Name three respiratory substrates.

Glucose, fatty acids and amino acids.

Why does respiration in all organisms support evolution?

It suggests the pathways were inherited from a common ancestor (indirect evidence).

Is glycolysis aerobic or anaerobic?

Anaerobic: it does not need oxygen.

What is the starting material and end product of glycolysis?

Glucose (6C) is converted to two pyruvate (3C) molecules.

What happens in the first stage of glycolysis?

Glucose is phosphorylated to glucose phosphate using ATP, then to hexose bisphosphate.

What is formed when hexose bisphosphate splits?

Two molecules of triose phosphate.

What happens to triose phosphate?

It is oxidised to pyruvate, with NAD reduced to reduced NAD and ATP made.

How is ATP made in glycolysis?

By substrate-level phosphorylation.

What is the net gain per glucose in glycolysis?

2 ATP, 2 reduced NAD and 2 pyruvate.

GlycolysisAQA A-Level Biology: Flashcards

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What does respiration produce?

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What does respiration produce?: ATP.
Name three respiratory substrates.: Glucose, fatty acids and amino acids.
Why does respiration in all organisms support evolution?: It suggests the pathways were inherited from a common ancestor (indirect evidence).
Where does glycolysis occur?: In the cytoplasm.
Is glycolysis aerobic or anaerobic?: Anaerobic: it does not need oxygen.
What is the starting material and end product of glycolysis?: Glucose (6C) is converted to two pyruvate (3C) molecules.
What happens in the first stage of glycolysis?: Glucose is phosphorylated to glucose phosphate using ATP, then to hexose bisphosphate.
How many ATP are used in glycolysis per glucose?: Two.
What is formed when hexose bisphosphate splits?: Two molecules of triose phosphate.
What happens to triose phosphate?: It is oxidised to pyruvate, with NAD reduced to reduced NAD and ATP made.
How is ATP made in glycolysis?: By substrate-level phosphorylation.
What is the net gain per glucose in glycolysis?: 2 ATP, 2 reduced NAD and 2 pyruvate.

Exam questions on Glycolysis

Glycolysis was investigated in a cell-free extract of yeast, supplied with glucose, ATP, ADP, NAD and inorganic phosphate, in a sealed tube containing no oxygen.
Explain why glycolysis begins with the phosphorylation of glucose using ATP.2 marks
A biochemist measures the ATP and reduced NAD produced when glucose is converted to pyruvate in a cell-free extract, with all the enzymes and cofactors in excess.
Explain how glycolysis gives a net gain of two ATP per glucose molecule.2 marks
The metabolic poison iodoacetate inhibits the enzyme that oxidises triose phosphate during glycolysis. Cultured human cells in which glucose is the only respiratory substrate are treated with iodoacetate and supplied with glucose and oxygen.
Predict and explain the effect of iodoacetate on the concentration of triose phosphate and on the production of ATP and reduced NAD in the cells.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).