Lesson test: Glycolysis and fermentation

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Glycolysis and fermentation

1.[1p]
Glycolysis invests two ATP and produces four. What is the net yield of ATP per glucose?

CorrectNot quite: 2

2.[2p]
Why does the pathway spend two ATP before earning any?

Phosphorylation traps the sugar inside the cell, commits it to the pathway, and sets up a molecule that can be cleaved in half

Correct

Because ATP is the only phosphate source available

The answer is: Phosphorylation traps the sugar inside the cell, commits it to the pathway, and sets up a molecule that can be cleaved in half

To raise the temperature of the cytosol

The answer is: Phosphorylation traps the sugar inside the cell, commits it to the pathway, and sets up a molecule that can be cleaved in half

To reduce NAD⁺ to NADH before the split

The answer is: Phosphorylation traps the sugar inside the cell, commits it to the pathway, and sets up a molecule that can be cleaved in half

3.[3p]
In the glyceraldehyde 3-phosphate dehydrogenase step, where does the phosphate that ends up in ATP come from?

Free inorganic phosphate in solution, captured as an acyl phosphate using the energy of an oxidation

Correct

From a second molecule of ATP

The answer is: Free inorganic phosphate in solution, captured as an acyl phosphate using the energy of an oxidation

From the phosphate already on glucose 6-phosphate

The answer is: Free inorganic phosphate in solution, captured as an acyl phosphate using the energy of an oxidation

From NAD⁺

The answer is: Free inorganic phosphate in solution, captured as an acyl phosphate using the energy of an oxidation

4.[2p]
Two ATP at the standard 30.5 kJ/mol are captured from a glucose containing 2870 kJ/mol. What percentage of the available energy is that, to one decimal place?

CorrectNot quite: 2.1

5.[1p]
Fermentation to lactate or ethanol yields additional ATP beyond what glycolysis has already made.

True

The answer is: False

False

Correct

6.[3p]
What is fermentation actually for?

Reoxidising NADH so that NAD⁺ is available and glycolysis can keep running

Correct

Extracting the remaining energy from pyruvate

The answer is: Reoxidising NADH so that NAD⁺ is available and glycolysis can keep running

Producing carbon dioxide for the cell to excrete

The answer is: Reoxidising NADH so that NAD⁺ is available and glycolysis can keep running

Neutralising the acid produced by glycolysis

The answer is: Reoxidising NADH so that NAD⁺ is available and glycolysis can keep running

7.[2p]
Match each molecule to its role in glycolysis.

Phosphofructokinase
1,3-bisphosphoglycerate
Phosphoenolpyruvate
Lactate dehydrogenase

a donor whose power comes from tautomerisation after transfer
an acyl phosphate that donates phosphate to ADP
regenerates NAD⁺ in muscle
the committed step and the main control point

Show the answer

Phosphofructokinase: the committed step and the main control point 1,3-bisphosphoglycerate: an acyl phosphate that donates phosphate to ADP Phosphoenolpyruvate: a donor whose power comes from tautomerisation after transfer Lactate dehydrogenase: regenerates NAD⁺ in muscle

8.[2p]
Which regulators act on phosphofructokinase, and in the direction stated?

Select all that apply

ATP inhibits it

Correct

AMP activates it

Correct

Citrate inhibits it

Correct

Lactate activates it

The answer is: ATP inhibits it, AMP activates it, Citrate inhibits it

9.[2p]
Put these glycolytic species in the order they appear.

Phosphoenolpyruvate
Glucose 6-phosphate
Fructose 1,6-bisphosphate
Glyceraldehyde 3-phosphate
Pyruvate

Show the answer

a, b, c, d, e

1.[1p] Glycolysis invests two ATP and produces four. What is the net yield of ATP per glucose?

2.[2p] Why does the pathway spend two ATP before earning any?

3.[3p] In the glyceraldehyde 3-phosphate dehydrogenase step, where does the phosphate that ends up in ATP come from?

4.[2p] Two ATP at the standard 30.5 kJ/mol are captured from a glucose containing 2870 kJ/mol. What percentage of the available energy is that, to one decimal place?

5.[1p] Fermentation to lactate or ethanol yields additional ATP beyond what glycolysis has already made.

6.[3p] What is fermentation actually for?

7.[2p] Match each molecule to its role in glycolysis.

8.[2p] Which regulators act on phosphofructokinase, and in the direction stated?

9.[2p] Put these glycolytic species in the order they appear.

1.[1p]
Glycolysis invests two ATP and produces four. What is the net yield of ATP per glucose?

2.[2p]
Why does the pathway spend two ATP before earning any?

3.[3p]
In the glyceraldehyde 3-phosphate dehydrogenase step, where does the phosphate that ends up in ATP come from?

4.[2p]
Two ATP at the standard 30.5 kJ/mol are captured from a glucose containing 2870 kJ/mol. What percentage of the available energy is that, to one decimal place?

5.[1p]
Fermentation to lactate or ethanol yields additional ATP beyond what glycolysis has already made.

6.[3p]
What is fermentation actually for?

7.[2p]
Match each molecule to its role in glycolysis.

8.[2p]
Which regulators act on phosphofructokinase, and in the direction stated?

9.[2p]
Put these glycolytic species in the order they appear.