Skip to content

Course home

Question bank·3.3 Maintaining internal environments
Sign up

3.3 Maintaining internal environments

EasyMediumHard
1234567891011121314151617181920212223242526272829303132333435363738
Question 2
F

A student investigates the effect of salt solutions on red blood cells.

  • She puts one drop of blood into each of three tubes, X, Y and Z.
  • Each tube contains a salt solution of a different concentration.
  • After 10 minutes, she looks at a sample from each tube using a light microscope.

The Table shows her results.

Table

TubeConcentration of salt solution in %\%%Appearance of red blood cells
X0.0no red blood cells seen
Y0.9normal shape
Z3.0shrunken and wrinkled
a.

The concentration of salt in blood plasma is about 0.9%.

Explain why the red blood cells in tube Y do not change shape.

[2]
b.

Explain why no red blood cells are seen in tube X.

[3]
c.

Identify one variable the student should control in this investigation.

[1]
d.

Patients in hospital are sometimes given fluid through a drip into a vein.

Suggest why this fluid must have the same concentration of salt as blood plasma.

[2]
Markscheme

3.3 Maintaining internal environments Questions

  1. GCSE
  2. /Biology
  3. /3.3 Maintaining internal environments

72 exam-style questions on OCR GCSE Biology 3.3 Maintaining internal environments, covering 3.3.1 Importance of a constant internal environment, 3.3.2 The skin and body temperature, 3.3.3 Insulin and blood sugar, 3.3.4 Glucagon and blood sugar, 3.3.5 Type 1 and type 2 diabetes, 3.3.6 Osmotic changes in body fluids, 3.3.7 Kidneys and water balance, 3.3.8 Structure of the kidney and tubule, 3.3.9 ADH and kidney tubule permeability, and 3.3.10 Responses to temperature and osmotic challenges. Each one has a worked solution and a mark scheme showing where the marks go.

More questions