Cells All living things are made of cells. Some living things (organisms) are made up of only one cell. Like bacteria. BACTERIA Bacteria are generally small cells, they are also simple. They are made up of a cell wall, cytoplasm, cell membrane and sometimes flagellum (to help them swim). CELL WALL = This is a ridged (hard) outer layer that protects the cell and allows it to keep a particular shape. CELL MEMBRANE = This is a semi-permeable substance. This means it allows some things to pass through, but other things can not pass through. For example, water can fit through the small holes, but bigger things such as salt can not fit through. Cell membrane acts as a guard, deciding which substances can enter and leave the cell. CYTOPLASM = This is a jelly like substance that fills up the space left over in a cell. New substances are made and energy is released and stored here. ANIMALS Animal cells are made up of mitochondria, endoplasmic reticulum, cell membrane, cytoplasm, golgi apparatus, nucleus and vacuoles. MITOCHONDRIA – These are very small organelles. They make energy for the cell. It uses chemical reactions that release energy to power all the things a cell needs to do. ENDOPLASMIC RETICULUM – This is a series of tubes that is used to transport materials around the cell. NUCLEUS – This is a large rounded object in the centre of the cell that houses the DNA. GOLGI APPARATUS – Used for transport, they can ‘package’ chemicals and send around the cell. VACUOLE – These are storage areas that contain water, air, food particles and waste. PLANTS Plant cells are usually large. They contain chloroplast, cell wall, a large central vacuole, mitochondrion, cell membrane and nucleus. CHLOROPLAST – These are green coloured organelles. They contain the chemical chlorophyll, which uses sunlight to make energy in the process of photosynthesis.