Glycolysis Flashcards
where does glycolysis, TCA and oxidative phosphorylation take place?
glycolysis in the cytoplasm
tricarboxylic acid (TCA) cycle and oxidative phosphorylation in the mitochondria
Role of hydrolysis to do with phosphates
phosphate groups classified as ‘high’ energy (highly exergonic)
e.g. in phosphoenolpyruvate (lose Pi easily)
‘low’ energy e.g. in glucose-6-phosphate
on the bases of the extent that it would hydrolyse in water
Things that are high in energy help make ATP by losing Pi that can be used to make ADP into ATP and those that are low in energy dont lose Pi easily so ATP adds Pi
In glucose-6-phosphate, what does the 6 refer to?
Phosphate is attached to the 6th carbon on glucose?
How many carbons are there in 4 of the metabolites in glycolysis?
6
How many carbons are there in the remaining metabolites?
3
The term glycolysis is derived from Greek, ‘glykys’, sweet and ‘lysis’, dissolution – this refers to the cleavage of glucose, a 6 carbon sugar, in to 2×3 carbon sugars in the process. In which reaction does this occur?
Reaction 4 catalysed by aldolase
What type of chemical group do all the metabolites in glycolysis (other than glucose and pyruvate) contain?
phosphate
What inorganic ion is required for glycolysis?
inorganic phosphate
What is the other source of phosphate groups in glycolysis?
ATP
How many reactions involve ATP/ADP?
4
What is happening in these reactions?
phosphate transfer
What type of enzyme catalyses these reactions?
kinases
The ‘energy-investment’ phase of glycolysis consists of reactions 1-5: per glucose, how much ATP is used in this phase?
2
The ‘energy-return’ phase of glycolysis consists of reactions 6-10: per glucose, how much ATP is produced in this phase?
4
What is the net yield of ATP in converting 1 glucose to 2 pyruvate?
2
Two metabolites in glycolysis have a a high ‘energy’ phosphate group. Which are they?
1,3-bisphosphoglycerate and phosphoenolpyruvate
How many reactions in glycolysis involve isomerisations?
3
How many phosphate shift reactions are there in glycolysis?
1
Which reactions involve aldose-ketose isomerisations?
Reaction 2 and 5
What would happen if reaction 2 did not occur?
We need to be able to split it into two equal things otherwise glycolysis would not happen
Which reaction is a redox reaction?
reaction 6 catalysed by GAP dehydrogenase enzymes
What is the yield of NADH in converting 1 glucose to 2 pyruvate?
2
Why do we have Fermentation pathways
Because supply of NAD+ limited
NAD+ must be regenerated for glycolysis to continue
aerobic conditions
NADH ultimately oxidised by oxygen
anaerobic conditions
NADH oxidised by a metabolite
extension of the glycolytic pathway
fermentation: glycolysis plus the NAD+ regenerating extension
e.g. lactic and alcoholic fermentations
Lactic fermentation
active skeletal muscle
poor supply of oxygen but high demand for ATP
lactic fermentation
lactate dehydrogenase catalyses oxidation of NADH by pyruvate = NAD+ and lactate
lactic acid =lactate + H+
H+ build up (acidity) causes muscle cramps
