Science 10 Cell Structures and Functions

Organelle | Found In | Structure | Function | Cell Membrane (plasma membrane) | Both | A phospholipid bilayer that contains proteins. Lipids face each other while the phosphates face away from each other. Most proteins stay with the outer layer of phospholipids. | Protective barrier. Transports required materials and wastes in and out of the cell. Cell communication. | Nucleus | Both | Dense sphere inside the cell. Surrounded by a nuclear envelope with nuclear pores that allow for material transportation. | Stores DNA and direct all cellular activities. | Nucleolus | Both | Dense sphere within the nucleus. | Makes ribosomes. | Cytoplasm | Both | Gelatin-like fluid that surrounds the organelles within the membrane. | Carries required nutrients like salts, minerals and organic molecules. Cytoplasmic streaming. | Cytoskeleton | Both | Network of thin fibres made of microtubules (hollow tubes) and microfilaments (threads made of protein actin). | Support system for organelles. Maintains the shape of the cell. | Vacuoles | Both | Plants have a large central vacuole. Animal cells have smaller ones. | Used to store nutrients and water in the cell. | Vesicles | Both | Similar structure to a vacuole. | Transports materials throughout a cell. | Rough Endoplasmic Reticulum (rER) | Both | Network of membrane tubes which branch from the nuclear envelope. Covered in ribosomes. More prominent in cells that make large amounts to be exported from the cell, or inserted into the cell membrane. | Makes proteins. | Smooth ER (sER) | Both | Same as above. Not covered in ribosomes. | Involved in the synthesis of lipids and breakdown of toxic substances. | Ribosomes | Both | Consist of two sub units – a small and a large one. Some are attached to the ER while others float in the cytoplasm freely. | Location of protein synthesis. | Lysosomes | Both | Membrane-bound sacs. | Digestive functions. Breaks down food particles, invading bacteria, worn-out parts of cells. |