Ch. 5: Energetics of Biological Systems Flashcards Preview

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Flashcards in Ch. 5: Energetics of Biological Systems Deck (17):
1

3 ways rate of rxn can be altered?

1) ⬆️ [reactants] (not practical/desirable)
2) ⬆️ temp (not practical)
3) Add catalyst (enzyme) (practical)

2

What is the 1st law of thermodynamics?

Energy can neither be created nor destroyed

3

What is the 2nd law of thermodynamics?

Entropy of the system & surroundings ⬆️ & attain max value at equilibrium

4

Exergonic vs endergonic rxns?

Exergonic: spontaneous, release energy

Endergonic: thermodynamically unfavorable

5

What is the equation for Gibbs free energy?

🔺G = 🔺H - T(🔺S)

6

🔺G* < 0 is seen in which type of rxns?

Spontaneous (exergonic) rxns

7

🔺G* > 0 is seen in which type of rxns?

Non-spontaneous (endergonic) rxn

8

🔺G* vs 🔺G?

🔺G* = standard free energy change at pH 7

🔺G = change in free energy

9

If 🔺H is a major contributor to a rxn, what does this mean about the rxn? (Enthalpy driven rxn)

Rxn involves ionic interactions, H bonding (heat has to be changed)

10

If 🔺S is a major contributor to a rxn, what does this mean about the rxn? (Entropy driven rxn)

Rxn involves hydrophobic/hydrophilic interactions

11

As Keq ⬆️, what happens to 🔺G*?

🔺G* ⬇️
(Tendency for rxns to occur ⬆️ spontaneously)

12

How many high energy bonds does ATP posses?

2

13

What type of 🔺G* does ATP have?

Large, negative free energy of hydrolysis

14

Rxn type: A ➡️ B

Rate eqn? Reaction order?

Rate = k[A]

1st order rxn (no collision needed)

15

Rxn type: A + B ➡️ C + D

Rate eqn? Reaction order?

Rate = k[A][B]

Second order rxn

16

Rxn type: A + A ➡️ D

Rate eqn? Reaction order?

Rate = k[A]^2

Second order rxn

17

What is the kinetic order of a rxn usually used to determine?

Molecularity of rxn (# molecules/ions that participate in rate determining step