HomeostasisIB MYP Biology: Flashcards

Exam questions on Homeostasis

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.
   Explain how vasodilation helps to cool her at midday.2 marks
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.
   Explain why the control of blood glucose is an example of negative feedback.2 marks
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.
   Describe three differences between the results for the healthy person and the patient.3 marks