The Chemistry of Lif1

The Chemistry of Lif1 - requires ATP. An exchange pump is...

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The Chemistry of Life Osmosis Osmosis is the diffusion of a solvent (water) across a selectively permeable membrane. Osmotic pressure is a measure of the tendency of water to move across the selectively permeable membrane. In a hypotonic solution, cells swell (and can undergo lysis); in an isotonic solution, cells neither swell nor shrink; and in a hypertonic solution, cells shrink and undergo crenation. Filtration Filtration is the passage of a solution through a partition in response to a pressure difference. Some materials in the solution do not pass through the partition. Mediated Transport Mechanisms Mediated transport is the movement of a substance across a membrane by means of a carrier molecule. The substances transported tend to be large, water- soluble molecules. Facilitated diffusion moves substances from a higher to a lower concentration and does not require energy in the form of ATP. Active transport can move substances from a lower to a higher concentration and
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Unformatted text preview: requires ATP. An exchange pump is an active transport mechanism that moves two substances in opposite directions across the cell membrane. • Secondary active-transport uses the power of one substance moving down its concentration gradient to move another substance into the cell. Endocytosis and Exocytosis • Endocytosis is the movement of materials into cells by the formation of a vesicle. Phagocytosis is the movement of solid material into cells by the formation of a vesicle. Pinocytosis is similar to phagocytosis, except that the material ingested is much smaller and is in solution. • Exocytosis is the secretion of materials from cells by vesicle formation. Cell Metabolism • Aerobic respiration requires oxygen and produces carbon dioxide, water, and 36 to 38 ATP molecules from a molecule of glucose. • Anaerobic respiration does not require oxygen and produces lactic acid and two ATP molecules from a molecule of glucose....
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This note was uploaded on 12/04/2011 for the course ANTHRO 2000 taught by Professor Monicaoyola during the Fall '10 term at Broward College.

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