11 - Bioenegetics Part 2 and ETC and OP Part 1

• hydrolytic; phosphate

ADENOSINE TRIPHOSPHATE (ATP)

• regarded as the energy currency of the cell

• powers most cellular work. How?

  • __________ cleavage of the high energy ___________ bonds is coupled with an energy-requiring (non-spontaneous) reaction

• negative (−); spontaneous

COUPLING OF REACTIONS

• biochemical reactions that are thermodynamically unfavorable are coupled with those that are favorable

• the aim of coupling is to attain a __________ (_) ΔG°’ thereby rendering the overall reaction ________________
  
  

• an important thermodynamic fact:

  • the overall ΔG°’ for a chemically coupled series of reactions is equal to the sum of the ΔG°’ of the individual steps

• AUTOTROPHIC

  • photophosphorylation

• HETEROTROPHIC

  • substrate-level

  • oxidative

HOW DO CELLS MAKE ATP?

• ____________ METABOLISM

  • photosynthesis through ___________________

• ____________ METABOLISM

  • cellular respiration (aerobic and anaerobic)

    • ____________ phosphorylation

    • _________ phosphorylation

TEST YOURSELF

1. The standard free energy change (ΔG°') and the actual free energy change (ΔG) are always equal.

2. Coupling ATP hydrolysis to an unfavorable reaction can make the overall process thermodynamically favorable.

3. Oxidation always involves the gain of electrons.

4. ATP hydrolysis is an example of an endergonic reaction.

5. ATP is the highest-energy phosphate compound found in cells.

CELLULAR RESPIRATION

1. digestion

2. acetyl CoA

   • glycolysis; fatty acid oxidation

3. acetyle CoA

   • Krebs cycle; electron transport chain

STAGES OF CELLULAR RESPIRATION

1. _________ of food polymers

2. production of ______________

   • ___________ and/or _____________

3. oxidation of ___________ to CO2 and H2O

   • ____________ and ___________________

4 PATHWAYS OF RESPIRATION

1. GLYCOLYSIS

   • __________ → __________ + __________ + __________

     • __________ → __________

2. KREBS CYCLE

   • __________ → __________ + __________ + __________ + __________

4 PATHWAYS OF RESPIRATION

3. ELECTRON TRANSPORT CHAIN

   • passage of electrons from __________ and __________ to O₂, H₂O and __________

4. ATP SYNTHESIS

   • involves the enzyme __________ that synthesizes ATP

ELECTRON TRANSPORT CHAIN

a series of reaction wherein electrons and H+ from NADH and FADH2 are passed to intermediate carriers before being accepted ultimately by O2 to produce H2O

downhill

• lowest; highest

ELECTRON TRANSPORT CHAIN

electrons flow “_________” creating energy (as ATP) from NADH and FADH2

• _________ standard reduction potential to __________ standard reduction potential

PROTEIN COMPLEXES

• NADH dehydrogenase

• succinate CoQ oxidoreductase

• bc1 complex

• c oxidase

_________________ IN ETC

• intermediate electron carriers embedded in the inner mitochondrial membrane
  
  

• Complex I - ______________________

• Complex II - _________________________

• Complex III - cytochrome __________________

• Complex IV - cytochrome ______________

2. electron flow through complexes ___, ___ and ___ results to transfer of protons (H+) from the ___________ to the ___________ space.

3. _________ transfers electrons via Complex ___. Unlike the other complexes, no proton transfer occurs here.

4. Higher [H+] concentration in the intermembrane space generates the ___________________ (pH gradient + membrane potential).

5. ___________ are ultimately accepted by O2 in Complex IV to generate H2O.

How many protons pumped during NADH oxidation and FADH2 oxidation, respectively?

________________________

• an enzyme complex containing the catalytic site for the synthesis of ATP

• subunits:

  • F_o – ___________________ unit

  • F₁ – where ____________ occurs

ATP SYNTHASE COMPLEX

reaction involved:

• ___ + ___ + ___ ⇌ ___ + ___

  • (ΔG°’ = +30.5 kJ/mol)

CHEMIOSMOTIC HYPOTHESIS

_________________________________

• proposed by Peter Mitchell in 1961

• electron transport and ATP synthesis are coupled by a proton gradient (pH gradient and membrane potential) across the inner mitochondrial membrane.

CHEMIOSMOTIC HYPOTHESIS

_______________________________

• upon creation of a proton gradient, protons flow back to the matrix to equalize charge distribution and by doing so, drives synthesis of ATP by ATP synthase complex. How?

• proton; shape; ATP synthase

• ADP; Pi

• proton-motive

ATP FORMATION

• ________ flow effects a change in the ________ of the ___________

• change in shape enables binding of ___ and ___ to form ATP.

• “_____________ force”

• 4

• 2

• III and IV

ATP YIELD FROM OP

• number of protons pumped per complex:

  • Complex I and III= _ protons each

  • Complex IV = _ protons

• upon oxidation of NADH, 10 protons are pumped

• for the oxidation of FADH2 , only 6 protons are pumped

  • FADH2 enters Complex II which does not pump protons. Thus, electrons from FADH2 pass through Complex ___ and ___ only.

• 4

• 10/4 = 2.5

• 6/4 = 1.5

ATP YIELD FROM OP

• If _ protons are needed to synthesize one mole of ATP

  • For each NADH:

    • ___________ ATPs are produced

  • For each FADH2 :

    • ___________ ATPs are produced