KA7-Respiration

Question 1

What is respiration?

Answer 1

Respiration is the process by which chemical energy is released from food using oxygen.

Question 2

What is ATP?

Answer 2

A high nerdy molecule made up of adenosine and three phosphate molecules.

Question 3

What is phosphorylation?

Answer 3

An enzyme controlled process by which a phosphate group is added to a molecule.

Question 4

What are the three stages to respiration?

Answer 4

Glycolysis, citric acid cycle and electron transport chain.

Question 5

Describe glycolysis.

Answer 5

1. Glycolysis occurs in the cytoplasm and it does’nt require oxygen.
2. Glycolysis has two sub stages called the energy investment stage and the energy pay off stage.
3. In the energy investment stage 2ATP are used up for the phosphorylation of glucose and intermediate compound.
4. In the energy pay off stage, the intermedite compound breaks down into two pyruvate moleules, with a net gain of 2ATP.
5. Dehydrogenese enzyme removes H+ and electrons.
6. The coenzyme NAD picks up the H+ and electrons to form NADH+ and is carried to the third stage.

Question 6

Describe Citric Acid Cycle.

Answer 6

1. Citric acid cycle occurs in the matrix of the mitochondria and it requires oxygen.
2. In this stage pyruvate is broken down into an acetyl group. Acetyl combines with coenzyme A to form acetyl coenzyme A.
3. The acetyl from acetyl coenzyme A combines with oxaloacetate to form citrate.
4. During a series of enzyme controlled steps citrate is converted back into oxaloacetate, which results in the generation of ATP and release of carbon dioxide.
5. Dehydrogenase enzyme removes H+ and electrons, which are passed to NAD forming NADH+.

Question 7

Describe Electron Transport Chain.

Answer 7

1. This stage occurs in the inner membrane of the mitochondria.
2. NADH+ drops off H+ and electrons pass along the electron transport chain and release energy.
3. This energy released by electrons pumps H+ across the membrane through active transport.
4. These H+ diffuse back through ATP synthase generating ATP.
5. Finally, electrons and H+ combine with oxygen to form water

Question 8

What is the role of ATP?

Answer 8

To transfer energy to cellular processes which need energy. E.g. DNA replication, protein synthesis.