Chapter 3 - Respiration.

Question 1

What are the two types of phosphorylation in respiration?

Answer 1

• Oxidative Phosphorylation.

- Substrate-level phosphorylation.

Question 2

What are the four stages in Aerobic Respiration?

Answer 2

• Glycolysis.
• Links reaction.
• The Krebs Cycle.
• Oxidative Phosphorylation.

Question 3

What is decarboxylation and what enzyme does it?

Answer 3

The removal of a carboxyl group from a molecule, releasing Carbon Dioxide. Decarboxylase.

Question 4

Where in the cell does glycolysis occur?

Answer 4

In the cell cytoplasm.

Question 5

Where does the Links reaction and the Krebs cycle occur?

Answer 5

In the mitochondrial matrix.

Question 6

Where does Oxidative Phosphorylation occur?

Answer 6

On the cristae of the inner mitochondrial membrane.

Question 7

How is glucose converted to pyruvate in Glycolysis?

Answer 7

2 ATPs are added to make Glucose Bisphosphate (6C). This is a very unstable molecule so it splits into 2 molecules of triose phosphate (3C). The are then dehydrogenated, oxidising them to pyruvate.

Question 8

What occurs in the links reaction?

Answer 8

Pyruvate is converted to Acetyl by removing a Hydrogen and a CO2 molecule by dehydrogenase and decarboxylase respectively. Acetyl is then joined to Coenzyme A which forms Acetyl Coenzyme A.

Question 9

What happens in the Krebs cycle?

Answer 9

• Acetyl CoA joins with Oxaloacetate(4c) to form citric acid(2c). (CoA regenerated).
• 6c compound dehydrogenated and decarboxylated to make a 5c compound.
• 5c dehydrogenated (NAD & FAD) and decarboxylated to make a 4c compound.
• The 4c compound can then repeat the cycle.

Question 10

How many NAD’s and FAD’s are produced from the krebs cycle?

Answer 10

NAD - 3

FAD - 1

Question 11

How many ATP does NAD and FAD make?

Answer 11

For every reduced NAD, 3 ATP are made (as all 3 proton pumps are used) and for every reduced FAD, 2 ATP are made (2 protein pumps used).

Question 12

What are the passage of electrons in the electron transport chain?

Answer 12

• NADH2 donates the electrons to the first electron carriers.
• The energy from these provide the energy for the first proton pump.
• The electrons pass along the chain providing energy for each of the proton pumps.
• Finally, they combine with H+ and O2 to form H2O.

Question 13

What are the passage of protons in the electron transport chain?

Answer 13

• The protons accumulate in the inter-membrane space.
• A concentration gradient is set up due to this.
• Due to the gradient, protons then diffuse down their electrochemical gradient through the stalked particle and through ATP synthase to join ADP +Pi to ATP.

Question 14

Why is Oxygen referred to as the ‘final electron acceptor’?

Answer 14

Because its essential to remove protons and electrons. O2 is reduced by the addition of hydrogen ions and electrons making water.