Part 1: Aerobic and Anaerobic Respiration

Question 1

What is the difference between respiration and breathing? (2)

Answer 1

1. Breathing is a mechanical process.
2. Respiration is a chemical reaction that takes place inside cells to release energy from food.

Question 2

What does ‘aerobic’ mean?

Answer 2

Using oxygen/ with oxygen

Question 3

Energy is released from glucose…

Answer 3

…by a process known as respiration.

Question 4

During respiration, chemical reactions take place…

Answer 4

…inside the mitochondria in the cells of your body.

Question 5

When glucose reacts with oxygen…

Answer 5

… energy is released.

Question 6

Carbon dioxide and water…

Answer 6

… are formed as waste products.

Question 7

The process is known as aerobic respiration…

Answer 7

… because it uses oxygen from the air.

Question 8

Explain whether or not plants respire. (2)

Answer 8

1. Yes because they are organisms
2. They need energy for metabolic processes, such as respiration and active transport.

Question 9

When and where does aerobic respiration take place? (2)

Answer 9

1. All of the time
2. In every cell and in the mitochondria of the cell.

Question 10

Substrates used in aerobic respiration: (2)

Answer 10

1. Glucose
2. Oxygen

Question 11

What is the energy that is released from aerobic respiration used for?

Answer 11

Making new proteins (from amino acids)

Question 12

What happens when aerobic respiration takes place faster? (2)

Answer 12

1. Releases more heat
2. More activity in the cell due to increased kinetic energy.

Question 13

What else is required for aerobic respiration?

Answer 13

Enzymes

Question 14

In which structure in the cell does aerobic respiration take place?

Answer 14

The mitochondria

Question 15

Describe the mitochondria. (4)

Answer 15

1. Highly folded inner membrane which provides a large surface area for enzymes involved in aerobic respiration.
2. Tiny, rod shaped organelles
3. Found in animal, plant, fungal and algal cells
4. The more active a cell, the more mitochondria it will contain.

Question 16

Explain why a muscle cell has more mitochondria than a fat cell. (2)

Answer 16

1. The more active a cell is the greater its energy requirement, so the more mitochondria it needs.
2. Muscle cells are more active than fat cells.

Question 17

State the word equation for aerobic respiration.

Answer 17

Glucose + oxygen —-> carbon dioxide + water vapour (releases energy)

Question 18

How much energy does aerobic respiration release?

Answer 18

A lot more energy than anaerobic respiration (it is an exothermic reaction)

Question 19

Explain why aerobic respiration is a slower process than anaerobic respiration.

Answer 19

It is a longer process with many more steps (and therefore requires more enzymes).

Question 20

When does anaerobic respiration take place?

Answer 20

When there is insufficient oxygen, or no oxygen at all so the oxidation of glucose is incomplete.

Question 21

State the substrate used in anaerobic respiration.

Answer 21

Glucose

Question 22

In which structure in the cell does anaerobic respiration take place?

Answer 22

The cytoplasm

Question 23

Why do red blood cells use anaerobic respiration?

Answer 23

They have no mitochondria

Question 24

State the word equation for anaerobic respiration in animals.

Answer 24

Glucose → lactic acid (releases energy)

Question 25

Why is anaerobic respiration faster than aerobic respiration?

Answer 25

It is a shorter process with fewer stages.

Question 26

How much energy does anaerobic respiration release? (3)

Answer 26

1. Less energy than aerobic respiration. 2. Because it occurs when there is insufficient oxygen or no oxygen at all. 3. Meaning the oxidation of glucose is incomplete.

Question 27

What problems occur when anaerobic respiration occurs over a prolonged period? (2)

Answer 27

1. Not sustainable for long periods as lactic acid builds up in the muscles. 2. Causing muscle fatigue

Question 28

State the symbol equation for aerobic respiration.

Answer 28

C6H12O6 + 6O2 → 6CO2 + 6H20

Question 29

What isnmeant by the term 'oxygen debt'.

Answer 29

1. Build up of lactic acid 2. **The volume of oxygen needed to break down the lactic acid.*

Question 30

Explain why heart rate and breathing rate remain high for a period after exercise. (3)

Answer 30

1. To supply extra oxygen 2. The fitter you are, the quicker you remove the oxygen debt 3. After exercise, blood takes the lactic from the muscles to the liver to be converted back into glucose.

Question 31

State the word equation for anaerobic respiration **in plants and yeast.**

Answer 31

Glucose → ethanol + carbon dioxide (releases energy)