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

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

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

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

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

Diffusion through the cell membrane

Science

Pupils will learn about absorption of small molecules from food in the digestive system.

Pupils learned about muscles and that they have roles in organ systems.

This unit explores diffusion's role in material movement in and between cells and involves making predictions, observations and measurements with various methods.

Diffusion

controls what can enter and leave the cell

is where cellular respiration takes place

Which of these are features of the cell membrane?

Which statement about the cell membrane is true?

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.”

Jacob: “Only small particles can move through the holes in the membrane.”

Sofia: “No particles can move through the holes in the membrane.”

Who has the correct idea about the cell membrane?

Which type of particle will **not** move through the holes in the cell membrane?

The cell membrane is described as a {{}}-permeable membrane.

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.

All animals are made up of tiny living building blocks called {{}}.

What is the name of the structure labelled A in the diagram of an animal cell?

Which diagram best represents the particles that make up the cell cytoplasm?

The particles of oxygen will move through the cell cytoplasm due to the process of ...

diagram A: net movement is up a concentration gradient from low to high

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

Starter Quiz