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41 Cards in this Set
- Front
- Back
Definition of Metabolism |
All the chemical changes that occur in an organism |
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Enzyme |
serve as catalysts (chemical agents that change the rate of reaction without being consumed) |
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Catabolic metabolism |
Breaks down complex molecules to simpler compounds. Breaking bonds releases energy |
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Anabolic metabolism |
Consumes energy to build complex molecules from simpler ones. Forming bonds requires energy. |
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Energy coupling |
interaction between catabolic and anabolic pathways
catabolic pathways often energize anabolic ones |
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Energy |
The ability to rearrange a collection of matter, the capacity to do work |
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Kinetic Energy |
when energy is associated with the relative motion of objects |
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Potential Energy |
the energy present due to an object's position or composition |
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Chemical Energy |
potential energy available for release in a chemical reaction |
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Thermodynamics |
The study of energy transformations that occur in a collection of matter |
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1st Law of Thermodynamics |
Energy can be transferred and transformed but it cannot be created or destroyed. Conservation of energy |
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2nd Law of Thermodynamics |
Every energy transformation or transfer increases the entropy of the universe. |
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Entropy |
Measure of disorder, takes the form of heat |
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Free Energy (G) |
Portion of a system's energy that is available to perform work. All molecules have free energy |
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Equation for change in free energy (∆G) |
∆G= ∆H - T∆S
H= total energy T= absolute temperature in Kelvin S= system's entropy |
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Spontaneous Reaction |
Occurs without energy, ∆G < 0 |
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Non-spontaneous Reaction |
Requires energy to proceed, ∆G > 0 |
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Exergonic reaction |
∆G < 0, reactions proceed with a net release of free energy |
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Endergonic reaction |
∆G > 0, reactions absorb free energy from the environment |
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Cellular respiration |
C6H12O6 (sugar) + 6O2 yields 6CO2 and 6H2O
Exergonic
∆G= -686 kcal/mol per 180 grams of glucose |
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ATP |
Adenosine triphosphate, source of energy that drives cellular work |
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Structure of ATP |
1. Adenine nitrogenous base 2. Ribose sugar 3. 3 phosphate groups |
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Where is the energy stored in ATP? |
between the bonds of the three phosphates |
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How does ATP perform work? |
Water hydrolyzes terminal phosphate bond and a molecule of inorganic phosphate is removed (exergonic)
∆G= -7.3 kcal/mol |
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What happens to the phosphate removed from ATP? |
Phosphate group is transferred to some other molecule with the help of an enzyme (phosphorylated) |
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Energy coupling |
Cell uses energy released by ATP hydrolysis to drive endergonic reactions |
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How is ATP regenerated? |
Addition of a phosphate to ADP |
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What enzyme hydrolyzes sucrose into glucose and fructose? |
Sucrase |
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How do catalysts increase the rate of reactions? |
They lower the activation energy |
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Substrates |
Substances on which the enzyme will work. Enzymes pick specific ones |
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Active site |
Place on enzyme on which substrate binds, pocket or groove on surface of protein |
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3 Factors Affecting Enzyme Activity |
1. Environmental conditions
2. Cofactors
3. Inhibitors |
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Environmental factors affecting enzyme activity |
1. Temperature
2. pH Level
3. Salt concentration |
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Cofactors |
Non-protein helpers for catalytic activity |
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Inorganic cofactors |
metal atoms (zinc, iron, copper) |
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Organic molecules |
Coenzymes (vitamins) |
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Competitive Inhibitor |
Competes with substrate for active site, interfering with enzyme activity |
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How to overcome competitive inhibitor |
Increase amount of substrate so there is more substrate than competitive inhibitor |
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Non-competitive Inhibitor |
Does not directly compete for active site, but changes shape of active site when it attaches to allosteric site |
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Activators |
Makes products faster, process runs more smoothly |
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Feedback Inhibition |
Near the end of a process, final product will recognize that there is an abundance of such product. Binds to first enzyme at allosteric site and halts process |