2.1: What is a Cell?
> Basic unit (the smallest parts) of a living things.
> Can only be seen through a microscope
Nucleus: Controls cell activities, contains genetic information
Cell membrane: Controls the substances that move in and out of the cell
Cytoplasm: Dissolves food particles through chemical process
Cell wall: Maintains the shape of the plant cell
Vacuole: Stores sugar solution and mineral salts
Chloroplast: Contains chlorophyll that is needed for photosynthesis
2.2: Unicellular Organisms and Multicellular Organisms
*Unicellular organisms
>Consist of only one cell, usually are microorganisms.
> Can only be seen under microscope.
> Live in water or wet places.
> E.g. Amoeba, Euglena, Paramecium, yeast.
*Multicellular organisms
> Consist of many cells.
> E.g. hydra, spirogyra, mucor.
> Humans are the most complex multicellular organisms.
2.3: Cell Organisation in the Human Body
 |
| click for enlargement |
2.4: The Human Being – A Complex Organism
> Humans are complex organisms
> Human body is made up of millions of cells
> The cells are specialised to perform certain functions
