1Catalysts
molecules that speed up reactions by lowering activation energy.
2Catalysts are ___ consumed during reactions.
NOT
3The enzyme is ___ at the end of the reaction.
unchanged
4Enzymes are made of ___.
proteins
5Anything that affects ____ affects the function of the enzyme.
proteins
6Enzyme
Biological catalyst that speeds up reactions that are most often proteins.
7Enzyme can be very ___ to a substrate.
specific
8Substrate
A substance on which an enzyme acts.
9A substrate binds to the ___ on the enzyme.
active site
10Active site
A region on an enzyme that binds to a protein or other substance during a reaction.
11Induced fit
A model of enzyme action where the enzyme's active site changes shape to bind more effectively with its substrate.
12Enzyme substrate complex
A temporary structure formed when a substrate molecule binds to an enzyme's active site.
13Two types of enzyme helpers
Cofactors and coenzymes
14Coenzyme
A nonprotein compound that is necessary for the functioning of an enzyme.
15Cofactor
A substance (other than the substrate) whose presence is essential for the activity of an enzyme.
16Difference between cofactor and coenzyme
A coenzyme is a specific type of cofactor that is always an organic molecule.
17Cofactors: ___ (necessary for some enzymes to function)
Metallic ions
18Coenzyme: ___ (vitamins)
Organic molecules
19Cofactors bind to the ___ to activate it or binds ___ (opposite site of the active site).
Active site, allosterically
20Types of enzyme activity
Normal binding, competitive inhibition, and noncompetitive inhibition.
21Allosteric site
A binding site on a protein, such as an enzyme or receptor, that is separate from the active site.
22Normal binding
A substrate can bind normally to the active site of an enzyme.
23Competitive inhibition
A competitive inhibitor mimics the substrate, competing for the active site.
24Noncompetitive inhibition
A noncompetitive inhibitor binds to the enzyme away from the active site, altering the shape of the enzyme so the active site functions less effectively if at all.
25Competitive inhibition
Compete for active site.
26Competitive inhibition ___ overridden by adding more substrate.
Can be
27Noncompetitive inhibition
Inhibit without binding to active site (allosteric).
28Noncompetitive inhibition ___ overridden by adding more substrate.
Cannot be
29In noncompetitive inhibition, the inhibitor binding elsewhere leads to shape change (= ___) in the enzyme.
Conformational change
30The substrate ___ fit the active site anymore.
does not
31Conformational change
Shape change
32Environmental conditions that affect enzymes
Temperature, pH, and salt concentration
33Temperature
Determines amount of kinetic energy
34Lower temperature
Less kinetic energy means products form slowly.
35Increasing temperature
Increases kinetic energy and increases activity.
36If temperature is too high
The structure of enzyme denatures and substrate no longer fits properly. Activity decreases.
37pH
Measure of hydrogen ions in solution.
39High pH (pH of 10)
Basic
40Effect of deviations from optimum pH
Charges interfere with 3D structure of enzymes meaning a decline in activity.
41Effect of salt concentration (NaCl)
Inorganic ions interfere with ionic bonds in enzymes.
42Enzyme concentration
More enzymes = faster reaction (as long as substrate is not limiting).
43Substrate concentration
More substrate = increased activity rate (until saturation point).
44Saturation point
Maximum activity where all enzymes are bound with substrate (plateau).
45Gibbs Free Energy
Energy available in a system for a chemical reaction.
46Negative Gibbs Free Energy
Reaction is spontaneous.
47Positive Gibbs Free Energy
Reaction is non-spontaneous (requires energy input).
48Gibbs Free Energy is zero
Forward and reverse reaction rates are equal.
49Entropy (S)
A measure of the system's disorder or randomness.
50Buffer
A solution that resists changes in pH when small amounts of acid or base are added.
51Gibbs Free Energy ___ affected by catalysts or enzymes.
IS NOT
52Outside of optimum environmental conditions
Rates of reactions can slow or enzymes can denature (become non-functional).
53Null hypothesis
There will be no effect.
54Alternative hypothesis
There will be an effect.
55Independent variable (variable that is changed)
x-axis
56Dependent variable (variable that is measured)
y-axis