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54 Cards in this Set
- Front
- Back
Fluid mosaic model diagram |
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Hydrophilic |
Describes a molecule that is water loving. The polar phosphate heads of the Phospholipid is hydrophilic and charged. |
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Hydrophobic |
Describes a molecules that is water hating. The inside nonpolar tail of the Phospholipid bilayer of the cell membrane is hydrophobic and not charged. |
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Fluid mosaic model |
Theory used to describe the structure of the plasma membrane. It is fluid as phospholipid bilayer is constantly moving. It is a mosaic because the proteins are scattered in a patchy arrangement.
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Plasma Membrane
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Outer barrier of an animal cell. Inner barrier of a plant cell. Controls the transport of molecules into and out of the cell. It is both porous and fluid. |
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Phospholipid Bilayer |
The main component of the cell membrane. There are two opposing layers of phospholipid molecules. |
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Phospholipid |
Molecule consisting of a hydrophilic head (phosphoric acid called phosphorylated alcohol and Glycerol), which forms the outer part of the membrane and a hydrophobic tail (two strings of hydrogen and carbon atoms called fatty acid chains) which forms the inner part of the cell membrane. |
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Phospholipid Structure |
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Glycoprotein |
Membrane surface protein that has carbohydrate addition. Often these a used as cell surface markers called antigens. (cell identity markers) |
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Receptor Proteins
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Membrane surface proteins that act as receivers for hormones or antibodies. |
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Channel Protein |
Transmembrane protein that makes the cell membrane porous and allows the movement of substances across the membrane. |
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Integral Protein |
Transmembrane protein that has a supporting function. |
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Cell membrane consists of |
* Phospholipds (polar hydrophilic head and nonpoalr hydrophobic fatty acids tail) * Chlolesterol (maintain the fluidity) * Proteins (integral or transmembrane, peripheral and inter membrane or lipid bound) * Carbohydrates (glyco- glycolipids or glycoproteins) |
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Fluidity of Membranes |
• Membrane molecules are held in place by relatively weak hydrophobic interactions. |
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Movement across membrane |
- move freely (water, carbon dioxide, smmonis, oxygen)
- carrier proteins transport some molucules |
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Membrane proteins |
- channels or transporters (move molecules in one direction) - receptors (recognize certain chemicals) - glycoproteins (identify cell type) - enzymes (catalyze production of substances) |
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Functions of cell membrane |
* regulates passage of substances in and out of cell * detects chemical messengers arriving at surface * link adjacent cells together by membrane junctions * anchor cells to extracellular matrix |
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Functions of membrane proteins |
* transport * enzymatic activity * signal transduction * cell-cell recognition * intercellular joining * attachment to cytoskeleton and ECM (extracellular matrix) |
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plasma membrane proteins function diagram |
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Passive transport - No energy |
* simple diffusion * dialysis - selective diffusion of solutes (Lipid-soluble materials, small molecules that can pass through membrane pores unassisted) * osmosis - water from low solute concentration to high solute concentration * facilitated diffusion - substances require a protein carrier for passive transport |
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Solution |
homogeneous mixture of two or
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Simple Diffusion |
• The net movement of a substance from an area of higher concentration to an area of lower concentration - down a concentration gradient |
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Osmotic Pressure |
• Osmotic pressure of a solution is the |
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Tonicity |
• If 2 solutions have equal [solutes], they are called isotonic |
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Tonicity diagram |
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Osmosis |
Osmosis is the diffusion of water across a |
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Facilitated Diffusion |
Diffusion of solutes with the help of special transport proteins large polar molecules and ions that cannot pass through membrane |
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Characteristics of Facilitated Diffusion |
• Specific – each channel or carrier |
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Active Transport |
Uses energy (from ATP) to move a |
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Sodium-potassium Pump |
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Coupled transport |
– Carrier protein uses ATP to move a substance across the membrane against its concentration gradient. Storing energy. |
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Coupled transport diagram |
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Passive And Active Transport Compared |
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Bulk Transport |
• Allows small particles, or groups of |
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Endocytosis |
The plasma membrane envelops small |
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Endocytosis diagram |
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Process of Phagocytosis |
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Receptor-mediated Endocytosis process |
Embedded in the membrane are proteins with specific receptor sites exposed to the extracellular fluid. The receptor proteins are usually already clustered in regions of the membrane called coated pits, which are |
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Receptor-mediated Endocytosis diagram |
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Exocytosis |
• Vesicle moves to cell surface |
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Exocytosis diagram |
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Intercellular Communication |
• Coordinates organ systems * Gap junctions * Direct linkage of surface markers |
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Chemical Communication |
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Four types of chemical messengers |
– Paracrines • Local chemical messengers • Exert effect only on neighboring cells in immediate environment of secretion site – Neurotransmitters • Short-range chemical messengers • Diffuse across narrow space to act locally on adjoining target cell (another neuron, a muscle, or a gland) – Hormones • Long-range messengers • Secreted into blood by endocrine glands in response to appropriate signal • Exert effect on target cells some distance away from release site |
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Paracrine secretion |
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Neurotransmitter secretion |
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Hormonal secretion |
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Chemical Messengers |
• Cell responses brought about primarily by signal transduction – Incoming signals conveyed to target cell’s interior |
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Chemical Messengers diagram |
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Receptor-enzyme: Tyrosine kinase pathway |
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Hormones |
• Endocrinology – Study of homeostatic activities accomplished |
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Molecules in second messenger system |
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Mechanism of hydrophilic |
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Comparison of Nervous System and |
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