Glycolysis Flashcards
Respiration equation
Glucose + 6O2 –> 6CO2 + 6H2O
What is glycolysis?
Breaking down of Glucose
What happens in the prep phase of glycolysis
Phosphorylation of glucose and its conversion to glyceraldehyde 3-phosphate
What are the 3 main overall steps within the prep phase
1) first priming reaction
2) second priming reaction
3) Cleavage of 6 carbon sugar phosphate to 2 3-carbon sugar phosphates
Reaction 1 of the prep phase
1) is what
2) catalysed by what in tissues and in liver
3) reversible or irreversible
4) Uses what extras?
1) Phosphorylation of glucose. Glucose --> glucose6phosphate. 2) Catalysed by hexokinase in tissues Glucokinase in liver 3) Irreversible 4) ATP and Mg2+
Reaction 2 of the prep phase
1) is what
2) catalysed by what
3) reversible or nah?
4) What extras?
1) Isomerisation of Glucose 6 phosphate TO Fructose 6 phosphate
2) Catalysed by Phosphohexose Isomerase
3) Reversible
4) Mg2+
Reaction 3 of prep phase
1) is what
2) catalysed by what
3) reversible or nah?
4) what extras?
5) first what type of step?
1) Fructose 6 Phosphate TO Fructose 1,6 biphosphate
2) Catalysed by Phosphofructokinase 1 (PFK1)
3) Irreversible
4) ATP, Mg2+
5) First rate limiting step
Reaction 4 of prep phase
1) is what
2) catalysed by what
3) reversible or nah?
4) Feature of the enzyme
1) Cleavage of Fructose 1,6 Biphosphate.
Fructose 1,6 Biphosphate TO Dihydroxyacetone Phosphate + Glyceraldehyde 3 Phosphate
2) Aldolase
3) Reversible
4) Enzyme can catalyze the reverse reaction, which is more favourable
Reaction 5 of prep phase
1) is what
2) catalysed by what
3) Reversible or nah?
4) How does the enzyme work?
5) What amino acid performs the transfer in the enzyme
1) Isomerisation of DHAP to Glyceraldehyde 3 Phosphate
2) Triose phosphate isomerase
3) Reversible
4) Isomerase pulls a hydrogen atom off one carbon atom and replaces it on a neighbouring carbon atom.
5) A special glutamate amino acid in the active site (Glu165) performs the transfer
How many ATP are produced during the Prep phase?
Net loss of 2 ATP in the prep phase
What happens after the prep phase of glycolysis?
The payoff phase
What happens in the payoff phase?
Oxidative conversion of GA3P to pyruvate and the coupled formation of ATP and NADH
What are the 3 main steps in the payoff phase?
1) Oxidation and phosphorylation
2) First ATP forming reaction (Substrate level phosphorylation)
3) Second ATP forming reaction (Substrate level phosphorylation)
Reaction 6, first reaction of the payoff phase
1) is what?
2) catalyzed by what?
3) what extras are used?
4) what are the conditions?
1) Oxidation of GA3P TO 1,3Biphosphoglycerate
2) Glyceraldehyde 3 phosphate dehydrogenase
3) NAD+ is turned into NADH + H+
4) Activity of the enzyme depends on the turnover of NAD+ in the cytosol of the cell. Rapid turnover of NAD+ is only achieved under anaerobic conditions
Reaction 7, second reaction of the payoff phase
1) is what?
2) Catalysed by what?
3) What extras are used?
4) what is generated at the end finally
1) 1,3BPG to 3-Phosphoglycerate
2) Phosphoglycerate kinase
3) ADP and MG2+(Mg only for the reverse)
4) ATP. Transfers the phosphate from 13BPG to ADP to form ATP
Reaction 8, third reaction of the payoff phase?
a) is what?
b) catalysed by what?
c) what extras are used?
d) What is this step priming for?
a) 3-phosphoglycerate to 2-phosphoglycerate
b) Catalysed by phosphoglycerate mutase
c) Mg2+
d) Priming it for phosphate transfer to ADP for a later step
Reaction 9, fourth reaction of the payoff phase
1) is what?
2) Catalysed by what?
3) what is released
4) The enzyme is dependent on what?
1) 2 phosphoglycerate to Phosphoenolpyruvate
2) enolase
3) H2O so its a dehydration reaction
4) Mg2+
Reaction 10, fifth and final reaction of the payoff phase
1) is what?
2) catalysed by?
3) is the only what reaction of the payoff phase?
4) what does it produce?
1) Conversion of PEP to Pyruvate
2) Catalysed by Pyruvate kinase
3) irreversible. 3rd and final irreversible step of glycolysis
4) ATP
What is the overall stoichiometry of glycolysis?
Glucose + 2ATP + 2NAD+ + 4ADP + 2Pi ——> 2 pyruvate + 2 ADP + 2NADH + 2 H+ + 4ATP + 2 H20
Glycolysis proceeds up to 10x faster in cancer cells, so some chemotherapy agents inhibit what?
Hexokinase
The high glycolytic turnover in cancer cells is also used for what and how?
For diagnosis by injecting isotopically labelled glucose
What is the warburg hypothesis?
Most cancel cells produce energy by anaerobic glycolysis rather than oxidation of pyruvate in mitochondria which is common to healthy cells
Gluconeogenisis GNG is not simply what?
Is not simply the reverse of glycolysis
What is the main difference between GNG and glycolysis
The 3 irreversible steps of glycloysis are catalysed by different enzymes in GNG
