Term
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Definition
| 1. Selectively accelerate each step in metabolism. Activity is regulated to maintain balance of supply and demand. |
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Term
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Definition
| 1. Release energy by breaking down complex molecules to simpler compounds. (Energy is stored until needed) |
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Term
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Definition
| 1. Consume energy to build complex molecules from simpler compounds. (Energy from catabolic pathways is used in anabolic pathways) |
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Term
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Definition
1. A+X -> B -> C -> D+Y
Initial substrate
Intermediates
End-products |
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Term
1. Energy
2. Kinetic energy
3. Potential energy
3a. Chemical energy |
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Definition
1. The capacity to do work - to move matter against opposing forces.
2. The energy of motion.
3. The energy that matter possesses due to location/structure.
3a. A form of potential energy in molecules from arrangement of atoms. |
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Term
1. Cells do work by ____________.
2. Energy coupling is using an _______ process to drive an _______ process. |
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Definition
1. Energy coupling
2. Exergonic, endergonic |
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Term
Kinds of work (3):
1. Mechanical work
2. Transport work
3. Chemical work
4. Source of energy to power work is _____. |
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Definition
1. Beating of cilia, muscle contraction, chromosomal movement.
2. Pumping substances across membranes.
3. Driving endergonic reactions such as synthesis of polymers from monomers.
4. ATP |
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Term
| 1. ATP (adenosine triphosphate) |
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Definition
| 1. A nucleotide consisting of the nitrogenous base adenine, ribose, and a chain of three phosphate groups. |
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Term
| 1. How are bonds between phosphate groups broken? |
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Definition
1. Hydrolysis
Hydrolysis makes an ATP go to ADP + Pi + energy |
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Term
| 1. The phosphate bonds of ATP are referred to as high-energy bonds, but are actually weak. Why? |
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Definition
| 1. Weak because each phosphate group has a (-) charge; repulsion from each other. |
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Term
1. ATP is regenerated continually by adding a phosphate group back to the ____.
The energy to support renewal comes from catabolic reactions. |
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Definition
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Term
| Regeneration of ATP is an _____1_____ process and requires an investment energy of __2__. |
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Definition
1. Endergonic
2. 7.3 kcal/mol |
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Term
| 1. Mechanical transport and chemical work are almost always powered by what? |
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Definition
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Term
1. Enzymes
2. They __________ activation energy for a reaction.
3. Are enzymes specific for a substrate? |
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Definition
1. Proteins that catalyze reactions in biological systems.
2. Decrease
3. Specific to one substrate, or small group of substrates, yes. |
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Term
1. Are enzymes changed in the reaction?
2. Are enzymes consumed in the reaction? |
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Definition
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Term
Control of enzyme synthesis:
1. Rate of synthesis is limited by what?
2. Rate of synthesis regulated at molecular level by what?
3. Some cells only synthesize certain enzymes after being exposed to the ___________ for that pathway. |
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Definition
1. Protein availability
2. Modulation of gene transcription
3. Initial substrate |
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Term
Control of enzyme activity:
1. Allosteric regulation
1a. Feedback inhibition
1b. Enzyme activation |
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Definition
1. Binding of a protein at a site other than the active site to effect the substrate binding at the active site.
1a. Accumulation of pathway end product inhibits the first enzyme in the pathway.
1b. Requires cofactors. Cofactors act as activators to alter active site and allow enzymes to catalyze reactions. |
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Term
Allosteric regulators:
1. Activators
2. Inhibitors |
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Definition
1. Has a functional active site
2. Lacks an active site |
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Term
| 1. Mechanism of enzyme activity |
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Definition
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Term
1. The reactant an enzyme acts on is the what?
2. What kind of interactions between the substrate and the R groups of A.A. of the protein cause the enzyme to change shape? |
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Definition
1. Substrate
2. Steric interactions. Steric interactions bring the chemical groups of the active site into position for catalysis of the reaction. |
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Term
| 1. Steps to the Lock-And-Key Model of Enzyme Activity |
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Definition
| 1. Substrate binds to enzyme with open active site. Substrate may leave active site unchanged. Substrate may convert to product from enzyme. Product leaves the enzyme. Enzyme is free again. |
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Term
1. Substrate specificity
2. Induced Fit Model |
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Definition
1. Enzyme active site is properly shaped for a specific substrate to bind it.
2. Enzyme changes shape slightly as substrate begins to bind. |
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Term
1. Cofactors
2. Coenzymes |
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Definition
1. Ion or molecule (non-protein) required by an enzyme to be active (Ex: trace metals - hold enzyme normal configuration allowing substrate to bind).
2. Are vitamin derived. Coenzymes do not have direct enzymatic activity, but participate in the enzyme's reaction. Used for multiple reactions (can dissociate and bind with many enzymes). Transfer small chemical groups from one reaction to another. |
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Term
| 1. Coenzymes important in energy metabolism (3) |
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Definition
| 1. NADH from Niacin (H+ group), FAD from Riboflavin (H+ group), Coenzyme A from Pantothenic (acid acetyl group) |
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Term
| Reduction of NAD+ and FAD |
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Definition
FAD +2H --> FADH2
NAD+ + 2H --> NADH + H+ |
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Term
| Factors affecting rates of enzyme-catalyzed reactions (5) |
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Definition
Enzyme's catalytic rate
Enzyme concentration
Substrate concentration
Affinity of enzyme for substrate
Temperature and pH |
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Term
1. Catalytic rate
2. Concentration |
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Definition
1. Amount of product produced per unit time, assuming enzyme is always occupied with substrate
2. Greater enzyme concentration corresponds to greater reaction rate (law of mass action) |
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Term
| 1. Substrate concentration |
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Definition
| 1. Higher [substrate] makes the reaction rate meet the max. Low [substrate] means that not all enzymes are being used at once. |
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Term
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Definition
| 1. Molecules that bind to proteins by weak interaction (+,-) H bonds or ionic bonds. |
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Term
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Definition
| 1. A measure of strength of binding between enzyme and substrate. Higher affinity means that reaction rate is higher even with low [substrate]. Max is reached sooner, as well. |
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Term
| 1. Acidity (pH) and temperature |
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Definition
| 1. Non-specific factors that affect rate of enzyme catalysis. |
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