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| It encloses the cell, and prevents the contents from escaping. All substances go through the plasma membrane. These substances include ions such as potassium and sodium, which have special ion-selective channels in the membrane. |
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| The lipid bilayer is freely permeable to lipid-soluble substances such as oxygen and carbon dioxide. In contrast, the lipid bilayer is impermeable to water soluble substances such as sugars, amino acids ions. etc |
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| is a lipid that is the second determinant of membrane fluidity, and that also important in stabilizing the membrane. |
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| are found in the outer half of the bilayer. They contain monosaccharide sugars, which point outwards from the cell surface |
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| embedded in the membrane. If they span it, they are called transmembrane proteins. |
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| are bound to the surface of the membrane. |
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| Carbohydrates in plasma membrane |
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| Carbohydrates are found attached to lipids or proteins in glycolipids and glycoproteins. They may play a role in cell-cell interaction and cell recognition. |
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| Often between cells in an epithelial sheet. Tight junctions close the spaces between cells by fusing neighboring membranes. They also segregate proteins in the apical surface of an epithelium from those in the basal surface. |
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| spot-welds between adjacent cells that reinforce the tissue. Found between cells in the skin. In the disease pemphigus individuals make antibodies against the desmosomes in the skin which can cause leakage of extracellular fluid into the loosened epithelium. |
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| couple cells electrically and chemically. Important in cardiac muscle |
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| Complex network of inter-conected membranes that form flattened sacs, elongated canals and vesicles. Important for the synthesis of proteins and lipids. Rough has ribosomes, Smooth doesn't |
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| particles composed of ribosomal RNA (rRNA) and about 80 different ribosomal proteins. They play a vital role in protein synthesis, and are responsible for joining the individual amino acids together during this process. Ribosomes are assembled in the nucleolus of nucleus an move to the cell cytoplasm, where protein synthesis occurs. |
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| Proteins are first assembled in the endoplasmic reticulum, transported to the Golgi, and those that are destined for secretion are moved from there to the cell surface. The golgi is prominent in cells that specialize in the secretions of proteins. |
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| contain all the enzymes needed to produce most of the energy required by a cell.they use oxygen to oxidize glucose and fatty acids |
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| Membrane-bound organelles that contain powerful enzymes that are specialized for digestion, and can break down proteins, carbohydrates and nucleic acids. These enzymes digest foreign particles such as bacteria |
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| Membrane-bound organelles particularly abundant i liver and kidney - bags of enzymes. These enzymes breakdown fatty acids, synthesize cholesterol, and make parts of myelin sheeth that surrounds many nerve axons |
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| Is an area in the cell where microtubles are produced. |
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| present in cells around the Golgi and are involved in endocytosis and exocytosis. They may contain a variety of substances, such as hormones or neurotransmitters. |
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| Inactivation of a tumor suppressor gene causes cancer |
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| Activation of a proto-ocogene cause cancer |
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