Bioenergetics/Metabolic Pathways Flashcards Preview

MSK Week 1 > Bioenergetics/Metabolic Pathways > Flashcards

Flashcards in Bioenergetics/Metabolic Pathways Deck (40):
1

Standard state requirements

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

2

Difference between G0 and G0'

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

3

Negative delta G

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

4

Positive delta G

Non-spontaneous 

5

Delta G0 equation

= - 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 

6

Delta G equation

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 

7

Delta G formula in terms of RT and ln

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

8

DeltaG0 in terms of RT and ln

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

9

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11

How do we determine the oxidation number of a carbon?

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.

12

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

Delta G0' = -nF(Delta)E0'

n = number of electron equivalents transferred in the reaction

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

13

Number of ATP per NADH

2.5/NADH

14

Number of ATP per FADH2

1.5ATP/FADH2

15

Why are ATP bonds high energy bonds?

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

16

How do we get the energy from ATP?

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)

17

S

Entropy

18

H

Enthalpy

19

P

High energy phosphate bond

20

First law of thermodynamics

Conservation of energy - Energy in a system is always constant

21

Second law of thermodynamics

Entropy is always increasing - We favor disorder

22

Kelvins

Celsius + 273

23

Types of work we can do with energy from ATP

1. Mechanical Work

2. Transport Work (Active Transport)

3. Biochemical Work

24

Mechanical work

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

25

Transport Work

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

26

Biochemical work

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

27

What do all metabolic pathways have in common?

A negative gibbs free energy

Unfavorable reactions are coupled with favorable ones

28

Creatine Phosphate

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.

29

Oxidation versus Reduction

LEO the lion says GER

(loss of electrons = oxidation)

(gain of electrons = reduction)

30

The most energetic compounds are also the most?

Reduced

31

H2

Hydrogen molecule 

 

Two protons with two electrons

32

H.

Hydrogen atom 

one proton with one electron 

33

H-

Hydrogen ion

 

One proton with two electrons

34

What does NAD+ accept?

H- and is reduced to NADH

(aka two electrons)

35

What does FAD accept?

2H. and is reduced to FADH2

(also carries 2 electrons)

36

FADH2 is derived from what?

Riboflavin (Vitamin B2)

37

NADH is derived from what?

Niacin (Vitamin B3)

38

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

The production of lactic acid via hydrogenation using NADH

39

What happens under aerobic conditions to FADH2 and NADH

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

40

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

Because NADH is a stronger reducing agent