The Anatomy and Physiology of Animals/Diffusion and Osmosis Worksheet 1

Chapter 3 The Cell

1. List 5 mechanisms by which molecules pass through the plasma membrane.

State whether these mechanisms are passive or active (ie use energy or not).

Mechanism for crossing plasma membrane	Passive or Active?
1.	?
2.	?
3.	?
4.	?
5.	?

2. Which mechanism:

a.) uses no energy and results in an even distribution of molecules?

b) uses no energy, and occurs across a semi-permeable membrane?

c) occurs across the membrane of red blood cells causing them to swell and burst when placed in distilled water?

d) uses energy and allows the cell to take into itself particles and bacteria?

e) moves substances across the plasma membrane from a low to a high concentration?

f) uses a carrier molecule to help substances across a membrane but does not require energy?

3. Circle the correct statements below.

Diffusion is a process that:

a) occurs in liquid and gases

b) only occurs in liquids

c) uses energy

d) uses no energy

e) occurs naturally

f) occurs from a lower concentration of molecules to a higher concentration

g) occurs from a higher concentration of molecules to a lower one

h) results in an even distribution of molecules

i) only occurs with small molecules like water

j) is more rapid at low temperatures

k) is more rapid at high temperatures

4. Circle the correct statements below.

Osmosis:

a) is a special kind of diffusion

b) only occurs in gases

c) is not a natural process

d) is the diffusion of water molecules only

e) is the diffusion of water molecules from a high concentration of water to a low concentration of water

f) requires a semi-permeable membrane

g) requires energy

h) results in an even dispersal of water molecules

i) results in an even distribution of salt molecules

5. A semi-permeable membrane is a membrane that:

a) allows some molecules to go through but not others

b) allows all molecules to go through

c) is different on each side

d) is partly made from permeable compounds

6. Active transport:

a) uses energy

b) uses no energy

c) occurs from a lower concentration of molecules to a higher concentration

d) occurs from a higher concentration of molecules to a lower one

e) results in an even distribution of molecules

f) only occurs with small molecules like water

7. Oxygen crosses the plasma membrane by:

a) diffusion via the channels

b) active transport

c) diffusion through the lipid bilayer

d) facilitated diffusion

e) osmosis

8. Water crosses the plasma membrane by:

a) diffusion via the channels

b) active transport

c) diffusion through the lipid bilayer

d) facilitated diffusion

e) osmosis

9. Lipid soluble molecules cross the plasma membrane by:

a) diffusion via the channels

b) active transport

c) diffusion through the lipid bilayer

d) facilitated diffusion

e) osmosis

f) pinocytosis

g) phagocytosis

10 Sodium ions move from a low to a high concentration across the plasma membrane by:

a) diffusion via the channels

b) active transport

c) diffusion through the lipid bilayer

d) facilitated diffusion

e) osmosis

f) pinocytosis

g) phagocytosis

11 Glucose molecules cross the plasma membrane by:

a) diffusion via the channels

b) active transport

c) diffusion through the lipid bilayer

d) facilitated diffusion

e) osmosis

f) pinocytosis

g) phagocytosis

Worksheet Answers