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Cell Structure . Cell Structure . Cytoplasm Fluid material in which the cell contents are suspended 75% - 90% water Cytoskeleton framework of protein fibres Microtubules : hollow rods which keep organelles in place + move them around cell
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Cytoplasm • Fluid material in which the cell contents are suspended • 75% - 90% water • Cytoskeleton • framework of protein fibres • Microtubules: hollow rods which keep organelles in place + move them around cell • Microfilaments: (smaller) move materials around cell or move whole cell Cell Structure
Organelles • Nucleus • - Surrounded by a nuclear membrane (double membrane) with nuclear pores • Contains genetic material (DNA) • - DNA determines which enzymes (proteins) will be made by cell therefore controlling the functioning of the cell • - Nucleoluscontains RNA (protein synthesis) • - Filled with nucleoplasm • Ribosomes • small spherical structures which assist in protein production • (amino acids polypeptides / proteins) Cell Structure
Endoplasmic reticulum • - Network of channels formed by pairs of parallel membranes which connect with cell and nuclear membranes • - Provide surface for chem.. reactions and channels allow molecule storage and transport • Rough / Granular ER: Ribosomes attached • Smooth / Agranular ER: No ribosomes • Golgi Apparatus • - series of flattened membranous bags which function to modify proteins and package them for secretion • - addition of sugar, sulphate, phosphate, fatty acids • - Ends of golgi apparatus pinch off to form vesicles with proteins inside Cell Structure
Lysosomes • - small spheres bonded by a membrane from the golgi apparatus • - contain digestive enzymes (breaks down proteins, lipids, nucleic acids and some carbs) • Mitochondria • - spherical or sausage shaped structures with a double membrane (the inner one is folded) • - contains enzymes which are involved in chem. reactions which release energy • Centrioles • - pair of cylindrical structures (which are at right angles) made up of a ring of very fine tubes • - involved in cellular reproduction • Cilia / Flagella • Cilia: fine hair like projections which assist in movement along the cell membrane • Flagella: one or two longer tail like projections Cell Structure