glycolysis Flashcards
glucose molecule
6 carbon molecules
where does glycolysis take plaace
cytoplasma
is glycolyssi still possible if 02 is low
yes
anabolism
buildup
cataboism
breakdown
energy conusming phase
requires atp
energy producing phase
geenrares atp
what happens in response to high blood glucose
pancreatic beta cells secrete insulin
how does glucose get inside the clels
utilizes glucose transporters, or GLUT, which are on the cell membrane.
where are GLUT found
on cell membrane
what happens once glucose is iinside the cell
prevented from diffusing across the cell membrane back into the circulation by enzymes
kinases
enzymes which prevent glucose from diffusig across the cell membrane back into circulation
what phosphorylates glucose
kinases
what changes the shape of the glucose molecu;e
a phosphate groupp haven being added
what does the frist phosphate come from and result in
breakdown of atp into adp so drops us to -1 on energy cpunter
how is glucose turned into glucose 6 phosphate
hezokinase and glucokinas add a phosphate group to the 6th carbon in the glucose molecole
where is hexokinase found
in all cells
where is glucokinase found
liver cells and beta cells of panceas (induced by presence of insulin)
is the firts step reversible
no
isomer of glucose 6 phosphate
fructose 6 phosphate
role of phosphoglucoisomerase
converts Glucose-6-phosphate to fructose-6-phosphate
what is Fructose-6-phosphate phosphorylated by
phosphofructokinase-1, or PFK1
role of phosphofructokinase-1, or PFK1
adds a phosphate to the 1st carbon on the fructos moleucle making fructose-1,6-bisphosphate.
what makes us -2 on the enrgy counter
phosphofructokinase-1, or PFK1 adding a phosphate to fructose 6 phosphate
rate limitting step
how fast PFK1 converts fructose-6-phosphate to fructose-1,6-bisphosphate determines the speed at which all of glycolysis happens.
how do cells regulate PFK1
by using another enzyme called phosphofructokinase 2 - or PFK2.
can PFK2 phosphorykate glucose aswell as PFK1
yes howevrr it adds a phosphate to the second carbon instead making fructose 2 6 bisphosphate
what acitvates PFK2
insulin so when blood glcuose is up post meal
what does incraesed levels offructose-2,6 bisphosphate activate
PFK1
what does more PFK1 mean
the slowest step in glycolysis speeds up, and more glucose is turned into energy
what does the pancreas secrete whe glucose is low
glucagon
glucagon function
inhibits PFK2, resulting in less fructose-2,6-bisphosphate, which inhibits PFK1, decreasing the rate of PFK1 enzymes, and that slows down glycolysis
what else inhibits PFK1
citrate and ATP as cell has lots of enerfgy so doesnt need more
what happens when the cells DO need energy
PFK1 becomes very active in creating fructose 1 6 bisphosphate
what is Fructose 1,6 bisphosphate cleaved by
enzyme adolase into 3 carbon molecules - glyceraldehyde-3-phosphate, or G3P, and dihydroacetone-phosphate, or DHAP.
complication of DHAP
cant go down glycolysis pathwya so an isomerase converts it into G3P
ho many g3p molecules are made per glucose
2
what is g3p converte dinto
1,3 bisphosphoglycerate, or 1,3-BPG, by an enzyme called G3P-dehydrogenase.
role of G3P-dehydrogenase
removes a hydrogen from G3P and gives it to a nearby NAD+ molecule, making NADH as a byproduct and adds a phosphate group to the 1st carbon of G3P, making 1,3-BPG
how many nadh molecules are made
2 as there are two g3ps
pathwya of nadh
enters the electron transport chain in the mitochondria and makes roughly 3 ATP.
role of phosphoglycerate kinase
removes a phosphate from the 1st carbon of 1,3-BPG and gives it to ADP, making 3-phosphoglycerate, and ATP as a byproduct
energy counter post phosphoglycerate kinase role
0
mutase role
moves the phosphate on 3-phosphoglycerate to the 2nd carbon, making 2-phosphoglycerate
enolase role
removes a water molecule from 2 phosphoglycerate and makes phosphoenolpyruvate - or PEP
pyruvate kinase role
transfers a phosphate from PEP to ADP, making pyruvate, and ATP as a byproduct
atp counter post pyrivate kinase
2
feedforward regulation
fructose-1,6 bisphosphate upregulates pyruvate kinase
what downregulates pyruvate kinase activity
high levels of ATP and the amino acid alanine
where does alanine come from
from skeletal muscle when fastingw
what does high levels of alanine signal
that the body needs to make new glucose
how many atp made
2
is glycolysis anaerobic or aerobic
anaerobic
how many atp used
4
end product of glycolysis
pyruvate
