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The alveoli in the lungs have a surface area equivalent to a tennis court!

Unit 2 - Diffusion

This GCSE Biology quiz tests your understanding of diffusion, the movement of particles from higher concentration to lower concentration in cells, lungs and different parts of the body.

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(quiz starts below)

Fascinating Fact:

Oxygen diffuses from the air in the lungs into the blood, and from the blood into body cells, where it is used in respiration.

In GCSE Biology, diffusion is studied as a key method of transport in living organisms. You learn how particles move down a concentration gradient in the lungs, gut, and individual cells, and why thin surfaces and good blood supply make diffusion faster.

Key Terms

Diffusion: The net movement of particles from an area of higher concentration to an area of lower concentration.
Concentration gradient: The difference in concentration between two areas that drives diffusion.
Partially permeable membrane: A barrier that allows some particles to pass through but not others.

Frequently Asked Questions (Click to see answers)

What is diffusion in GCSE Biology?

In GCSE Biology, diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration, down a concentration gradient, without using energy.

Where does diffusion happen in the human body?

Diffusion happens in many places, including gas exchange surfaces in the lungs, dissolved food moving from the small intestine into the blood, and substances moving into and out of individual cells.

How is diffusion different from osmosis and active transport?

Diffusion is the movement of any particles down a concentration gradient. Osmosis is diffusion of water through a partially permeable membrane, while active transport uses energy to move substances against a concentration gradient.

Try These Related Quizzes

1 .

The rate of diffusion is increased in which of the following situations?

If there are fewer molecules

If the surface area is increased

If the temperature is decreased

If the diffusion distance is greater

More molecules can pass through the membrane at the same time

2 .

Active transport is where molecules use a carrier and are moved...

with the concentration gradient

along the concentration gradient

against the concentration gradient

equally to the concentration gradient

Molecules, such as amino acids and glucose, are moved into and out of cells using active transport. This is an active process requiring energy and a carrier

3 .

Which of these is a major site for gaseous exchange in the body?

Kidney tubule

Alveolus

Heart

Aorta

The plural is alveoli

4 .

Diffusion is...

active

inactive

passive

impassive

This means that it happens automatically, without the need for anything to cause it to happen

5 .

Diffusion is the movement of particles from high concentration to which of the following?

Higher concentration

Lower concentration

Equal concentration

High concentration

The difference in concentration either side of a semi or fully permeable membrane is the concentration gradient

6 .

Which of these molecules only moves by simple diffusion?

Water

Glucose

Cholesterol

Carbon dioxide

Small molecules diffuse more easily and more rapidly than larger molecules

7 .

Diffusion requires which of the following?

Energy

No energy

Glucose

Insulin

That is because it is a passive process

8 .

Diffusion is fast in the lungs. Why is this?

Because the lungs have a huge area

Because the lungs have a huge surface area

Because the lungs have a huge volume

Because the lungs have a huge density

The alveoli in the lungs have a surface area equivalent to the area a tennis court!

9 .

Diffusion happens faster in which of the following situations?

If the difference in concentration is bigger

If the difference in concentration is smaller

If the difference in concentration is the same

The difference in concentration makes no difference to the rate of diffusion

The bigger the difference in concentration, the faster the rate of diffusion

10 .

Which of these molecules is too big to diffuse through a membrane, using simple diffusion?

Starch

Oxygen

Carbon dioxide

Water

If a molecule cannot fit through the holes in the cell membrane, it cannot pass into or out of a cell. Some large molecules, like proteins, have to be broken down before a cell can take them in

You can find more about this topic by visiting BBC Bitesize - Diffusion (CCEA)

Author: Donna Davidson (GCSE Biology Teacher & Examiner, Quiz Writer)