animal coordination, control and homeostasis sample exam questions and answers Flashcards
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Which part of the brain contains the thermoregulatory centre? [1 mark]
hypothalamus
What’s the name of the process that controls water levels in the body? [1 mark]
Osmoregulation
Shivering is one way in which humans can regulate their body temperature.
Explain how shivering helps to regulate body temperature. [2 marks]
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)
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]
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)
Explain how the blood entering the nephron of the kangaroo rat is filtered to remove excess sodium ions and water. [3 marks]
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)
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]
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.
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]
- 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)