Bioenergetics/Metabolic Pathways

Question 1

Standard state requirements

Answer 1

1M reactants, 1M products, 1ATM for gases, 25 degrees C

Question 2

Difference between G0 and G0’

Answer 2

Prime is the biochemical standard state where we have the reaction done in water at 55.5M and at neutral pH of 7.0

Question 3

Negative delta G

Answer 3

Spontaneous Reaction (the amount of energy available to do work is higher in the products)

Question 4

Positive delta G

Answer 4

Non-spontaneous

Question 5

Delta G0 equation

Answer 5

= - 1.36log ([P]/[R])

= -RT log ([P]/[R])

The standard free energy change for a reaction is related to the equilibrium constant of the reaction

Question 6

Delta G equation

Answer 6

Delta G = Delta G0 + 1.36log ([P]/[R])

The “real” amount of energy available to a cell is related to the standard gibbs free energy and the equilibirum constant

Question 7

Delta G formula in terms of RT and ln

Answer 7

DeltaG = RTln([P]/[R]) - RTln([Peq]/[Req])

Question 8

DeltaG0 in terms of RT and ln

Answer 8

DeltaG0 = - RTln([Peq]/[Req])

Question 9

Answer 9

Question 10

Answer 10

Question 11

How do we determine the oxidation number of a carbon?

Answer 11

For every bond to H, subtract 2

For every single bond to O, N, S, or a halogen, add 1 [think SON Halogen]

Double bonds add 2

Triple bonds add 3

For every bond to another C, add 0.

Question 12

What formula do we use to find the Delta G0’ in calories

Answer 12

Delta G0’ = -nF(Delta)E0’

n = number of electron equivalents transferred in the reaction

F = 23.06 kcal/volt/equivalent of electrons (Faraday constant)

Question 13

Number of ATP per NADH

Answer 13

2.5/NADH

Question 14

Number of ATP per FADH2

Answer 14

1.5ATP/FADH2

Question 15

Why are ATP bonds high energy bonds?

Answer 15

Because they are between two negative phosphate groups which repel each other putting strain on the bond

Question 16

How do we get the energy from ATP?

Answer 16

You cannot just capture the exothermic heat caused by the hydrolysis reaction. You instead need to transfer the phosphates to carrier transfer metabolites or proteins (phosphoryl transfer reaction)

Question 17

S

Answer 17

Entropy

Question 18

H

Answer 18

Enthalpy

Question 19

P

Answer 19

High energy phosphate bond

Question 20

First law of thermodynamics

Answer 20

Conservation of energy - Energy in a system is always constant

Question 21

Second law of thermodynamics

Answer 21

Entropy is always increasing - We favor disorder

Question 22

Kelvins

Answer 22

Celsius + 273

Question 23

Types of work we can do with energy from ATP

Answer 23

1. Mechanical Work
2. Transport Work (Active Transport)
3. Biochemical Work

Question 24

Mechanical work

Answer 24

High energy phosphate group generates movement by changing the conformation of a protein

Example: ATP bound to myosin ATPase in muscle fibers is hydrolyzed, causing the myosin conformation to turn to a “cocked” position, ready to associate with the actin filament

Question 25

Transport Work

Answer 25

This is also called active transport Phosphates from the ATP used to act on the proteins in the plama membrane to cause a conformational change in the protein possibly pushing things against their concentration gradients

Question 26

Biochemical work

Answer 26

Energy-requiring reactions that use ATP and the bond energy to cause chemical reactions such as with detoxification of drugs

Question 27

What do all metabolic pathways have in common?

Answer 27

A negative gibbs free energy Unfavorable reactions are coupled with favorable ones

Question 28

Creatine Phosphate

Answer 28

Has a high energy phosphate group (~-10 kcal/mol) Amount of creatine in urine is a good determinant of muscle mass. Creatine in plasma is indicitive of kidney failure.

Question 29

Oxidation versus Reduction

Answer 29

LEO the lion says GER (loss of electrons = oxidation) (gain of electrons = reduction)

Question 30

The most energetic compounds are also the most?

Answer 30

Reduced

Question 31

H₂

Answer 31

Hydrogen molecule Two protons with two electrons

Question 32

H^.

Answer 32

Hydrogen atom one proton with one electron

Question 33

H^-

Answer 33

Hydrogen ion One proton with two electrons

Question 34

What does NAD⁺ accept?

Answer 34

H^- and is reduced to NADH | (aka two electrons)

Question 35

What does FAD accept?

Answer 35

2H^. and is reduced to FADH₂ (also carries 2 electrons)

Question 36

FADH₂ is derived from what?

Answer 36

Riboflavin (Vitamin B2)

Question 37

NADH is derived from what?

Answer 37

Niacin (Vitamin B3)

Question 38

What happens when the [NADH]/[NAD⁺] ratio is high?

Answer 38

The production of lactic acid via hydrogenation using NADH

Question 39

What happens under aerobic conditions to FADH₂ and NADH

Answer 39

They are re-oxidized in the mitochondria to NAD⁺ and FAD

Question 40

Why do we get more ATP production per NADH than we get from FADH₂

Answer 40

Because NADH is a stronger reducing agent