General BiologyTHE CELL P.BellerHistory 1665. Robert Hooke1674. Anton van Leeuwenenhoek1838. Schleiden. Plants-cells1839. Schwann. Animals- cells1855. Virchow. All cells come from existing cells.Organelles: Perform cellular functions.Cell membrane: Regulates what enters and leaves the cell “Mosaic model” double bi- layer of phospholipids, embedded proteins and attached carbohydrates.Diffusion and Osmosis:Molecules like alcohol, water, small lipidsFacilitated Diffusion:Some Ions, Glucose, saltsActive transport:(energy required) Sodium –Potassium pump Na (out) K (in)Movementof the cell membrane: Phagocytosis, Exocytosis, PynocytosisNucleus:Controls most cell processes and contains hereditary information (DNA)Chromatin: DNA (in its uncoiled form) + proteins (histones)Nucleolus:sites of assembly of ribosomesNuclear envelope:double membrane layers with many poresCytoskeleton:network of protein microfilaments that helps the cell maintain its shape; flexible framework that also supports organelles in the cell. It is also involved in many
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