1. Which of the following best describes enzymes?
(A) Enzymes are biological catalysts that speed up a chemical reaction by providing and alternative pathway with lower activation energy.
(B) Enzymes are only proteins and usually it speeds up the rate of a reaction when required by the body.
(C) Enzymes are large biological molecules responsible for the thousands of chemical reactions for life sustenance.
(D) Enzymes influence chemical reactions in living systems by affecting the rate at which reactions occur
(E) Enzymes are protein catalysts that speed up a chemical reaction by lowering activation energy.
2. At high temperatures, the rate of enzyme action decreases because the increased heat
(A) changes the pH of the system
(B) alters the active site of the enzyme
(C) the reaction is in dynamic equilibrium
(D) the ratio of enzyme concentration to substrate concentration is 1:2
(E) increases the concentration of the enzyme
3. Which is true for the lock and key hypothesis?
1. substrate changes active site of the enzyme structure
2. enzyme’s active site has a complementary shape of to the substrate
3. the functioning and role played by one enzyme is controlled by a single gene
4. R groups of the amino acids in the active site forms temporary bonds
(A) 1 only
(B) 1, 4
(C) 2, 3
(D) 2, 4
(E) All of the above
4. What defines a co-factor?
(A) organic co factors
(B) non-protein substances required by most enzymes for their efficient activity
(C) assist in the formation of the enzyme-substrate complex
(D) an unstable structure intermediate between the reactants and the products
(E) hold substrate in a correct orientation for it to react with the active site
5. Competitive inhibition….
(A) Binds at different sites on the enzyme not the active site
(B) Only binds to the enzyme-substrate complex away from the active site
(C) Binds to the active site only
(D) Binds at a separate site from the active site
(E) Km maybe increased or decreased