cells as the basic unit of life

• eukaryotic cell: has membrane bound organelles, plant and animal cells and a nucleus
• prokaryotic cell: no membrane bound organelles, bacteria and no nucleus
• cell wall: extra layer on the outside of the cell membrane, gives plant cell support and stability, contains cellulose to help keep shape
• mitochondria, chloroplasts and vacuoles make up cytoplasm
• mitochondria is surrounded by a double membrane, combines with oxygen and food molecules releasing energy process is called respiration
• chloroplasts and only present in plant and algae cell, contains chlorophyll which enables photosynthesis
• vacuoles are present in plant cells and are filled with cell sap, sometimes present in animal cells but are smaller
• the nucleus is in plant and animal cells, contains cells DNA molecules and controls the cell's activities
• nuclear membrane is a double membrane that surrounds the nucleus of a cell, porous for substances to pass through, nucleolus is inside the nucleus
• what does the nucleus do?

  control and direct the cell’s activity
• rough ER has ribosomes on its surface, smooth ER does not have any ribosomes
• endoplasmic reticulum (ER) is a network of flattened sacs and tubes made up of protein-coated membranes, it makes lipid and protein molecules
• golgi apparatus modifies proteins produced by the endoplasmic reticulum, packages them into vesicles which then move out of the golgi
• lysosome contain digestive enzymes, they break down waste materials and old organelles within the cell
• ribosomes synthezise protein in the cytoplasm of the cell