U2.2 Cellular respiration

Question 1

Define respiration.

Answer 1

The breakdown of respiratory substrates to release energy.

Question 2

What is glycolysis?

Answer 2

The breakdown of glucose to pyruvate in the cell cytoplasm.

Question 3

Name the two phases of glycolysis.

Answer 3

The energy-investment phase and the energy pay-off phase.

Question 4

What is required to phosphorylate glucose and intermediates during the energy-investment phase of glycolysis?

Answer 4

ATP (adenosine triphosphate)

Question 5

What does phosphorylation in the energy-investment phase of glycolysis result in?

Answer 5

The generation of more ATP in the energy pay-off phase.

Question 6

What is there a net gain of in glycolysis?

Answer 6

2ATP

Question 7

What is the end product of glycolysis?

Answer 7

Pyruvate

Question 8

What happens to pyruvate in aerobic conditions?

Answer 8

It is broken down to an acetyl group.

Question 9

What does acetyl combine with, and what does it form?

Answer 9

Combines with coenzyme A to form acetyl coenzyme A.

Question 10

Where does the citric acid cycle occur?

Answer 10

In the matrix of the mitochondria.

Question 11

Where does glycolysis occur?

Answer 11

In the cytoplasm.

Question 12

What does the acetyl group of acetyl coenzyme A combine with, and what does it form?

Answer 12

Combines with oxaloacetate to form citrate.

Question 13

What is citrate converted back to, and how?

Answer 13

Oxaloacetate in a series of enzyme-controlled steps.

Question 14

What does the citric acid cycle yield?

Answer 14

ATP and carbon dioxide.

Question 15

What enzyme is involved in glycolysis and the citric acid cycle? What does it do?

Answer 15

Dehydrogenase enzymes.

Removes hydrogen ions and electrons from metabolites and pass them to the coenzyme NAD to form NADH.

Question 16

What are passed through the electron transport chain?

Answer 16

Hydrogen ions and electrons.

Question 17

Where is the electron transport chain located?

Answer 17

The inner mitochondrial membrane.

Question 18

What is the electron transport chain?

Answer 18

A series of carrier proteins on the inner mitochondrial membrane.

Question 19

Why are electrons passed along the ETC?

Answer 19

To release energy.

Question 20

What does energy released from the ETC allow?

Answer 20

Hydrogen ions to be pumped across the inner mitochondrial memebrane.

Question 21

What does the flow of hydrogen ions through the membrane protein ATP synthase produce?

Answer 21

ATP

Question 22

What combines to form water in the ETC?

Answer 22

Hydrogen ions and electrons combine with oxygen.

Question 23

Where and when does fermentation occur?

Answer 23

In the cell cytoplasm in the absence of oxygen.

Question 24

Compare fermentation and aerobic respiration in terms of ATP production?

Answer 24

Much less ATP production in fermentation than aerobic respiration.

Question 25

Describe fermentation in animal cells.

Answer 25

Pyruvate is converted to lactate and this is a reversible reaction.

Question 26

Describe fermentation in plants and fungi.

Answer 26

Pyruvate is converted to ethanol and carbon dioxide and this is an irreversible reaction.

Question 27

What is ATP used for?

Answer 27

To transfer energy to processes which require energy.

Question 28

Name 5 cellular processes that require energy.

Answer 28

Protein synthesis, contraction of muscles, active transport, DNA replication and carbon fixation.