Презентация Cell membrane Жасуша мембранасы

Shakarim State university of Semey Cell membranePrepared by the: Toleu A.SGroup: E-623Checked by: Sapakhova Z.B The cell membrane (also known as the plasma membrane or cytoplasmic membrane) is abiological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells The basic function of the cell membrane is to protect the cell from its surroundings. Structure of the Cell Membrane Membrane structure Phospholipid bilayer (nonpolar)Membrane proteins: act as transport channelsCarbohydrate chainsCholesterol Phospoholipid LayerThe first layer of the cell membrane consists of a phosphid bilayer. The phosphate molecules are arranged in such a way that the hydrophilic heads are on the outside, while the hydrophobic fatty acid tails are on the inside, facing each other.  Integral Membrane ProteinsIntegral membrane proteins are those proteins that are a part of the cell membrane structure. They are present between consecutive molecules of phopholipids. These fibrous proteins present may span the entire length of the cell membrane. These molecules have important functions, as they serve as receptors for the cell. Some of the proteins of the cell membrane may also enter the cell. Function of the cell membrane FunctionThe cell membrane (or plasma membrane or plasmalemma) surrounds the cytoplasm of living cells,physically separating the intracellular components from the extracelluar environment. Fungi, bacteria and plants have a cell wall in addition, which provides a mechanical support to the cell and precludes the passage of larger molecules. The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix and other cells to hold them together to form tissues. Membrane proteins There are two types of proteins • Integral proteins – Embedded in membrane via hydrophobic interactions with lipids. • Peripheral proteins – Located on cytoplasmic surface of lipid bilayer, constitute membrane skeleton. – Anchored via integral proteins – Responsible for membrane elasticity and stability , Cholesterol and Phospholipids Cholesterol – it is found in the cell membranes of animals but not plants. It affects the fluidity of the membrane.Phospholipids have the ability to move laterally but only upon a rare occasion are able to make a 180⁰ turn.  Phospholipids have hydrophilic heads and hydrophobic tails