B9 Respiration

Question 1

Explain why breathing rate increases during exercise

Answer 1

• When you exercise you use more energy
• To get more energy, the rate of respiration has to increase
• As rate of respiration increases there needs to be more oxygen coming into the body

Question 2

What is anaerobic respiration?

Answer 2

Breakdown of glucose to release small amount of energy without the use of oxygen

Question 3

Name the toxic substance produced by anaerobic respiration

Answer 3

Lactic acid

Question 4

What happens to the glycogen stored in muscles when you exercise?

Answer 4

Converted into glucose for respiration

Question 5

Is respiration exothermic or endothermic?

Answer 5

Exothermic

Question 6

What do plants make in anaerobic respiration?

Answer 6

Ethanol and carbon dioxide

Question 7

What is metabolism?

Answer 7

The sum of all the reactions in the body

Question 8

Examples of metabolic reactions

Answer 8

• Respiration
• Photosynthesis
• Conversion of glucose to starch, glycogen, and cellulose
• Formation of lipid molecules
• The use of glucose and nitrate ions to form amino acids, which are used to synthesise proteins
• Breakdown of excess proteins to form urea

Question 9

The role of the liver

Answer 9

• Detoxifying poisonous substances such as ethanol from alcoholic drinks
• Passing the breakdown products into the blood so they can be excreted in the urine via the kidneys
• Breaking down old, worn out blood cells and storing the iron until it is needed to synthesis more blood cells
• Removing lactic acid, convert it back to glucose

Question 10

Why is anaerobic respiration less effective than aerobic respiration?

Answer 10

In anaerobic respiration glucose is not completely broken down, so less energy is transferred

Question 11

Why can anaerobic respiration lead to muscle fatigue?

Answer 11

Build up of lactic acid in muscles prevents efficient contraction

Question 12

What is an oxygen debt?

Answer 12

The amount of oxygen needed to convert lactic acid back into glucose after anaerobic respiration

Question 13

What is fermentation?

Answer 13

A type of anaerobic respiration that occurs in yeast cells

Question 14

What is the equation for fermentation?

Answer 14

Glucose –> ethanol + carbon dioxide (+energy)

Question 15

What are the differences between anaerobic and aerobic respiration?

Answer 15

• Aerobic respiration requires oxygen, aerobic does not
• Aerobic respiration produces carbon dioxide and water, anaerobic respiration produces ethanol and carbon dioxide or lactic acid
• Aerobic respiration releases less energy than aerobic

Question 16

Explain why breathing rate increases during exercise

Answer 16

• When you exercise, you use more energy
• To get more energy, the rate of respiration has to increase
• As the rate of respiration increases, there needs to be more oxygen coming into the body
• There will also be more carbon dioxide which needs to be removed from the body
• The lungs helps this process by bringing in more air every minute so the body can get the oxygen that it needs and get rid of the carbon dioxide waste
• Therefore breathing rate increases

Question 17

What changes take place when muscular activity increases in the body?

Answer 17

• Heart rate increases and arteries dilate, increases flow of oxygenated blood to the muscles
• Breathing rate increases and breathing is deeper, increases the rate of gaseous exchange
• Stored glycogen is converted back into glucose to supply the cells with fuel for increased cellular respiration