Laws and principles that describe the interchange between

1. Heat
2. Energy
3. Matter

Enthalpy is the change in heat (∆H).

1. -∆H = Heat is lost by a system
   • This is Favorable and Spontaneous
   • Ex- Forming weak interactions during protein folding
2. +∆H = Heat is gained by a system
   • This is Unfavorable and Nonspontaneous
   • Ex- Breaking weak interactions during protein folding

Entropy (S) is a measure of disorder

1. -∆S = System is more Ordered 
   • This is Unfavorable and Nonspontaneous
2. +∆S = System is more Disordered
   • This is Favorable and Spontaneous

Free Energy (∆G)

1. Tells how much energy is available for work. It is dependent of ∆H and ∆S
2. Allows you to assess Reaction Spontaneity
   1. -∆G is Spontaneous (Favors Products)
   2. +∆G is Nonspontaneous (Favors Reactants)

A + B = C + D

1. When ∆G = 0 the reaction is at equilibrium
2. When ∆G < 0, the reaction favors the Products (↑ C+D). Spontaneous
3. When ∆G > 0, the reaction favors the Reactants (↑ A+B). Non-spontaneous

1. ΔG = 0 at Equilibrium (no net change in [A], [B], [C], [D])
2. If ΔG < 0 (-ΔG) then ln Keq > 1
   • [C] and [D] Favored
3. If ΔG > 0 (+ΔG) then ln Keq < 1
   1. [A] and [B] Favored

1. Reduced Coenzymes (NADH, FADH2). AKA: Electron Carriers
2. High-energy Phosphate Compounds (ATP, GTP)

1. Many energy requiring (+ΔG) reactions must occur to sustain life
2. Cells couple highly favorable reactions (Large -ΔG) to energy requiring reactions (+ΔG) to force the +ΔG reaction forward
3. Cells use High Energy Biomolecules to couple these reactions
   • Energy liberated from the high energy biomoleule breakdown (-ΔG) is harnessed and used to drive the energetically unfavorable (+ΔG) reaction

Greatest Free Energy

1. PEP
2. 1,3-BPG 
3. ATP
4. UDP-glucose
5. Acetyl CoA
6. Glucose 6-Phosphate

Lowest Free Energy

11.1 Why is ATP considered the energy currency of the cell

11.2 How is ATP stable with its high energy capacity

11.1 Because it is intermediate in terms of available free energy. It is easily formed and easily used

11.2 Because it has such a high Energy of Activation.

• ATP can't spontaneously convert to ADP because of its high Energy of Activation.
• However, an enzyme can catalyze this reaction easily

Molecules are made from molecules that have more free energy

1. PEP and 1,3-BPG are created in the course of glucose breakdown.
2. The energy from these molecules is transfered (in combination with a phosphate) to ADP to form ATP

12.1. Bonds between phosphate groups in ATP are called phosphoanhydride bonds.

• When these bonds are hydrolyzed, energy is released because the products of the reaction (ADP and phosphate (Pi)) are more stable than the reactants (ATP and H2O)

13.1. What has phosphoric anhydride linkages?

13.2. What has phosphoric-carboxylic anhydride linkages?

13.3. What happens to phosphoric-carboxylic anhydride bonds

13.1. ATP

13.2. Acetyl Phosphate and 1,3-BPG

13.3. They are hydrolyzed and acetate comes off

1. ATP can transfer energy to enzymes (that then do work)
2. ATP can activate other molecules (of lower energy phosphate compounds)

1. Glucose enters the cell and is activated by ATP so it can't leave the cell
   • Glucose is now G-6-P
   • This is an energy transfer
2. G-6-P is activated by UTP to become UDP-Glucose
   • This is an energy transfer
3. UDP-Glucose adds G-1-P to Glycogen (and UDP pops off)
   • This is another energy transfer

15.1. What is an "electron shuttle"?

15.2. Give 2 examples

15.1. A molecule that transfers electrons from one molecule/reaction to another molecule/reaction

15.2. Electron Shuttles

1. NADH- NAD+ can be reduced (gain a hydride (1 H⁺ and 2 electrons)) to NADH
2. FADH2- FAD+ can be reduced (gain 1H⁺ and 1 electron and then gain another 1H⁺ and 1 electron) to FADH2

1. Electrons are transferred from molecules to NAD+ & FAD+ to form NADH & FADH2. These electrons come from glycolysis & the TCA Cycle
2. NADH & FADH2 go to the ETC & transfer their electrons to proteins in the ETC
3. Through a series of redox reactions, the ETC creates a H+ gradient
4. The energy of the H+ gradient drives ATP Synthase to make ATP

OIL RIG

1. NAD+ and FAD+ are the oxidized forms. When they gain electrons they are reduced to NADH and FADH2
2. NADH and FADH2 are the reduced forms. When they lose electrons they are oxidized to NAD+ and FAD+

1. NAD+/NADH and NADP+/NADPH
2. FAD/FADH2 and FMN/FMNH2
3. Coenzyme Q (in ETC)
4. Lipoic acid (has free SH groups)
5. Vitamin C (has electrons)
6. Tetrahydrobiopterin

19.1. What is the redox potential?

19.2 What does it tell you about electron flow?

19.1. The tendency of electrons to be transferred from 1 molecule to another (Standard Reduction Potential (E))

19.2 Electrons flow spontaneously from a molecule with a more negative E to a molecule with a more positive E