Skoool Kerala

Animal Cells

All animals and plants are made up of cells.

This diagram represents an animal cell. Most cells have:

• A nucleus that controls the activities of the cell
• Cytoplasm, where most of the chemical reactions take place. The reactions are controlled by enzymes
• A cell membrane that controls what enters and leaves the cell
• Mitochondria in the cytoplasm where respiration takes place to release energy

Plant Cells

This diagram represents a plant cell. Plant cells also have:

• A cell wall made of cellulose, which strengthens the cell and provides support

They often have:

• Chloroplasts which contain the green pigment chlorophyll. This absorbs light energy for photosynthesis
• A permanent vacuole filled with cell sap, which provides support

Specialised Cells

Different types of cells look different because they are adapted to their function. They are said to be specialised.

Similar cells that carry out the same function are grouped together in tissues.

Different tissues work together in organs.

Different organs are combined together to form organ systems.

For example, muscle cells form muscle tissue. The heart contains muscle tissue, nervous tissue and connective tissue. The heart is part of the circulatory system.