Unit 2.2 Cellular respiration

Question 1

What is glycolysis?

Answer 1

The breakdown of glucose to pyruvate in the cytoplasm

Question 2

What are the stages of glycolysis?

Answer 2

-In the energy investment phase energy is required for the phosphorylation of glucose and other intermediates
-The phosphorylation leads to the generation of more energy during the energy-pay-off phase
-This results in a net gain of 2 ATP molecules

Question 3

What are the stages of the citric acid cycle?

Answer 3

• In aerobic conditions pyruvate is broken down to an acetyl group and carbon dioxide which is removed from the process. The acetyl group then combines with the co-enzyme A to form acetyl-co-A
  -The acetyl group from the acetyl-co-A will then combine with oxaloacetate to form Citrate which after many intermediates will be converted back into oxaloacetate, this results in the generation of ATP and the release of carbon dioxide

Question 4

Where does the citric acid cycle take place?

Answer 4

The matrix of the mitochondria (must be specific and say of the mitochondria)

Question 5

What is the role of dehydrogenase enzymes?

Answer 5

remove hydrogen ions and high energy electrons and pass them on to the co-enzyme NAD to form NADH which is then passed on to the electron transport chain. This process occurs both in glycolysis and the citric acid cycle

Question 6

Where does the electron transport chain take place?

Answer 6

The inner mitochondrial membrane

Question 7

What happens in the process of ATP synthesis?

Answer 7

-electrons are passed along the electron transport chain releasing energy
-This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane
-The flow of charged hydrogen ions through the membrane protein ATP synthase results in the production of ATP
-Hydrogen Ion and electrons combine with oxygen to form water

Question 8

What is the electron transport chain?

Answer 8

The electron transport chain is a series of carrier proteins attached to the inner mitochondrial membrane

Question 9

In what conditions does fermentation take place?

Answer 9

In the absence of oxygen

Question 10

What happens in the fermentation pathway of animals?

Answer 10

pyruvate is converted to lactate in a reversible reaction

Question 11

What happens in the fermentation pathway of plants/yeast?

Answer 11

Pyruvate is converted to ethanol and carbon dioxide in an irreversible reaction

Question 12

Does fermentation result in the production of ATP?

Answer 12

Yes it results in the production of 2 ATP from the glycolysis stage however much less ATP will be produced than in aerobic respiration

Question 13

What is the role of ATP?

Answer 13

ATP is used to transfer energy to cellular processes that require energy