glucse and the 4 or 6 carbon of a differnt glucse and are bound by an oxugen molecule
after how many glucose monomers do we get an 1-6 bond
5-8
why is branching important
allows you to utilize many glucose monomers at once
what is a strand of glycogen made up of
glucose monomers bound together
true or false: glycogen is made up solely of reducing ends
no , made up of recducting and non reducing ends
what are tje two types of ends to the glycogen
reducing
non reducing
which ends are sensitive to glycogen phosporylze
non reducing ends
what happens are the non reducing ends
sensitive to glycogen phosphorylze
this is where you can either build up or break down the glycogen
(these are the first glucose monomers to be cleaved for energy)
what is the purpose of glycogen phosphprlziae
breats down glycogen
(breaks away glucose monomers from he glycogen tree to go down the glycolotic pathway
what is the function of glycogen synthase
to synthesize glyxogen
true or false: a main branch of glucose forms from the glycoenin protein
trrue
what are the reducing ends f glycogen
the ends where there is no synthesis or breakdown of the glycogen tree
(these are the ends that are connected to glycogenin)
does the glycogen phsophrlzae cleve off 1 or multiple glucose monomers at once
one at a time, very rapidly
explain how glycogen phsolorate works
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
what does the breakdown/activation of the glycogen depend on
intensity of exercise
what are the 4 exnymes involved for branching and debraching as well as storage/breakdown lienarly
1-6 bonds:
branching and debranging enzymes
1-4:
glycogen synthase and glycogen phsophrylize
what is the function of the branching enzyme of glycogen
branching enzyme creates the 1-6 glycosidic bonds (branch)
what is the function of the debranching enzyme
debranaching cleaves/breaks the 1-6 bond town
do the branching and debraching enzumes work at the non reducing ends
no thats for the 1-4 bonds only
what stimulats the glycogen synthase and the branching enzyme (the creation of more glycogen) and what is the fucntion
insulin
allows us to store glycogen for future energy use
what are the 2 main fucntions insulin
allows glucsoe uptake in the cell
stimulates glycogen synthase and branching enzyme
is insulin (synthase and branching) important for glycogenesis or glycogenolysis
glycogenesis
are glycogen phoshorylze and debrachingimportant for glycogenesis or glycogebolysis
glycogenolysis
where is insulin located
can be found in lover and muscles (secreted by beta cells of liver)
what are the 3 stimulators of glyocgen phosrhorylze (glycogenolysis)
epinephrine
glucagon
AMP
what are the two HORMONES that stimulate glycogenolysis
glucagon
epinephrine
what is the product stimulator of glyocgenolysis
AMP
explain how glucagon is a stimuator
Glucagon is stimulated by the alhpa cells in the pancreas during exercise to signal the breakdown of the glycogen for glucose
where is glucagon found
liver
explain how epinegphrine is a stimulator of glycogenloysis
when exercise is high, in the liver and in te muscle, stimulated to breakdown glycogen for energy
is the relationship between exercise internsity and stimulators directly proportional or indicitrectl
directly
as energy increases
hormone secretion increases
where is epinephrine found
liver and muscle cells
where is the AMP stimulator found
muscle
explain how AMP is a stimulator for glycogenolysis
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
true or false: glycogenolysis and glycogenesis are supposed to happen at the same time
false, do not want these systems workign at the same time (coutner productuve)
what are the two forms og glycogen phosphorylaze
phosphorylza a (active) phosphoralaze b(inactaive)
explain active vs inaction phosphorlaze
when there is a phophosphate bound to the glucogen phospholaze, it is activated and will stimulate the breakdown of glycogen
when the phosphate group is removed, you get glycogen phosphorylaze b (inactive) which will inhibit glycogenlosis
what inhibits the glycogen synthase
when a phosphate group is added to glycgen syntahse, it is inhibited and cannot do glycogenesis
what happens at the same time that glycogen phosphorylze is activated
when the enzyme for glycogenolysis is activated (has a phosphate group attached), the enzyme for glycogenesis (glycogen syntahse) is INHIBITED by phosphrylzation
what is an example of a futile system
glycogenlosys and glycogenesis
what is the protein/kinase that allows this activation/inhbition of the two systems at the same time
c (cyclic amp) dependent protein kinase
do epinephrine and glucagon enter the cell to directly activate glycogenlysos
no , they simulate CAMP dpeendnet protein kinase
what is the fucntion of Camp depending protein kinase?
Activates glycogen phosphorylzase (glycogenolyssi) by adding an inorganic phosphate to the enzyme
AT THE SAME TIME
inhiits glycogen syntahse (glycogenesis) by adding an inorhanic phosphate to the enzyme
who is the main contributior for activation and inhibition of glycogenolysis and glycogensis
C-amp depending protein kinase
what is the breakdown of glycogen dependent on
exercise intensity (ie. light exercise=less rate of breakdown/ glycogenlosys)
where is eponephrine/adrenaline released from
adrenale glands (adrenal medula)
explain glycogen utilization durinf exercise
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
what happens when the the glycogen content is at almost 0% in your muscles
muscles are fatigued because the myofibirls are almost totally depeleted of glycogen
what are the two otpions for gluccose 6 phsophate
1) glycogen synthsis
2) glycolysis
what are the first 4 steps of glycolyis and the eneregy requirements
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
what hapennes once fructose 1-6 diphospate is formd
the 6 carbon molecule will split into two 3 carbon entities
when is atp start to be synthesized in glycolyis
after it splits into the 2 3 carbon units
when is the first 2 atp manufactured in glycolyssi
1-3 diphosphoglyceric acid to
3 phosphoglyceric acid
when is the last 2 atp’s being made in glycolysis
phospholenulpyruvic > pyruvate
ADP>ATP by losing a phosphate
what is the final product of glycolysis
2 pyruvic acids (pyruvate)
what is the net energy yield of glycolysis
2 atp
