Download Enzyme LG 09

Name___________________________________________ Hr ____
1. What kind of macromolecule is an enzyme? What is it composed up of?
2. Use activity 5D to help answer the following questions:
a. What is the role of energy of activation (EA) in exergonic reactions?
b. What role does an enzyme play in EA?
c. Why don’t enzymes catalyze many different reactions?
3. In the space to the right – Draw a
Free energy graph that shows what
enzymes do to EA. Label: reactants,
products, EA with and without enzymes
4. Contrast the induced fit model with the lock and key model.
5. What conditions could slow down your enzyme? List at least 4.
6. What conditions could speed up your enzyme? List at least 4.
7. Label the pictures to the right.
a. define both competitive & noncompetitive inhibition
8. Compare and contrast coenzyme and cofactor
9. Define Allosteric enzymes and explain how they are regulated
10. What is the benefit of feedback inhibition?
11. How do most enzyme names end?
Review:
12. Write if the characteristic is endergonic (en) or exergonic (ex)
_____ Energy rich products
_____ Catabolic
_____ “down hill” reaction
_____ “up hill’ reaction
_____ Anabolic
_____ Used to break down
_____ Energy rich reactants
_____ Releases energy
_____ requires energy
_____ Used to build
13. Write if the following is a Carbohydrate (c), Lipids (l), Protein (p), or nucleic acid (n)
_____ Glycerol backbone
_____ Glycogen
_____ Phospholipid
_____ Insulation
_____ Made of amino acids
_____ Energy Storage _____ Structural
_____ Enzymes
_____ Carries genetic info
_____ Energy
_____ Alpha helix & pleated sheet
Circle & Write the letter that best answers each problem in the box at the bottom of the page
14. The active site of an enzyme is
19. Inhibition of an enzyme is irreversible when
a. the region of a product that detaches from the
a. bonds form between inhibitor and enzyme.
enzyme.
b. a noncompetitive inhibitor is involved.
b. the region of a substrate that is changed by an
c. the shape of the enzyme is changed.
enzyme.
d. a competitive inhibitor is involved.
c. the highly changeable portion of an enzyme that
e. None of the choices are correct.
adapts to fit the substrates of various reactions.
20. How does inhibition of an enzyme-catalyzed
d. the region of an enzyme that attaches to a substrate.
reaction by a competitive inhibitor differ from
e. None of the choices are correct.
inhibition by a noncompetitive inhibitor?
15. Which one of the following is false?
a. Competitive inhibitors interfere with the
a. Enzymes emerge unchanged from the reactions
enzyme; noncompetitive inhibitors interfere
they catalyze.
with the reactants.
b. An enzyme binds to its substrate at the enzyme's
b. Competitive inhibitors bind to the enzyme
active site.
reversibly; noncompetitive inhibitors bind to
it irreversibly.
c. Enzymes are very specific for certain substrates.
c. Competitive inhibitors change the enzyme's
d. An enzyme's function depends on its 3D shape.
tertiary structure; noncompetitive inhibitors
e. Enzymes are used up in chemical reactions.
cause polypeptide subunits to dissociate.
16. Which one of the following is true?
d. Competitive inhibitors bind to the active site
a. Enzymes are inorganic.
of the enzyme; noncompetitive inhibitors
b. An enzyme's function is unaffected by changes in
bind to a different site.
pH.
e. Competitive inhibitors are inorganic
c. Enzymes catalyze specific reactions.
substances such as metal ions;
d. Enzymes are the reactants in a chemical reaction.
noncompetitive inhibitors are vitamins or
e. All enzymes depend on protein cofactors to
vitamin derivatives.
function.
21. Bacterial production of the enzymes needed for the
17. Heating inactivates enzymes by
synthesis of the amino acid tryptophan declines with
a. breaking the covalent bonds that hold the molecule
increasing levels of tryptophan and increases as
together.
tryptophan levels decline. This is an example of
b. removing phosphate groups from the enzyme.
a. irreversible inhibition.
c. changing the enzyme's three-dimensional shape.
b. noncompetitive inhibition.
d. causing enzyme molecules to stick together.
c. competitive inhibition.
e. None of the choices are correct.
d. positive feedback.
18. Which of the following can affect the rate of an enzymee. feedback inhibition.
catalyzed reaction?
22. When an enzyme catalyzes a reaction,
a. competitive inhibitors
a. it becomes a product.
b. temperature
b. it lowers the activation energy of the
c. noncompetitive inhibitors
reaction.
d. pH
c. it raises the activation energy of the reaction.
e. All choices are correct
d. it acts as a reactant.
e. None of the choices are correct.
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