BIO 2 Exam 2: Enzymes (1)

Question 1

Defining Enzymes

Answer 1

Proteins that catalyze a specific chemical reaction

Lower EA

No effect on Delta G (Degree) or Keq

Question 2

Enzyme (4) Facts

Answer 2

Enzymes act upon one substrate (reactant)

Substrate binds to the enzyme’s active site

Products are released

Enzyme is unchanged – can act many times

Question 3

How do Enzymes Work?

Answer 3

Lock-and-Key Model

Lock-and-Key Model Induced Fit Model (Stabilizes the transition state)

Enzymes are bidirectional catalysts

No change on equilibrium state

Get there quicker

Question 4

Enzymology

Answer 4

Enzymes lower EA but don’t affect Delta G Degree

Speed up reactions but no effect on Keq

Substrate <-> Product

Question 5

Measuring Enzyme Activity Definition

Answer 5

Measuring reaction rate

Mix enzyme and substrate together

Measure Product concentration over time

Question 6

Measuring Enzyme Activity when the curve flattens out (plateaus)?

Answer 6

Equilibrium!

Forward and reverse reaction rates are equal

Question 7

Explaining Measuring Enzyme Activity

Answer 7

Slope of the curve at early times is the reaction rate

[Product]/time

initial velocity (vi or vo)

Enzyme activity

Question 8

Michaelis-Menten Kinetics

Answer 8

vi relies on binding + catalysis

Km reflects substrate binding

Lower Km means tighter substrate binding (Km gives info about substrate binding. Vmax gives info about catalysis. Together, they determine the reaction rate)