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44 Cards in this Set
- Front
- Back
Energy |
The capacity to do work |
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Kinetic Energy |
The energy of motion |
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First Law of Thermodynamics |
Energy cannot be created or destroyed |
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Entropy |
Measure of how much the energy of a system is dispersed |
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Second Law of Thermodynamics |
Energy tends to disperse spontaneously |
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Potential energy |
Stored energy |
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Reaction |
Process of chemical change |
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Reactants |
Molecules that enter a reaction |
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Products |
A molecule that remains at the end of a reaction |
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Free energy |
The amount of energy available to do work; depends on the bond entry and entropy |
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Endorgenic |
Type of reaction that requires a net input of free energy to proceed; Converts molecules with low energy to molecules with higher energy. |
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Exergonic |
Type of reaction that ends with a net release of free energy; Convert molecules with high energy to molecules with lower energy. |
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Activation energy |
Minimum amount of energy required to start a reaction |
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ATP Adenosine triphospate |
An energy carrier that couples endorgonic with exergonic reactions in cells; Nucleotide with three phosphate groups whose bonds hold a lot of energy; transfer of phosphate group from ATP to a molecule transfer energy and is used as part of endergonic reaction. |
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Phosphorylation |
The transfer of a phosphate group |
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ATP/ADP cycle |
The cycle of using and replenishing ATP. ATP->ADP. ADP->ATP |
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Catalysis |
The acceleration of a reaction rate by a molecule that is unchanged by participating in the reaction |
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Substrate |
A molecule that is specifically acted upon by an enzyme |
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Active site |
Pocket in an enzyme where substrate bind and a reaction occurs; site is complimentary in shape, size, polarity, and charge to the enzymes substrate |
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Enzyme reaction |
Enzyme enhances the rate of reaction by lowering its activation energy; Enzymes function best at certain temperatures, pH, and salt concentration. 1. Helping substrates get together (Closer the better) 2.Orienting substrates in position that favor reaction 3.inducing a fit between enzyme and substrate 4.shutting out water molecules |
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Induced-fit model |
Substrate binding to an active site improves the fit between the two; Enzyme changes shape for better fit=stronger bond |
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Cofactor |
Atoms or molecules(other than proteins) that associate with an enzyme and is necessary for its function |
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Coenzyme |
Organic molecule that is a cofactor |
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Antioxidant |
Substance that prevents molecules from reacting with oxygen; oxygen reactions often free radicals which attack biological structures of atoms |
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Metabolism |
The activities by which cells acquire and use energy as they build and break down organic molecules. |
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Metabolic pathway |
Series of enzyme-mediated reaction by which cells build, remodel, or break down an organic molecule |
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Feedback inhibition |
Mechanism by which a change that results from some activity decreases or stops the activity |
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Allosteric |
Describes a region of an enzyme other than an active site that can bind regulatory molecules in a way that enhances or inhibits |
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Redox reaction |
Oxidation-reduction reaction in which one molecule accepts electrons (it becomes reduced) from one another molecule (which become oxidized). Also called electron transfer |
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Electron transfer chain |
Array of enzymes and other molecules that accept and give up electrons in sequence, thus releasing the energy of the electrons in usable increments |
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Concentration |
Number of molecules or ions per unit volume; the amount of solute in a given amount of fluid |
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Concentration gradient |
Difference in concentration between adjoining regions of fluid |
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Diffusion |
Net movement of molecules or ions from a region where they are more concentrated to a region where they are less so; Diffusion depends on 5 factors: 1. Size: it takes more energy to move larger molecules which is why smaller molecules diffuse more quickly than larger ones 2. Temperatures: molecules move faster at higher temperature = more collision = faster the diffusion 3. Steepness of the concentration gradient: rate of diffusion is higher with steeper gradient, because molecules collide more often in a region of greater concentration 4. Charge can affect the rate and direction of diffusion; opposite charges attract. 5. Pressure- higher pressure squeezes molecules together = more collisions |
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Hypotonic |
Describes a fluid with lower overall solute concentration relative to another fluid |
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Hypertonic |
Describes a fluid with higher over solute concentration relative to another fluid |
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Isotonic |
Describes two fluids with the same amount of overall solute concentration |
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Osmosis |
The diffusion of water across a selectively permeable membrane I'm response to two differing overall solute concentration ; Fluids flow from hypotonic to hypertonic. |
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Turgor |
Pressure that a fluid exerts against a wall, membrane, or other structure that contains it |
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Osmotic pressure |
Amount of turgor that prevents osmosis into cytoplasm or other hypertonic fluid |
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Passive transport |
Mechanism by which a concentration gradient drives the movement of a solute across a cell membrane through a transport protein. Requires no energy input |
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Active transport |
Energy requiring mechanism by which a transport protein pumps a solute across a cell membrane against its concentrating gradient |
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Exocytosis |
Process by which a cell expels a vesicle ' contents to extracellular fluid |
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Endocytosis |
Process by which a cell takes in a small amount of extracellular fluid by the ballooning inward of its plasma membrane |
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Phagoctosis |
"Cell eating"; an endocytic pathway by which a cell engulfs particles such as microbes or cellular debris |