Enzymes

Question 1

Lock and Key model

Answer 1

Question 2

Induced fit model

Answer 2

Question 3

Factors affecting enzyme function

Answer 3

• pH, salinity, temperature, cofactor association
  
  • Apoenzyme: enzyme without its cofactor
  • Holoenzyme: enzyme with its cofactor

Question 4

Enzyme Regulation

Answer 4

• covalent modification i.e. phosphorylation
• proteolytic cleavage (zymogens)
• Association with other proetins
• Allosteric regulation (feedback inhibition)

Question 5

Proteolytic cleavage

Answer 5

i.e. zymogens

Question 6

Saturation

Answer 6

All active sites are occupied by substrate, so increasing [s] will not increase the rate (Vmax)

Question 7

Km (michaelis constant)

Answer 7

• Substrate concentration at 1/2 Vmax
• The smaller the K_m, the greater affinity for the substrate

Question 8

Michaelis-Menten equation

Answer 8

Question 9

Lineweaver-Burk Plots

Answer 9

Question 10

Competitive, uncompetitve, noncompetitive

inhibition

Answer 10

Question 11

Oxidoreductases

Answer 11

catalyze redox reactions (electron transfer)

Question 12

Transferases

Answer 12

catalyze transfer of functional groups

Question 13

Hydrolases

Answer 13

catalyze cleavage of molecules driven by the addition of water

Question 14

Lyases

Answer 14

catalyze addition of atoms or groups to a double bond

Question 15

Isomerases

Answer 15

catalyze transfer of functional groups within a

molecule (creates different isomers of the same molecule)

i.e. mutase

Question 16

Ligases

Answer 16

catalyze linking two molecules into a larger one