ENZYMES Flashcards
Enzymes catalyze all the chemical reactions required to ________, ________, and _______ life
Build, sustain, reproduce
An enzyme is a _______
Catalyst
An enzyme is a catalyst that-
-Accelerates the rate of one or more chemical reactions
-Is not permanently changed or consumed by the reaction it catalyzes
-Is a protein or RNA molecule (ribozyme)
How many chemical reactions occur in a eukaryotic cell?
~1 million
Enzymes enable each chemical reaction to occur at the proper…
Location, time, and generate correct product concentration
Enzymes significantly ______ the rates of chemical reactions enabling life to occur
Accelerate
The average enzyme performs how many reactions per second?
~1,000
Enzymes lower the ______ _______ required for a chemical reaction to occur
Activation energy
Most enzymes are…
Proteins
RNA molecules called ribozymes
What is the active site?
Part of the enzyme that catalyzes a specific chemical reaction
What “fits” in the active site?
The substrate
Activation energy is the amount of energy….
A substrate must absorb to initiate a chemical reaction
Activation energy is required for a substrate to enter the _________ ________
Transition state
What is the transition state?
An intermediate, energized, unstable phase ready to react to form product
Cells use a sequence of enzymes called a _________ pathway to synthesize many types of product molecules
Biochemical
What is a biochemical pathway and its purpose?
Sequence of enzymes; synthesizes many types of product molecules
When the cell has the necessary concentration of the product, the product will _______ an enzyme in the pathway
Inhibit
The _______ of enzyme #1 becomes the ________ for enzyme #2
Product; substrate
What enables cells to maintain the proper concentration of each product?
Rapid and reversible enzyme regulation
What is negative feedback regulation?
Controls the activity of many enzymes to maintain proper product levels
When does negative feedback occur?
When the restoration of normal conditions stops the corrective process
Two types of negative feedback regulation
-Competitive inhibition
-Noncompetitive inhibition
Competitive inhibition
Competitive inhibitor interferes with active site of enzyme so substrate cannot bind
The inhibitor is in similar shape to the substrate
Inhibitor binds to active site, prevents the substrate from binding
Noncompetitive inhibition
Allosteric inhibitor changes shape of enzyme so it cannot bind to substrate
Causes the enzyme to change shape
Closes the active site, substrate cannot bind to active site
