Glycolysis Flashcards
Where does glycolysis take place?
In the cytosol
For each glucose molecule that undergoes glycolysis, you have….
-2 ATP molecules (4 ATP produced minus 2 that are used)
-2 pyruvate (3-carbon molecules)
-2 NADH
What are priming reactions?
The first reactions require an input of energy in order to ‘’prime’’ glucose for its future energy production
What is the goal of priming reactions?
To allow glucose to be cleaved (cut) into two 3-carbon sugars
What is used to prime glucose (investment)?
(For priming reactions)
2 ATP molecules
What is oxidation and ATP formation (general)?
-The 3-carbon sugars are oxidized to produce 2 NADH molecules
-An organic phosphate is added to each of the sugars
-Two ATPs are produced by substrate level phosphorylation (for each 3-carbon sugar)
What is kinase?
Enzymes that catalyze the transfer of phosphate
What is phosphorylation?
ATP donates a phosphate group to the substrate molecule
What is dephosphorylation?
Phosphorylated substrate donates a phosphate group and ADP to form ATP
What is dehydrogenase?
Enzyme belonging to the group of oxidoreductases that oxidizes a substrate (energy rich molecule) by reducing an electron acceptor
A common electron acceptor is NAD+, which when reduced by electrons, in addition to getting a hydrogen, becomes NADH.
What is isomerase?
A general class of enzymes that converts a molecule from one isomer to another (isomers have the same chemical formula but their atoms are arranged differently)
What is mutase?
An enzyme of the isomerase class that catalyzes the movement of a functional group from one position to another within the same molecule
What is step 1 in glycolysis?
GLUCOSE PHOSPHORYLATION
The enzyme hexokinase transfers a phosphate from ATP to the carbon 6 of glucose, yielding glucose 6-phosphate
(This step requires energy)
What is step 2 in glycolysis?
ISOMERIZATION
The enzyme phosphoglucose isomerase converts glucose 6-phosphate to fructose 6-phosphate.
What is step 3 to glycolysis?
FRUCTOSE PHOSPHORYLATION
The enzyme phosphofructokinase adds a phosphate to fructose 6-phosphate, creating fructose 1,6-bisphosphate
(This step requires the input of energy)
What is step 4 in glycolysis?
CLEAVAGE
The enzyme fructose bisphosphate aldolase cleaves fructose 1,6-bisposphate, creating glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate
What is step 5 of glycolysis?
ISOMERIZATION
The enzyme triose phosphate isomerase converts dihydroxyacetone phosphate to glyceraldehyde 3-phosphate (G3P)
(Two G3P molecules have now been produced from the initial glucose)
What is step 6 in glycolysis?
OXIDATION
(All subsequent steps happen in double = 2xG3P)
-G3P is oxidized by the enzyme G3P dehydrogenase
-This rxn passes 2 electrons and a proton to NAD+, forming NADH.
-A phosphate molecule is added to G3P, yielding 1,3-bisphosphoglycerate
-The energy released in the redox rxn allows for the addition of the phosphate
What is step 7 in glycolysis?
ATP FORMATION
(All subsequent steps happen in double)
-The enzyme phosphoglycerate kinase removes a phosphate from 1,3-bisphosphoglycerate and transfers it to ADP, creating a molecule of ATP and 3-phosphoglycerate
-2 ATPs are made per molecule of glucose at this step. (Remember 1 glucose = 2 G3P)
-This is done by substrate level phosphorylation
What is step 8 of glycolysis?
ISOMERIZATION
(All subsequent steps happen in double)
-The enzyme phosphoglycerate mutase transfers the phosphate from carbon-3 to carbon-2, leaving 2-phosphoglycerate
What is step 9 of glycolysis?
DEHYDRATION
(All subsequent steps happen in double)
-A molecule of water is removed from 2-phosphoglycerate creating phosphoenolpyruvate (PEP).
-This step is crucial in the production of pyruvate, a molecule that is essential in the production of NADH and more ATP.
What is step 10 in glycolysis?
FORMATION OF ATP AND PYRUVATE
(All subsequent steps happen in double)
-pyruvate kinase removes the phosphate from PEP and transfers it to ADP, creating ATP and pyruvate (substrate level phosphorylation).
-This is the end of glycolysis
