Electron Transport Chain (Aerobic Respiration) and Chemiosmosis

Question 1

constitutes the oxidation of electron donors NADH and FADH₂ causing both to lose electrons. The electron transport chain uses these electrons as energy to induce an electrochemical gradient. This gradient is then used to reattach inorganic phosphate groups to ADP to re-form ATP.

Answer 1

Oxidative Phosphorylation

Question 2

Occurs inside the inner mitochondrial membrane. It involves enzyme complexes/integral membrane proteins in a series of redox reactions with NADH and FADH₂, to transport hydrogen ions (H⁺) into the intermembrane space. This creates a proton gradient that supplies necessary energy for the production of ATP and water.

Answer 2

Electron Transport Chain

Question 3

The process of inducing an electrochemical gradient through a biological membrane that causes ions to emigrate from the two sides of the membrane.

Answer 3

Chemiosmosis

Question 4

• complex 1
• Receives e- and protons (H+) from NADH (oxidizes NADH)
• The electrons are transported to ubiquinone (Q), reducing it to ubiquinol
  *(4) H+ are released to the IMS

Answer 4

NADH dehydrogenase

Question 5

Complex II

• Receives e- from FADH2
• No H+ are transported to the IMS

Answer 5

Succinate Dehydrogenase

Question 6

Coenzyme Q (Q)

*mobile lipid-soluble molecule
* Receives e- from Complex I and Complex II
* Transports e- to Complex III

Answer 6

ubiquinone

Question 7

Complex III

• Receives e- from Q
• Transports (4) H+ to the IMS

Answer 7

Cytochrome c reductase /Cytochrome bc1 complex

Question 8

Complex IV

• Receives e- from cyt c one by one
• Transports some H+ (2?) to the IMS
  *Allows the 2e-to bond with 2H+ and 1/2O2 to form H20

Answer 8

Cytochrome c oxidase/cytochrome a3 complex

Question 9

Binds ADP with Pi to form ATP through ox-phos ATP molecules formed are found in the matrix

Answer 9

ATP synthase

Question 10

how does chemiosmosis happen

Answer 10

Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the matrix to the intermembrane spase. The pumping establishes a proton (H+) gradient. After the gradient is established, protons diffuse down the gradient through a transport protein called ATP synthase, producing ATP per 3 H+ molecule that diffused

Question 11

How much ATP does NADH and FADH2 produce theoretically

Answer 11

NADH - 3 (since it goes through 3 complexes that pumps H+)
FADH2 - 2 (since it goes through 2 complexes that pumps H+)

Question 12

How much ATP does NADH and FADH2 produce if there is a leaky complex

Answer 12

NADH - 2.5
FADH2 - 1.5

Question 13

How much ATP does NADH produce with glycolysis-NADH problem (NADH produced during glycolysis needs ATP to be transported inside the matrix.)

Answer 13

NADH - 3-1 = 2

Question 14

How many ATP does NADH produced if there is a leaky complex and glycolysis-NADH problem

Answer 14

2 NADH - 1.5 per NADH
8 NADH - 2.5 per NADH
2 FADH2 - 1.5 per NADH

Question 15

How many ATP molecules are produced by aerobic respiration?

Answer 15

30-38

(38 – theoretical/ideal yield)
(36 – Glycolysis-NADH problem)
(32 – leaky complexes)
(30 – leaky complexes + Glycolysis-NADH problem)

Question 16

a multifunctional protein, acting as an electron carrier in the electron transport chain(ETC), where it shuttles electrons from bc1complex to cytochrome c oxidase (COX), and as a trigger of type II apoptosis when released from the mitochondria.

Answer 16

cytochrome c