Respiration-REACTIONS Flashcards
What immediately happens to glucose in glycolysis and what is formed?
Glucose is phosphorylated twice by 2 ATP molecules forming Hexose-6-bisphosphate and 2 ADP.
How many carbons does glucose have?
6
How many carbons does hexose-6-bisphosphate have?
How many phosphate groups?
6 carbons
2 phosphate
What immediately happens to hexose-6-bisphosphate in glycolysis?
It splits in half, forming two triose phosphate molecules.
How many carbons does triose phosphate have?
How many phosphate groups?
3 carbons
1 phosphate
What happens to triose phosphate in glycolysis and what is formed?
Triose phosphate is phosphorylated by inorganic phosphate.
Triose phosphate is dehydrogenated (oxidised) by NAD+, this forms reduced NAD.
Triose phosphate phosphorylates ADP into ATP in substrate-level phosphorylation. (TWICE)
This results in Pyruvate.
What is the first chemical in the link reaction and what must happen in between glycolysis and the link reaction?
Pyruvate enters the mitochondrial matrix from the cytoplasm through active transport.
What happens to pyruvate in the link reaction to form acetate?
Pyruvate is decarboxylated (carbon dioxide produced).
It is then dehydrogenated (oxidised) by NAD+ producing reduced NAD.
What happens to acetate in the link reaction?
Acetate is added to coenzyme A forming Acetyl CoA.
How many carbons does acetyl CoA have?
2
What is the name of the enzyme that coordinates and catalyses the link reaction?
Pyruvate dehydrogenase complex.
What immediately happens to acetyl CoA in the krebs cycle?
Acetyl CoA and Oxaloacetate join and coenzyme A is lost.
This forms Citrate.
How many carbons does oxaloacetate have?
4
How many carbons does citrate have?
6
What happens to citrate in the krebs cycle to form oxaloacetate?
Carbon dioxide is released. NAD+ is reduced. Carbon dioxide is released. NAD+ is reduced. ATP is produced in substrate-level phosphorylation. FAD is reduced. NAD+ is reduced.
Why does one glucose molecule power 2 turns of the krebs cycle?
A single glucose molecule produces 2 acetyl CoA molecules after the processes of glycolysis and the link reaction.
What are reduced NAD and FAD used for in oxidative phosphorylation?
They are oxidised to release 2H+ and 2e-.
The electrons power the proton pumps via the ETC and the hydrogen ions are pumped into the intermembrane space.
What is the final electron acceptor in oxidative phosphorylation and what is produced?
O2 combines with 4H+ and 4e- to form two water molecules.
Why must there be a hydrogen acceptor in fermentation?
Reduced NAD must be oxidised in order for glycolysis to continue and ATP to continue to be produced via substrate-level phosphorylation.
What is the hydrogen acceptor in alcoholic fermentation and what is formed?
Ethanal forming Ethanol.
What is the hydrogen acceptor in lactate fermentation and what is formed?
Pyruvate forming Lactate.
What enzymes are required for alcoholic fermentation?
Pyruvate dercarboxylase and ethanol dehydrogenase.
What enzyme is required in lactate fermentation?
Lactate dehydrogenase
What is the Q10 temperature coefficient for a biochemical reaction?
The ratio of the rate of reaction at a temperature t+10 over the rate of reaction at t
What is decarboxylation?
The removal of carbon dioxide.
What is dehydrogenation?
The removal of hydrogen (oxidation)
How many ATP molecules are produced via substrate level phosphorylation in one “turn” of the krebs cycle?
1
What are the advantages of lipids as respiratory substrates over carbohydrates/protein?
Why is this?
Lipids have higher energy density than glucose/protein.
This is due to a higher proportion of carbon-hydrogen bonds.
What coenzymes are used in respiration?
NAD, FAD, coenzyme A
How many ATP molecules are produced in glycolysis?
2 ATP molecules are used to convert glucose into hexose-6-bisphosphate.
2 ATP molecules are produced during the oxidation of triose phosphate to pyruvate (so 4 for each glucose molecule).
So a net of 2 ATP molecules are produced for one glucose molecule by glycolysis.
