20 Cards in this Set
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first law of thermodynamics
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the principle of conservation of energy: energy can be transferred and transformed, but it cannot be created or destroyed.
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second law of thermodynamics
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the principle stating that every energy transfer or transformation increases the entropy of the universe. usable forms of energy are at least partly converted to heat.
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Exergonic Reactions
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Releases energy (– ΔG). Is spontaneous.
Chemical reaction where there is more energy on the reactants side than the product side.
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Endergonic Reactions
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positive free energy change (+ ΔG)
requires addition of free energy
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ATP Hydrolysis (water break down)
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-a cycle
-releases energy and is exergonic
delta G: -7.3 kcal/mole
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energy coupling
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The use of an exergonic process to drive an endergonic one
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Catalyst
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-something that causes or speeds up a process without changing itself.
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How to overcome activation energy
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-Large amounts of heat
-Using enzymes to lower activation energy such as a catalyst.
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Enzymes
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Helps speed up chemical reactions.
Different enzymes perform different functions
Enzyme - substrate complex - induced fit
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4 Ways Active Sites lower the Activation Energy
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Orienting substrates correctly
Straining substrate bonds
Providing a favorable micro environment(ph, temp)
Covalently bonding to the substrate(direct)
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Reaction Rate vs. Substrate Concentration
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Reaction rate increases as substrate is added until it reaches its Vmax. line. leveling off occurs because active sites become occupied and substrates have to wait for active sites to open.
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Saturation Kinetics
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at low substrate concentrations, increasing the concentration will increase the reaction rate but at high substrate concentrations, increasing the substrate has little or no effect on the reaction rate because it has reached Vmax.
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Non-competitive Inhibitors
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Effectively neutralize the enzyme making it inactive. Thus, Vmax is lowered.
Km stays the same because the enzyme concentration is lowered.
Substrate has same affinity. Adding more will not force out the inhibitors.
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How does temperature and pH effect an enzymes function?
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Enzymes can only function in a vary narrow range of temperature and pH. If an enzyme gets too hot or too far out of its narrow pH range it will start to denature (break down) and not function.
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Benefits of Metabolism in cells
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Versatility- many uses, moves easily/changeable.
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anabolic pathway
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consumes energy to build up complex molecules from simpler molecules.
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catabolic pathways?
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Pathways of enzymes that breakdown food molecules
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. Between allostery and gene regulation, which is more related to long-term control of metabolism and whichto short-term control? Why?
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short term = reversible phosphorylation
long term = gene expression, because DNA is permanent and activity is not.
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What is the difference in half-reactions between reduction and oxidation? *Emphasize on hydrogen*
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- reduction is gaining
- Oxidation is losing
Hydrogen is being oxidized and oxygen is being reduced.
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Role of NAD and FAD in cellular respiration
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Transfer electrons to an electron transport chain
Electron accepters
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BIO 201: TEST 2