Chapter 9.2 - Respiration

Question 1

Respiration

Answer 1

the requirement of O2 to oxidize molecules to produce energy.
*diagram

Question 2

Citric Acid Cycle (Tricarboxylic Acid Cycle)

Answer 2

1. Start with a 3 carbon compound (pyruvate)
2. Decarboxylation of pyruvate (loss of CO2)
   - acetyl: coenzyme A
   - with complete oxidization of pyruvate, you lose 3 CO2
   - Electrons go to NADH
3. The key thing of TAC cycle is the formation of NADH.
   - FAD= flavin adenine dinucleotide (oxidized form) add electrons and it will become reduced NADH2

Question 3

TCA/Krebs Cycle (5)

Answer 3

1. Fully oxidizes pyruvate (releases CO2 waste)
2. Reduce NAD+ and replace with a lot of NADH
3. Produces a little ATP (used by cell to derive reactions forward)
4. Produces a little FADH2
5. Cycle: regenerating 4 carbon starting molecule

Question 4

Redox reactions

Answer 4

• see example*
• Mitochondrial electron transport chain (ETC) oxidizes NADH (FADH2) to generate a proton (H+) gradient to make ATP.
• ETC’s work via series of connected redox reactions

Question 5

Electron Transport Chain diagram is super important

Answer 5

1. Binds NADH: Oxidation e- passed to carrier and protons are moved across the membrane
2. Complex 3: OH2 binds its oxidized e- to cytochrome C. H+ is pumped across the membrane.
3. Complex 4: binds cytochrome C, accepts the electrons, passed via carriers ultimately onto O2.

Question 6

Mobile Carriers

Answer 6

1. Q-Ubiquinone (in membrane)
2. Cytochrome C- protein with bound cytochrome (intermembrane space)
   * proton pumping mechanism: it pumps protons out of the membrane matrix into the membrane space.

Question 7

Proton Pumping Across a Membrane

Answer 7

look at diagrams in notes

Question 8

Experiment to test the mechanism for ATP Synthesis (3)

Answer 8

• diagram*
• Over time, ATP synthesis increases, but after a period of time it levels off.
• When it levels off the rxn is saturated
• There is a link between the proton gradient and ATP Synthesis

Question 9

Chemiosmotic Theory

Answer 9

Electron Transport and ATP Synthesis are coupled by a proton gradient across the mitochondrial membrane.
This theory was not taken seriously until years after it was proposed.

Question 10

ATP Synthase: Chemiosmotic Mechanism

Answer 10

• Proton gradient used to work like water using a turbine to make energy.
• ATP Synthase uses the proton gradient’s movement of protons to drive the production of ATP.
• Movement of stalk/turbine causes a conformational change in ATP Synthase, forcing inorganic phosphate to react.