Chapter 13: Energy regeneration in mitochondria

Question 1

• Morphology of mitochondria

Answer 1

• adaptable in location, shape and number
• 2 mem layers w/ larger intermembrane space between them
  • inner mem. has embedded proteins that carry out aerobic cellular respiration (use of oxygen) -> ATP
  • The inner mem. folds in on itself to create pockets called cristae.
  • The inner/central space of mitochondria is called the matrix

Question 2

• Know what purpose prosthetic groups serve in the ETC and provide examples

Answer 2

• Most pieces of etc use metal atoms, iron as e- acceptors
• bound by heme (PG that binds iron)
• Heme groups, named because found in hemoglobin in RBC’s
• iron atom in hemoglobin binds O2 rather than e-
• Cytochromes are heme-bearing proteins that make up majority of e- carriers in the ETC

Question 3

• Be able to describe the mechanism of oxidative phosphorylation and how electrons move through the ETC

Answer 3

• ATP is generated in inner mito. mem. by OP that is carried out by etc & chemiosmosis
• ETC made up of 4 multiprotein complexes (complexes I-IV)
• Each complex has prosthetic group, a non-protein component that accepts the high energy e- from NADH & FADH2
• W/ each handoff down chain, e- fall to a lower energy state releasing small amount of energy
• This energy used to pump H+ across inner mem. to create proton gradient “STEP-WISE” ENERGY RELEASE
• proton gradient is used by ATPase synthase -> ATP from ADP = chemiosmosis
• In the last step, the energy depleted e- are passed to O2 to form water

Question 4

• Know how and why a proton gradient forms (and the location it forms in)

Question 5

• Know the mechanism of chemiosmosis and the function the proton gradient serves

Answer 5

• Movement down the gradient produces energy which ATP synthase uses to convert ADP to ATP
- 1 H+ transported= 1 ATP made

Question 6

• Know the purpose/function of ATP synthase

Answer 6

• ATP synthase is an ion channel which opens and allows H+ to flow down their concentration gradient

Question 7

• Know the net outcome of the ETC and why there are discrepancies in the net amount

Answer 7

• either 36-38 molecules of ATP produced ( 2 from g, 2 from cac, 32-34 from op)
• There are discrepancies in the net amount because it depends on which carrier inside the matrix binds e- shuttled from cytoplasm.