Aerobic Respiration

• Mitochondria Diagram

  A) 70s ribosomes

  B) Cristae

  C) Mitochondrial DNA

  D) Intermembrane Space

  E) Matrix

  F) link reaction

  G) Krebs cycle

  H) NAD

  I) FAD

  J) Stalked Particles (ATP Synthase)

  K) ATP

  L) Outer Membrane

  M) partially permeable

  N) active

  O) pyruvate

  P) Inner Membrane

  Q) lipid

  R) impermeable

  S) small ions

  T) H^+

  U) Cristae

  V) Surface Area

  W) enzyme

  X) oxireductase enzyme

  Y) co-factors

  Z) proton

  [) co-enzymes

  \) matrix

  ]) intermembrane

  
• Mitochondria

  • Many reactions, involve substrate oxidation by electron or hydrogen (atom) removal
  • e-/H+ must be passed to electron carrier molecules; FAD, NAD + O_2

  Electron carriers

  • NAD: Dinucleotide w/ pentose sugar, ribose + bases adenine + nicotinamide (ring structure + accepts 2H atoms)
  • Exists in cells as oxidised NAD (lost two electrons)
  • NAD + 2H+ + 2e- → NADH + H+
  • Reversible reaction catalysed dehydrogenase; oxidoreductase enzyme
  • FAD: Dinucleotide w/ pentose sugar, ribose + bases adenine + flavine (derived from Vit B1)
  • FAD + 2H+ + 2e- → FADH_2
  • Reversible reaction catalysed dehydrogenase enzyme
  • Both NAD + FAD are coenzymes (non-protein compounds necessary for enzyme function)
  • O_2: Final electron acceptor in electron transport chain; reduced to water
  • O_2 + 4H+ + 4e- → 2H_2O
• Glycolysis Diagram

  A) phosphorylated

  B) 3C

  C) oxidised

  D) 4

  E) 2

  F) 2

  G) 1

  H) 2

  I) 2

  J) 2

  K) 4

  L) 2

  
• Link Reaction

  A) matrix

  B) pyruvate

  C) Oxidative carboxylation

  D) Coenzyme A

  E) ethanote

  F) Krebs

  G) 2

  H) 2

  I) 2

  J) 2

  
• Krebs Cycle

  A) link

  B) decarboxylated

  C) dehydrogenated

  D) decarboxylated

  E) dehydrogenated

  F) CO_2

  G) 2

  H) dehydrogenated

  I) 2

  J) CoA

  K) oxalocetic

  L) citric

  
• Oxidative Phosphorylation

  • Mitochondrial membrane (cristae), about protons + electron
  • Aims to synthesise ATP + re-oxidise NADH/FADH2 so prior stages can continue
  • Chemiosmosis
  • H^+ movement down conc gradient release energy
  • Energy from high-energy e-, raised to high energy by photosynthesis or respiration
  • Excited e- taken to ETC by reduced coenzymes NAD + FAD
  • Process
  • Reduced NAD + FAD arrive at ETC, oxidized release H; separates H^+ + e-
  • e-pass down ETC by oxidation redox reaction, release energy
  • Used to pump protons over inner mitochondrial membrane to intermembrane space, make electrochemical gradient
  • H^+ diffuse down gradient by facilitated diffusion cause conformational change in ATP synthase
  • Role of O_2
  • Final e- acceptor, combine w/ electrons, end of ETC + H^+ from reduced NAD + FAD
  • Make water; 4H^+ + 4e^- + O_2 → 2H_2O, enable more e- to move down ETC + ATP synthesis
  • Inhibited by cyanide + carbon monoxide
• ATP

  • ATP produced before ETC: 4 in glycolysis (2 used so NET 2) + 2 produced from 2 Krebs cycle turns (4 overall)
  • ATP produced in ETC (each reduced NAD = 2.5 ATP + each reduced FAD = 1.5 ATP):
  • Glycolysis: 2x reduced NAD = 5 ATP
  • Link Reaction: 2x reduced NAD = 5 ATP
  • Krebs Cycle: 6x reduced NAD = 15 ATP + 2x reduced FAD = 3 ATP
  • Overall respiration: 32 ATP
  • Efficiency: Theoretical yield of 32 for each glucose is rarely achieved; in fact, respiration is ~32% efficient
  • Some used moving H from reduced NAD in glycolysis or pyruvate to mitochondria by active transport
  • Some generates heat, to maintain a suitable body temp for enzyme-controlled reactions