Topic 8

Question 1

Gibbs Free Energy

Answer 1

• energy available to do work in a chemical system

Question 2

G Depends On

Answer 2

• 1. chemical nature of molecule
• 2. environmental conditions
     
     • T, P, concentration

Question 3

Chemical Standard

Answer 3

• T: 298K
• P: 1 bar
• C: all molecules at 1 mol/L

Question 4

Adenosine Triphosphate (ATP)

Answer 4

• main energy carrier in living systems
• high energy bond
  - because the reaction is spontaneous

Question 5

High- Energy Intermediate

Answer 5

• since it is phosphorylated
• not a transition state, it is a distinct intermediate

Question 6

Metabolism

Answer 6

• sum of all chemical processes in all cells

Question 7

Anabolism

Answer 7

• make larger molecules out of smaller
• need free energy

Question 8

Ways to Regulate an Irreversible Reaction

Answer 8

1. Change amount of enzyme
   
   • small processes, has lots of steps, takes time
2. Change location of enzyme
3. Allosteric Regulation (rapid)
4. Covalent Modification (rapid)

Question 9

Allosteric definition

Answer 9

• “other solid” or “Other shape”

Question 9

Allosteric Enzymes

Answer 9

• changes the shape/active site ofthe enzyme
• binding of effector to allosteric site
• changes active site
• Usually multimeric
• higher [effector] = move binding
  - shifts equilibrium to the right

Question 10

Covalent Modifications

Answer 10

• covalent addition of a chemical group (eg. phosphate) to the protein
• chemical group changes enyme conformation and activity
  - some enzymes are inactive in phosphate form, to make them active we have to dephosphorylate them

Question 10

2 Subunits

Answer 10

1. catalytic
2. regulatory