Download National 5 Biology Unit 1 cell Biology – Homework 2

National 5 Biology Unit 1 cell Biology – Homework 2
Osmosis and Diffusion
Please answer all these questions on named, lined refill.
1
What is the name given to the difference in concentration of a substance on either side of a cell
membrane?
(1)
2
What is diffusion?
(1)
3
Name four substances that can leave or enter a cell by diffusion.
(4)
4
Define “osmosis”.
(1)
5
What is a selectively permeable membrane?
(1)
6
Draw a labelled diagram to show its structure.
(2)
7
Arrange the following in order of increasing water concentration:
a. Water.
b. 10% salt solution.
c. 1%salt solution.
d. 5%salt solution.
(1)
8
9
Use the terms isotonic, hypotonic and hypertonic to describe the bathing solutions (the
solution it is sitting in) of the following cells:
a. A red blood cell would burst in this solution.
b. An onion cell would stay the same shape in this solution.
c. An onion cell would show plasmolysis in this solution.
d. An onion cell would become turgid in this solution.
e. A red blood cell would stay the same shape in this solution.
f. A red blood cell would shrink in this solution.
g. An onion cell would become flaccid in this solution.
h. The vacuole of a plant cell would swell in this solution.
(8)
Explain why a plant cell does not burst when placed in pure water.
(1)
Total marks 20