Shared Flashcard Set

Details

Biochem 38-39 Bioenergetics
Biochem, bioenergetics, thermodynamics
22
Biochemistry
Professional
09/21/2010

Additional Biochemistry Flashcards

 


 

Cards

Term
1. What is thermodynamics
Definition

Laws and principles that describe the interchange between

  1. Heat
  2. Energy
  3. Matter
Term
2. What is enthalpy? When does it occur? Give examples
Definition

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
Term
3. What is entropy?
Definition

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
Term
4. What is Free Energy?
Definition

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)
Term
5. What happens to a reaction (A + B = C + D) when 1) ∆G = 0, 2) ∆G < 0, 3) ∆G > 0
Definition

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
Term
7. Relationship between ΔG & Keq for the reaction A + B = C + D
Definition
  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
Term
8.1. What are High Energy Biomolecules
Definition
1. Energy shuttles that move energy to reactions that need it
Term
9. What 2 classes of biomolecules serve as High Energy Biomolecules (AKA Energy Transfer Molecules)?
Definition
  1. Reduced Coenzymes (NADH, FADH2). AKA: Electron Carriers
  2. High-energy Phosphate Compounds (ATP, GTP)
Term
8.2. How are High Energy Biomolecules used in life
Definition
  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
Term
10. Order the High Energy Phosphate Compounds in order from greatest to least free energy
Definition

Greatest Free Energy

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

Lowest Free Energy

Term

11.1 Why is ATP considered the energy currency of the cell

 

11.2 How is ATP stable with its high energy capacity

Definition

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
Term
How is ATP formed?
Definition

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
Term
12.1. Describe the high energy bonds in ATP
Definition

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)
Term

13.1. What has phosphoric anhydride linkages?

 

13.2. What has phosphoric-carboxylic anhydride linkages?

 

13.3. What happens to phosphoric-carboxylic anhydride bonds

Definition

13.1. ATP

 

13.2. Acetyl Phosphate and 1,3-BPG

 

13.3. They are hydrolyzed and acetate comes off

Term
12.2. What reactions can ATP participate in
Definition
  1. ATP can transfer energy to enzymes (that then do work)
  2. ATP can activate other molecules (of lower energy phosphate compounds)
Term
14.1. Explain the principle of coupled energy transfer
Definition
Using a molecule of high energy and transfering it to another molecule (of lower energy) to make it reactive
Term
14.2. Explain making glycogen with coupled energy transfer
Definition
  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
Term

15.1. What is an "electron shuttle"?

 

15.2. Give 2 examples

Definition

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
Term
16. What do NADH and FADH2 electron shuttles do? (Where are they created and where do they go?)
Definition
  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
Term
18. NAD+, NADH, FAD+, FADH2: which are oxidized and which are reduced
Definition

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+
Term
17. What are the redox cofactors we care about
Definition
  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
Term

19.1. What is the redox potential?

 

19.2 What does it tell you about electron flow?

Definition

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

Supporting users have an ad free experience!