animal coordination, control and homeostasis sample exam questions and answers

Question 1

Which part of the brain contains the thermoregulatory centre? [1 mark]

Answer 1

hypothalamus

Question 2

What’s the name of the process that controls water levels in the body? [1 mark]

Answer 2

Osmoregulation

Question 3

Shivering is one way in which humans can regulate their body temperature.

Explain how shivering helps to regulate body temperature. [2 marks]

Answer 3

Marks will be given from the following:

• shivering stops the body temperature falling when external temperature drops (1 mark)
• because increased muscle contraction (1 mark)
• generates heat via respiration/friction (1 mark)

Question 4

The kangaroo rat lives in the desert.

The tubes in its kidney nephrons are much longer than most mammals.

Explain why this adaptation is beneficial to the kangaroo rat. [2 marks]

Answer 4

An explanation linking three of the following:

• the kangaroo rat lives in dry conditions so it needs to retain as much water as possible (1 mark)
• as most water is reabsorbed in the loop of Henle, a longer loop gives more surface area for water reabsorption (1 mark)

Question 5

Explain how the blood entering the nephron of the kangaroo rat is filtered to remove excess sodium ions and water. [3 marks]

Answer 5

An explanation linking three of the following:

• ultrafiltration occurs in the glomerulus where the liquid part of the blood passes into the Bowman’s capsule (1 mark)
• reabsorption of some water and sodium ions takes place as it travels through the nephron (1 mark)
• excess water and sodium ions form urine (1 mark)

Question 6

Research shows that overweight people may develop type 2 diabetes.

Body Mass Index (BMI) can be used to identify people who are overweight. BMI can be calculated using the equation:
BMI=(mass in kilograms) ÷ (height in meters x height in meters)
Calculate the BMI for a person who has a mass of 77 kilograms and a height of 1.6 metres [2 marks]

Answer 6

77 ÷ (1.6 x 1.6) (1 mark)

= 30 (1 mark)

Accept two marks for correct answer.

Accept the 30.07 to 30.08, or 30.1.

Question 7

The doctor diagnosed a person with an underactive thyroid gland.

Explain why an underactive thyroid could cause this patient to feel tired and have an increased body mass. [6 marks]

Answer 7

• the thyroid gland produces thyroxine (1 mark)
• thyroxine helps to regulate metabolic rate (1 mark)
• an underactive thyroid would cause less thyroxine to be produced (1 mark)
• metabolic rate drops (1 mark)
• they feel tired because less energy being released from food (1 mark)
• more fat storage so the person gains body mass (1 mark)