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17 Cards in this Set
- Front
- Back
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diffusion |
the random movement of molecules; net movement is from an area of higher concentration to an area of lower concentration
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What increases rate of diffusion? |
* increase temperature * smaller particles * steeper concentration gradient
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osmosis |
diffusion of H2O through a selectively/semi permeable membrane |
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hypertonic |
in comparing two solutions, the solution with the higher osmolarity.
example: red blood cells placed in a drop of highly concentrated salt solution can be seen to shrivel up
explanation: the concentration of the water molecules is greater in the cytoplasm of the RBCs than in the surrounding salt solution. The net movement of water molecules is outward from an area of greater concentration to an area of lesser concentration. The salt solution in this example is said to be hypertonic to the cytoplasm of the RBCs |
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hypotonic |
in comparing two solutions, the solution with the lower osmolarity.
example: red blood cells place in a drop of distilled (pure) water can be seen to swell and burst
explanation: the concentration of water molecules is greater in the distilled water than in the cytoplasm of the RBCs. Since the net result of diffusion is the movement of molecules from an area of greater concentration to an area of lesser concentration, the net movement of water molecules is across the membrane and into the RBCs. The distilled water in this example is said to be hypotonic to the cytoplasm of the RBCs. |
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isotonic |
a solution with an osmolarity that does not result in water movement across plasma membranes
example: RBCs are placed in a drop of blood plasma. No change is seen in the RBCs.
explanation: because the water concentration is the same in the blood plasma as it is in the cytoplasm of the RBCs, there is no net movement of water molecules. The number of water molecules diffusing out of the RBCs = the number diffusing into the RBCs. In this example we can say that the blood plasma is istonic to the cytoplasm of the RBC's |
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osmotic pressure |
the pressure needed to be applied on one side of a semi-permeable membrane in order to stop osmosis |
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carbohydrates - 1st preferred fuel *sugars *starch *glycogen *cellulose |
subunits *monosaccharides - glucose, fructose (simple sugar) *disaccharide - sucrose, maltose, lactose (double sugar) *polysaccharides - starch, glycogen cellulose |
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lipids - 2nd preferred fuel *fats *oils *waxes *cholesterol *steroid hormones |
subunits *fatty acids *glycerol
uses: fuel, biological membranes, phospholipids bilayer, myelin sheath |
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nucleic acids *DNA *RNA |
subunits *nucleotides *1 of 4 nitrogenous bases *phosphate group *simple sugar
DNA (deoxyribonucleic acid) - "genetic material" chemically encoded "blueprints" for PROTEINS
RNA (ribonucleic acid) mRNA - messenger RNA tRNA - transfer RNA rRNA - ribosomal RNA
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proteins |
subunits *amino acids - 20
categories *structural proteins - collagen, keratin, elastin *transport proteins - hemoglobin, sodium, potassium, and chlorine channels, sodium/glucose pump *regulatory proteins - regulate gene expression, regulate muscle contraction *storage proteins - myoglobin *hormones - peptide hormones (chemical messengers)
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enzymes - "catalytic proteins" |
allow chemical reaction to go more rapidly and at lower temperature |
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enzymes are proteins that act as catalysts ie. lower activation energy |
*enzymes do not become part of reaction they catalyze
*enzymes are unchanged when they catalyze a reaction
*enzymes have an optimal temperature and pH |
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enzymes put slight strain to break chemical bonds |
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enzymes bind to one specific substrate |
enzyme + substrate ----> enzyme-substrate complex -----> product + enzyme |
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denatured |
irreversible change in protein structure (raw egg ---> egg in frying pan)
*high temperatures *extremes in pH *strong chemicals; e.g. alcohol *radiation *electricity |
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active transport |
PUMPS things up a concentration gradient (requires use of ATP) |
