1.6 Respiration

Question 1

What is respiration?

Answer 1

Respiration is a sereis of enzyme-controlled reactions that releases the chemial energy stored in glucose

Question 2

Identify the chemicals that control the rate of respiration reactions

Answer 2

Respiration reactions, like all chemical reactions inside living cells are controlled by enzymes

Question 3

Identify the chemicals generated by respiration that is used fo transferring energy in cells

Answer 3

The chemical energy released from glucose by respiration is used to generate a chemical called ATP. This ATP is then used to transfer energy to the other chemical reactions inside a cell

Question 4

Give examples of cellular activities that require energy transferred by ATP

Answer 4

• Muscle cell contraction
• Cell division/ Mitosis
• Protein synthesis
• Transmission of nerve impulses

Question 5

Name the types of respiration pathways that can occur in the presence and absence of oxygen

Answer 5

respiration in the presence of oxygen = Aerobic respiration
Respiration in the absence of oxygen= Fermentation pathway

Question 6

Identify the molecules released during the first stage of respiration

Answer 6

During the first stage of respiration glucose (6C) is broken down to release 2 molecules of pyruvate (3C) and a small quantity of energy in the form of 2 molecules of ATP

Question 7

What is the summary word equation for aerobic respiration

Answer 7

glucose+Oxygen —- carbon dioxide + water + energy

Question 8

Write summary equations for the fermentation pathways in animal and plant / yeast cells

Answer 8

Animal cells;
Glucose—- Lactate+ energy
Plant+ yeast cells
Glucose— Carbon dioxide+ ethanol+ energy

Question 9

Compare aerobic resperation and fermentation in terms of their locations inside a cell

Answer 9

All respiration pathways begin in the cell cytoplasm. If ocygen is present then aerobic respiration is completed in the mitochondria.
If there is no oxygen then the process of fermentation is completed in the cell cytoplasm

Question 10

State and explain the link between the energy requirement of a cell and the number of mitochondria present in that cell

Answer 10

The higher the energy requirement of a cell the greater number of mitochondria. This is because