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Year 7

Diffusion through the cell membrane

I can explain why some substances can diffuse through the cell membrane and others cannot.

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New
New
Year 7

Diffusion through the cell membrane

I can explain why some substances can diffuse through the cell membrane and others cannot.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. All substances, including the cell cytoplasm and substances within it, are made up of particles.
  2. Particles of some substances diffuse into and out of a cell by moving through small holes in the cell membrane.
  3. The particles that make up some substances are too big to diffuse through the holes in the cell membrane.
  4. The cell membrane is selectively-permeable because only some substances can diffuse through it.
  5. The net movement of particles through a cell membrane is down a concentration gradient.

Common misconception

Thinking that all, or no, substances can diffuse through the cell membrane. Thinking that cells choose to take in particular substances, or that cells breathe or suck in substances such as oxygen.

The lesson explores the idea that particles of some, but not all, substances are small enough to diffuse through holes in the selectively-permeable cell membrane.

Keywords

  • Cell membrane - All cells are surrounded by a membrane that controls what can enter and leave the cell.

  • Particles - All substances are made up of particles that are too small for us to see.

  • Diffusion - Diffusion is the net movement of particles of a substance down a concentration gradient.

  • Selectively-permeable - A material is selectively-permeable if some substances can move through it but others cannot.

  • Net movement - Net movement is the overall movement of particles from one area to another.

In Task A, students could be allowed to choose from a collection of objects which one they think is the best model of a cell membrane, or be asked to come up with their own suggestions and then peer assess their objects.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
All animals are made up of tiny living building blocks called .
An image in a quiz
Correct Answer: cells
Q2.
Which organisms are made up of cells?
only animals
only animals and plants
only animals, plants and fungi
Correct answer: all organisms
Q3.
What is the name of the structure labelled A in the diagram of an animal cell?
An image in a quiz
Correct Answer: cell membrane, membrane
Q4.
Which diagram best represents the particles that make up the cell cytoplasm?
diagram A
Correct answer: diagram B
diagram C
Q5.
The particles of oxygen will move through the cell cytoplasm due to the process of ...
An image in a quiz
concentration.
Correct answer: diffusion.
gradient.
solution.
Q6.
Which diagram is labelled correctly?
diagram A: net movement is up a concentration gradient from low to high
Correct answer: diagram B: net movement is down a concentration gradient from high to low
diagram C: net movement is against a concentration gradient from low to high
diagram D: no concentration gradient and no net movement
Q3 UYSEG

Exit quiz

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6 Questions

Q1.
Which of these are features of the cell membrane?
An image in a quiz
Correct answer: controls what can enter and leave the cell
is where cellular respiration takes place
is where substances are stored
makes the cell’s food
Correct answer: surrounds the cell cytoplasm
Q2.
Which statement about the cell membrane is true?
An image in a quiz
It has no holes in it.
It has large holes in it.
Correct answer: It has small holes in it.
Q3.
Who has the correct idea about the cell membrane?
An image in a quiz
Aisha: “Particles of all substances can move through the holes in the membrane.”
Alex: “Only large particles can move through the holes in the membrane.”
Correct answer: Jacob: “Only small particles can move through the holes in the membrane.”
Sofia: “No particles can move through the holes in the membrane.”
Q4.
Which type of particle will not move through the holes in the cell membrane?
An image in a quiz
particle A
particle B
Correct answer: particle C
Q5.
The cell membrane is described as a -permeable membrane.
Correct Answer: selectively, partially, semi
Q6.
Which statement is true?
An image in a quiz
Correct answer: Net movement of particles of carbon dioxide will be from the inside to outside.
Particles of carbon dioxide cannot diffuse through the cell membrane.
Particles of carbon dioxide will diffuse up the concentration gradient.
The concentration of particles of carbon dioxide is higher outside the cell.
There is no concentration gradient across the cell membrane.