HomeostasisIB MYP Biology: Subtopic test

1. 1
   A cyclist is racing up a mountain road in Colombia. At dawn the air is cold, but by midday it is hot and she is working hard. Throughout the race her core body temperature stays close to 37 °C.

   (a)

   What is the name for keeping the internal conditions of the body, such as temperature, constant?

   [1 mark]

   • AExcretion
   • BRespiration
   • CMetabolism
   • DHomeostasis

   (b)

   In the cold early morning, which response helps her keep her core temperature constant?

   [1 mark]

   • AShivering, which releases heat from muscle contractions
   • BSweating, which cools the skin
   • CVasodilation, which lets more heat escape from the skin
   • DReleasing less heat from respiration in her muscles

   (c)

   Explain how vasodilation helps to cool her at midday.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   After eating a large bowl of rice, a student's blood glucose concentration rises above its normal level. Several hours later, without any more food, it begins to fall below normal.

   (a)

   Which hormone does the pancreas release when blood glucose concentration rises above normal?

   [1 mark]

   • AGlucagon
   • BInsulin
   • CGlycogen
   • DAmylase

   (b)

   Several hours later glucagon is released. What does glucagon cause the liver to do?

   [1 mark]

   • AConvert glucose to glycogen
   • BMake more insulin
   • CConvert glycogen to glucose and release it into the blood
   • DMake more urea

   (c)

   Explain why the control of blood glucose is an example of negative feedback.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A clinic compares the blood glucose concentration of a healthy person with that of a patient who has type 1 diabetes and has not yet been treated. Each person drinks a sugary drink, and their blood glucose is measured before the drink and again after one hour and after two hours. The healthy person has 5.0 mmol dm⁻³ before the drink, 7.5 mmol dm⁻³ after one hour and 5.2 mmol dm⁻³ after two hours. The patient has 9.0 mmol dm⁻³ before the drink, 15.0 mmol dm⁻³ after one hour and 14.5 mmol dm⁻³ after two hours.

   (a)

   Describe three differences between the results for the healthy person and the patient.

   [3 marks]

   (b)

   Explain the patient's results, state how this condition is treated, and suggest one weakness of comparing only these two people.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   In one Gulf country, the number of adults with type 2 diabetes has risen sharply over twenty years. The health ministry is considering a tax on sugary drinks, which would raise their price. It plans to spend the money raised on health education in schools.

   (a)

   Explain how the body normally controls blood glucose concentration, and how type 1 and type 2 diabetes differ.

   [6 marks]

   (b)

   Discuss and evaluate the proposal to tax sugary drinks as a way of reducing type 2 diabetes.

   [6 marks]

   Total for question 4: 12 marks

End of questions