Enzymes 2 and Carbohydrates

Question 1

Lineweaver-Burk plot x-intercept

Answer 1

-1/km

Question 2

Lineweaver-Burk plot y-intercept

Answer 2

1/vmax

Question 3

Lineweaver-Burk plot slope

Answer 3

km/vmax

Question 4

Lineweaver-Burk plot x-axis

Answer 4

1/[s]

Question 5

Lineweaver-Burk plot y-axis

Answer 5

1/vo

Question 6

competitive inhibition: binding site

Answer 6

• I binds to E only
• I and S bind at same site, compete for binding
  
  • active site, doesn’t affect catalysis

Question 7

competitive inhibition: km

Answer 7

increases

Question 8

competitive inhibition: vmax

Answer 8

no change

Question 9

uncompetitive inhibition: binding site

Answer 9

• I binds to ES only
• I and S bind to distinct sites
  
  • I does not affect substrate binding
  • inhibits catalytic function

Question 10

uncompetitive inhibition: Km

Answer 10

decreases

Question 11

uncompetitive inhibition: vmax

Answer 11

decreases

Question 12

mixed inhibition: binding

Answer 12

• I binds E and ES
• I and S bind at distinct sites
• I binds enzyme with or without substrate
  
  • affects catalysis and binding

Question 13

mixed inhibition: vmax

Answer 13

decreases

Question 14

mixed inhibition: Km

Answer 14

can increase or decrease
- extreme case becomes noncompetitive and Km is unchanged

Question 15

irreversible inhibition

Answer 15

• covalent bond between E and I
• transition state analogs (tight binding inhibitors)
  
  • shut down enzyme by resembling transition state

Question 16

regulatory noncovalent enzymes

Answer 16

allosteric enzyme
- have at least one substrate where Vo vs [s] is sigmoidal
- substrate as activator: homotropic modulator
- multisubunit proteins

Question 17

regulatory covalent enzymes

Answer 17

reversible, requiring one enzyme for activation and another for inactivation
common mechanism: phosphorylation of ser, thr, tyr, his

Question 18

carbohydrate structure

Answer 18

• Cn(H2O)n
• produced from CO2 and H2O via photosynthesis in plants
• large size range

Question 19

carbohydrate function

Answer 19

• energy source, storage
• structural components

Question 20

d-glyceraldehyde

Answer 20

aldotriose/aldose
3 carbons

Question 21

dihydroxyacetone

Answer 21

ketomose
3 carbons

Question 22

d-ribose

Answer 22

5 carbons
all -OH on right side

Question 23

d-glucose

Answer 23

6 carbons
aldohexose
right: OH, H, OH, OH

Question 24

d-mannose

Answer 24

C2 epimer of glucose
right: H, H, OH, OH

Question 25

d-galactose

Answer 25

C4 epimer of glucose
right: OH, H, H, OH

Question 26

d-fructose

Answer 26

ketomose

Question 27

chitin

Answer 27

structural component of arthropods
- Beta 1,4 linked polymer of N-acetylglucosamide

Question 28

starch

Answer 28

amylose, amylopectin
- amylose: unbranched a1-4 polymer of glucose
- amylopectin: 1,4 polymer with 1,6 branches

Question 29

glycogen

Answer 29

storage unit in animals
a1-4 linked polymer with a1-6 branches
reducing and non-reducing ends: rapid mobilization

Question 30

cellulose

Answer 30

b1-4 linked polymer of glucose, no branching
one reducing end, one non-reducing end
extensive H-bonding