Cells

Cells

• Cells are the building blocks of all living things.
• Living things can be classified into unicellular organisms (one cell only) or multicellular organisms (many cells).

Animals cells

• Animals cells have no cell walls.
• The structure and its function of a cell:
  -Cell membrane: control the movement of substances in and out of a cell
  -Nucleus: controls the activities of a cell and stores hereditary materials called chromosomes
  -Vacuole: stores food and nutrients
  -Cytoplasm: allows chemical reactions to take place

Plant cells

• Plant cells have cell walls.
• The structure and its function of a cell:
  -Cell membrane: control the movement of substances in and out of a cell
  -Nucleus: controls the activities of a cell and stores hereditary materials called chromosomes
  -Vacuole: stores food and nutrients
  -Cytoplasm: allows chemical reactions to take place
  -Chloroplast: contains chlorophyll to absorb sunlight for photosynthesis
  -Cell Wall: supports and maintains the shape of the cell

Division of Labour

• Division of labour in living organisms allows more efficient and smooth functioning in the multicellular organisms.
• When a group of cell perform the similar function, they are known as tissue.
• When a group of tissues perform the similar function, they are known as organ.
• When a group of organs perform the similar function, they are known as organ system.
• Various organ systems make up an organism.