Biological Molecules: Enzymes: In Depth (Ms.D)

Question 1

How do ENZYMES SPEED UP chemical reactions? (ID)

Answer 1

-They act as CATALYSTS
-Lower the ACTIVATION ENERGY
-Allow REACTIONS to take place at a LOWER TEMP.
-HOLD SUBSTRATES close together, reduces REPULSION, BONDS BREAK easier
-Put more STRAIN ON BONDS so they BREAK easier

Question 2

What are some FEATURES of ENZYMES?

Answer 2

-PROTEINS with a 3D STRUCTURE (TERTIARY)
-COMPLEMENTARY SHAPE
-Only BINDS onto certain SUBSTRATES, forming ES-COMPLEXES

Question 3

Describe the LOCK AND KEY MODEL

Answer 3

-Shape of ACTIVE SITE is COMPLEMENTARY to SUBSTRATE
-SUBSTRATE fits PERFECTLY when they collide, forming an ES-COMPLEX

Question 4

Describe the INDUCED FIT MODEL

Answer 4

-AS is NOT COMPLEMENTARY
-On collision, AS changes SHAPE SLIGHTLY to form ES-COMPLEX
-Interacts with the R-GROUP that form the AS
-Interaction causes a small SHAPE CHANGE in AS, making it COMPLEMENTARY to SUBSTRATE
-After reaction finishes, SHAPE REVERTS

Question 5

Describe the RELATION between the ENZYME CONC. and ROR on a GRAPH

Answer 5

-As ENZYME CONC. INCREASES, the NO. AS INCREASES available for SUBTRATES to collide
-More ES-COMPLEXES can form an ENZYME CONC. INCREASES
-ROR will INCREASE until SUBSTRATE becomes LIMITING FACTOR
–>More ENZYMES than SUBSTRATES, so INCREASE of CONC. will have no effect on rate

Question 6

Describe the RELATION between the SUBSTRATE CONC. and ROR on a GRAPH

Answer 6

-As SUBSTRATE CONC. INCREASES, ROR INCREASES as there are more SUBSTRATE MOLECULES
-More collisions, so MORE ES-COMPLEXES FORM
-ROR DECREASES as ENZYME CONC. becomes LIMITING FACTOR
–>All ENZYME AS are OCCUPIED (SATURATION POINT)
-Increase in SUBSTRATE CONC. has no effect on ROR