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44 Cards in this Set
- Front
- Back
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Definition of an Enzyme
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any substance that speeds up a chemical reaction w/o itself being changed, a type of catalyst
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biological catalysts are usually
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protiens
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what does an enzyme do?
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lowers activation energy
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energy given off
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exothermic / exergonic
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absorbs energy
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endothermic / endergonic
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most enzymes end in
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ase (sucrase and sucrose)
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substrate + enzyme =
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enzyme substrate comples
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Can enzymes be changed chemically?
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yes, but must be returned to original form
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what determines enzyme specificity?
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tertiary structure of enzyme
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what is it called when enzymes change shape after bonding with the substrate?
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induced fit
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what 4 things attract an enzyme to the substrate?
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- hydrogen bonds
-attraction + repulsion of charged functional groups - introduction of hydrophobic groups - covalent bonds |
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what is it called when an enzyme is made unusable?
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denatured
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what 2 things assist enzymes in a reaction?
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- prosthetic group
- hydrolyze reactions |
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say things about prosthetic groups - what are they? that can they be? (3)
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they are a tightly bonded non-protien
can be: -single metal ion - metal ion within a small organic molecule - COENZYME (may donate or accept e- or hydrogen bonds) also may make substrate more reactive, or transfer PO4 groups. NOT protien in nature. |
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what is a hydrolyze reaction?
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break substrate chain by adding H2O to molecules
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what two things can regulate enzymes?
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substrate concentration
inhibitors |
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what two types of inhibitors are there?
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irreversible and reversible
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What are irreversible inhibitors?
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attach to enzyme and doesnt let go, generally to active side, changes tertiary structure
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what two types of reversible inhibitors are there?
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competitive and noncompetitive
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what are reversible inhibitors?
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once they remove themselves the enzyme works again
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what are competitive inhibitors?
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block active site, can be products, chemicals, etc.
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what are noncompetitive inhibitors?
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bound at another place on enzyme, changes shape, slowing activity of enzyme or stopping it altogether
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when do allosteric enzymes occur?
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in enzymes make of 2+ polypeptide units (i.e. have a quaternary structure)
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what is the activity of an enzyme determined by? what are they?
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the effectors which bind to the allosteric site, either speeding up or slowing down the enzyme.
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synonym for allosteric site
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regulatory subunit
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What is ATP
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the energy storage in molecules
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what is ATP made of
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adenosine (adenine + ribose) and 3 phosphate groups (each is charged)
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What is the difference between ADP, ATP, and AMP?
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di, tri, mono (# of phosphate groups)
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How is ATP broken apart?
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many different enzymes break it appart, releasing 12Kcal/mol of ATP
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How many molecules of ATP are needed per second for cell activities?
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millions
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Where does this free energ come from when ATP is broken down?
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large - charge in the phosphate groups, released when bond is broken, in high energy bonds
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What is respiration?
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the breaking down of glucose to yield ATP, 1st stage doesn't require oxygen, 2nd does
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why is ATP necissary?
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energy in glucose molecules are not readily available to cells, so the energy is transferred to the molecule ATP
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What is a wavy line in a chemical reaction?
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a high energy bond
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Most cellular activities, reaction goes _________
in respiration it goes ___________ |
ATP -> ADP
ADP -> ATP |
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What is NAD?
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the "gold mine of energy", nicotinamide adenine dinucleotide
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what two forms does NAD come in?
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NADH (or NADH + H+)
NAD+ |
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what is NAD's function?
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to carry e-, H+, free energy
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what two reactions occur with NAD?
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oxidation and reduction
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What is oxidation?
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loss of electrons
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what is reduction?
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gain of electrons
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Reduction equations
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NAD+ + e- + H+ --> NADH
NAD+ + 2e- + 2H+ --> NADH + H+ |
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Oxidation equations
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NADH --> NAD+ + e- + H+
NADH + H+ --> NAD+ + 2e- + 2H+ |
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energy released from the oxidation reaction of NAD?
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52.4 Kcal/mol of NADH
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