B9 - Respiration

Question 1

State the word equation for aerobic respiration.

Answer 1

glucose + oxygen > carbon dioxide + water + energy

Question 2

List ways in which living organisms use energy

Answer 2

survive, grow, reproduce

Question 3

Write the balanced symbol equation for respiration

Answer 3

C6H12O6 + 6O2 🠮 6CO2 + 6H2O + ATP

Question 4

How is respiration an exothermic reaction?

Answer 4

Respiration is an exothermic process as it releases heat or energy.

Question 5

Describe how heart rate, breathing rate, and breath volume change with exercise.

Answer 5

heart rate increases as you have to pump more blood around body.
breathing rate increases as you have to get more oxygen in and co2 out
breath volume changes to make sure more oxygen is absorbed into blood.

Question 6

Why do stores of glycogen change with exercise?

Answer 6

glycogen reserves in the muscles become low as more glucose is used for respiration, and additional glucose is transported from the liver.

Question 7

State the word equation for anaerobic respiration in animals, plants, and microorganisms.

Answer 7

glucose 🠮 lactic acid + energy

Question 8

Describe why cells respire anaerobically.

Answer 8

When there is a shortage of oxygen, muscles respire anerobically.

Question 9

Give some uses of fermentation

Answer 9

ethanol, alcoholic beverages, bread, yogurt

Question 10

Write the balanced symbol equation for anaerobic respiration in plants and microorganisms

Answer 10

glucose + enzymes 🠮 carbon dioxide + lactic acid

Question 11

Compare and contrast aerobic and anaerobic respiration.

Answer 11

Anaerobic:
Releases less energy than aerobic
Does not require oxygen
Involves breakdown of glucose
lactic acid produced
Aerobic:
glucose broken down in presence of oxygen to produce water and carbon dioxide
happens in mitochondria
releases more energy than anaerobic

Aerobic respiration is far more energy-efficient than anaerobic respiration.

Question 12

Explain why muscles get tired during exercise.

Answer 12

During long periods of vigorous activity:
lactic acid levels build-up
glycogen reserves in muscles become low as more glucose is used for respiration, and additional glucose is transported from the liver.
This build-up of lactic acid produces an oxygen debt.

As body stores of glycogen become low, the person suffers from muscle fatigue.

Question 13

define metabolism.

Answer 13

sum of all reactions on a cell or the body.

Question 14

list some metabolic reactions

Answer 14

‘building up’ (anabolism) and ‘breaking down’ (catabolism)

Question 15

describe the role of the liver in repaying oxygen debt.

Answer 15

When oxygen is available again lactic acid is oxidized in the liver, thus repaying the debt.

Question 16

explain the link between protein consumption and concentration of urea in urine

Answer 16

Urea is a major nitrogenous waste product of protein metabolism. High-protein diet increases the urea concentration in urine, which makes us explore whether the continuous high urea stimulation could damage the urothelium and then increase the risk of carcinogenesis

Question 17

Pre test - Compare the similarities and differences between anaerobic respiration in animal and yeast cells (6 marks)

Answer 17

•Both break down glucose
•Both do not require energy
•Both produce ATP/energy
•Animals produce lactic acid, yeast produces carbon dioxide and ethanol
Glucose > lactic acid + energy - animals
glucose > ethanol + co2 + energy - plants and yeast

Question 18

Give a function of the liver

Answer 18

Detoxifies poisonous substances from the blood - e.g ethanol and alcohol.