Chapter 8 Part 2 Enzymes

Question 1

metabolic pathway?
how do enzymes help?

Answer 1

interconnected pathways that organize chem reactions in cells
-enzymes help organize and regulate. easier to capture free energy in small changes. 3-D shape contributes to framework.

Question 2

catalyst

Answer 2

increase rates of chem reactions. remain the same and are not altered.

Question 3

activation energy

Answer 3

amount of energy needed to start a chem reaction
-acts as energy barrier and causes reactions to be slow

Question 4

transition state

Answer 4

caused by activation energy putting reactants in a reactive mode

Question 5

transition state intermediate

Answer 5

activation energy changes the reactions into unstable forms with higher free energy

Question 6

what are reactants in an enzyme-catalyzed reactin?

Answer 6

substrate

Question 7

what is the three dimensional location of an enzyme where the substrate binds to?

Answer 7

active site

Question 8

what are reactants in an enzyme-catalyzed reaction?

Answer 8

substrate

Question 9

enzyme substrate complex

Answer 9

when a substrate binds to the active site of an enzyme. the shape of the enzyme can change but returns to original shape.
-help by hydrogen bonds, electrical attraction, or covalent bonds.

Question 10

characteristics of enzymes

Answer 10

-highly specific- bind to 1 or 2 closely related reactants
-reactants are called substrates
-substrate binds to active site
-3-D shape determined by R-groups makes specificity.

Question 11

Enzymes ____ activation energy/ energy barrier for reactions.

Answer 11

lower

Question 12

Do enzymes change the final equilibrium and change of free energy?

Answer 12

No, it reaches result faster

Question 13

enzymes lower activation energy by:

Answer 13

-substrate orientation
-inducing strain
-adding temporary chem groups

Question 14

irreversible inhibition ____ binds to side chains in the active side and ____ _ inactivates the enzyme

Answer 14

covalently
permanently

Question 15

reversible inhibitor binds _____ to active site and prevents substrate from binding. Not permanent

Answer 15

noncovalently

Question 16

What are the three types of reversible inhibitors?

Answer 16

-competitive inhibitor
-uncompetitive inhibitor
-noncompetitive inhibitor

Question 17

competitive inhibitor

Answer 17

compete with natural substrate for binding.
-depends on concentration of inhibitors and natural substrate

Question 18

uncompetitive inhibitors prevent the release of products by

Answer 18

binding to the enzyme substrate complex

Question 19

noncompetitive inhibitors

Answer 19

bind to enzyme at a different site causing a change in shape
-prevents binding or productivity rate of product.

Question 20

feedback inhibitors

Answer 20

final product acts as noncompetitive inhibitor of the first enzyme which shuts down its own production.

Question 21

rate changes with enzyme concentrations

Answer 21

activity rate is faster

Question 22

substrate concentration effects rate by

Answer 22

increases rate.
-when all enzymes reach max rate, enzyme is saturated.

Question 23

effect of pH

Answer 23

enzymes are highly reactive at specific pH.
-activity decreases as solution is made more acidic or basic

Question 24

basic

Answer 24

low H = high pH

Question 25

acidic

Answer 25

high H = low pH

Question 26

temperature affects rate

Answer 26

every enzyme has optimal temp for activity.
-when temp is too high noncovalent bonds break and enzyme is denatured.