ATP and hydrolysis of ATP

Question 1

What is ATP the link between?

Answer 1

Catabolism and anabolism

Question 2

Why do we use ATP?

Answer 2

because it’s metabolically available, kinetically stable, and chemically versatile
it makes delta G negative and favourable (exergonic)

Question 3

What does the hydrolysis of ATP do?

Answer 3

Drives reactions forward

Question 4

What does the hydrolysis of ATP result in?

Answer 4

Results in Hydrolysis of both phosphoanhydride bonds of ATP

Question 5

Where does the energy released takes place in?

Answer 5

Phosphates - the 2 high energy phosphoanhydride linkages

Question 6

First reaction of hydrolysis of ATP - nucleophilic attack of Y

Answer 6

Yields ADP and Pi only releasing 30kJ
ATP->ADP+Pi

Question 7

Second reaction of hydrolysis of ATP - nucleophilic attack of a

Answer 7

yields AMP and phosphate (PPi)
ATP->AMP+PPi

Question 8

The energy required for the activation of fatty acids to fatty acyl-CoA is provided by the hydrolysis of ATP to AMP + PPi. Explain why this mode of ATP hydrolysis leads to the release of twice the amount of energy as the hydrolysis of ATP to ADP + Pi?

Answer 8

The hydrolysis between a and B linkages yields AMP and PPi. The PPi gets immediately hydrolyzed to 2Pi resulting in the hydrolysis of both phosphoanhydride bonds.

Question 9

What factors into the large and negative delta G?

Answer 9

1. hydrolysis releases electrostatic repulsion among negative charges
2. The product Pi has greater resonance stabilization than ATP does
3. ADP2- product rapidly ionizes to release a protein into a medium of very low [H+] driving hydrolysis towards completion

Question 10

Does catabolism use or release ATP?

Answer 10

releases ATP = breakdown

Question 11

Does anabolism use or release ATP?

Answer 11

uses ATP = build up

Question 12

Redox reaction formula

Answer 12

E = i + iii

Question 13

How to do redox reactions…

Answer 13

Switch one of the half reactions so the product is opposite of the full formula product. This is the reducer. Switch the sign and this is your iii.

Question 14

When is delta e spontaneous with respect to 0

Answer 14

When E>0

Question 15

Energy of free gibbs formula

Answer 15

G=-nFE
do not forget negative sign

Question 16

Enzyme cofactors - What does CoA do? What is it derived from? What is the reactive part of it?

Answer 16

carrier of acyl groups
B5
Sulfhydril
be able to recognize it

Question 17

Enzyme cofactors - What does NAD+ (oxidizing agent - gets reduced) do? What is it derived from?

Answer 17

carry electrons
B3
be able to recognize it

Question 18

Enzyme cofactors - What does FAD2 (reducing agent) do? whatis it derived from?

Answer 18

carry electrons
B2
be able to recognize it

Question 19

What is the enzyme bound intermediate in Hydrolysis of ATP? Is this a nucleophile or electrophile?

Answer 19

acyl adenylate
electrophile

Question 20

What does the thiolate ion act as when it attacks the enzyme bound intermediate?

Answer 20

nucleophile

Question 21

In general, when ATP hydrolysis is coupled to an energy-requiring reaction, the actual reaction often consists of the transfer of a phosphate group from ATP to another substrate, rather than an actual hydrolysis of the ATP. Explain.

Answer 21

Hydrolysis of the ATP would result in the loss of most of the free energy as heat. In a transfer reaction, the gamma (third) phosphate of ATP is transferred to the reaction substrate to produce a high-energy phosphorylated intermediate, which can then form the product in an exergonic reaction

Question 22

What is the fate of acetyl CoA produced in beta oxidation?

Answer 22

Goes into krebs cycle where it is further oxidized to generate NADH and FADH2