Mitochondria

• Highly metabolically active cells have more mitochondria (up to 20% of total cell volume) with longer and more densely packed cristae, to hold more ETC and ATP synthase
• Mainly located in areas of cell where ATP demand is high or can be moved around cell by microtubules of cytoskeleton to where demand is high
• Many reactions, like respiration, involve substrate oxidation by electron or hydrogen (atom) removal, e-/H+ must be passed to electron carrier molecule; FAD (Flavine adenine dinucleotide), NAD (Nicotinamide adenine dinucleotide) and Oxygen
• NAD: Dinucleotide with pentose sugar, ribose, and bases adenine and nicotinamide (ring structure and accepts 2H atoms) exists in cells as oxidised NAD (lost two electrons) - NAD + 2H+ + 2e- → NADH + H+ (may also be written as reduced NAD); reversible reaction catalysed dehydrogenase (oxidoreductase enzyme)
• FAD: Dinucleotide with pentose sugar, ribose, and bases adenine and flavine (derived from Vit B1) - FAD + 2H+ + 2e- → FADH_2 (may be written as reduced FAD); reversible reaction catalysed dehydrogenase enzyme, also both NAD and FAD are coenzymes (non-protein compounds necessary for enzyme function)
• Oxygen: Final electron acceptor in electron transport chain; reduced to water, O_2 + 4H+ + 4e- → 2H_2O
• 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