Introduction

Animals and plants are made of cells. Cells form the basic "building blocks" for living things. Some cells have specialised functions.

Tissues are made from cells of a similar type. Organs are made from tissues, and systems are made from several organs working together.

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Cells

Cells are very small. They are the basic building blocks of all animals and plants. These photographs show cells seen through a microscope.

Animal cells and plant cells both contain:

Cell membrane, cytoplasm, nucleus

Plant cells also contain these parts, not found in animal cells:

Chloroplasts, vacuole, cell wall

The table summarises the functions of these parts. 

Animal cells usually have an irregular shape, and plant cells usually have a regular shape.

Cells are made up of different parts. It is easier to explain what these parts are by using diagrams like the ones below.

Animal cells and plant cells can form tissues, like muscle tissue. A living tissue is made from a group of cells with a similar structure and function, which all work together to do a particular job.

 An organ system is made from a group of different organs, which all work together to do a particular job. 

circulatory system

respiratory system

digestive system

reproductive system

leaf canopy