Mitochondria

• Characteristics of mitochondria

  
  

  • DNA
  • Envelope
  • Divide by binary fission
• What is the key feature of the Outer membrane of mitochondria

  The main protein is porin which formes large aqueous channels.
• Components of inner membrane of mitochondrion

  • Electron transport chain
  • ATP synthase
  • Transport molecules
• What are the key features of the mitochondrial cristae

  • Increases membrane surface area
  • ATP synthase
  • Impermeable to most small ions
• Contents of mitochondrial matrix

  • Enzymes which catalyse Krebs cycle and fatty acid oxidation
  • Ribosomes
  • Mitochondrial DNA
• What are the main modes of action of ATP

  • Transport
  • Mechanical
  • Chemical
• How does the mitochondria use the oxidation of organic molecules

  Production of energy used for the synthesis of ATP [Glycolysis].
• How does the ETC generate energy

  Redox reactions
• What are the key features of the ETC.

  Made of multiprotein complexes with prosthetic groups. The proteins are reduced when they accept electrons and oxidised when they release their electron. The protein downhill has a higher affinity for the electron.
• Components of electron transport chain

  • Flavoprotein with flavin mononucleotide prosthetic group
  • Iron-sulphur proteins
  • Ubiquinone
  • Cytochromes with 4 organic rings around iron
  • Oxygen which picks up a pair of H+ to form water
• Which electron carrier releases electrons at a lower level

  FADH2
• Label the mitochondria

  h

  A) Glycogen granule

  B) DNA

  C) Cristae

  D) ATP Synthase

  E) Intermembrane space

  F) Inner membrane

  G) Outer Membrane

  H) Ribosomes

  I) Matrix

  
• How does ATP exhibit transport work

  ATP phosphorylates transport proteins in order to activate them.
• How does ATP exhibit mechanical work

  Phosphorylates motor proteins.
• What is a redox reaction

  A reaction which contains both oxidation [Loss of electrons] and reduction [Gain of electrons].
• What are prosthetic groups in the ETC

  Non-protein molecules which are essential for the catalytic functions of the ETC.
• What is the first protein in the ETC called

  Flavoprotein
• What is the prosthetic group for flavoprotein

  Flavin mononucleotide.
• What happens to the electronegativity as you travel down the ETC

  Increases
• What is the F0 of ATP synthase

  The H+ channel
• What is the F1 portion of ATP synthase

  ATP synthesis
• Which part of ATP synthase is F1


  The intracellular portion [head].
• What is cyanide

  A mitochondrial poison
• What is the pathology of cyanide poising

  Prevents electrons being passed from cytochromes. Inhibits ATP synthase as the ETC cannot function.
• What type of poison is 2,4-Dinitrophenol

  Mitochondrial
• What is the action of 2,4-Dinitrophenol

  Inner membrane becomes leaky to H+. The chemical gradient is not established as protons can diffuse across the membrane. No ATP is made.
• What is brown fat

  A specialised adipose tissue which provides warmth.
• What is white fat

  A specialised adipose tissue which is used as an energy storage.
• What does the mitochondria in brown fat do.

  Produces heat by using the thermogenin Hydrogen channel. Protons leak into the membrane causing heat to be released as no ATP is produced.
• What is released when the mitochondrial inner membrane is leaky to protons

  Heat.
• What is MERRF

  Myoclonic epilepsy and ragged-red fiber disease
• Describe how MERRF occurs

  It is a mitochondrial genetic disease. It is caused by a mutation in the mitochondrial DNA which affects the tRNA produced.
• What does MERRF cause

  Abnormal mitochondrial morphology.
• How does MERRF account for epilepsy

  Mitochondria are found mainly in the muscles and nerves.
• Label the ATP synthase and describe its function.

  Hydrogen ions move thorugh F0 causing the rotor and central stork to rotate. The stator keeps the catalytic portion [F1] stationary. The movement of Hydrogen ions provides energy for the phosphorylation of ADP to form ATP.

  A) Hydrogen ion

  B) ATP

  C) Phoshpate and ADP

  D) Central stork

  E) Rotor

  F) Matrix

  G) Intermembrane space

  H) Stator

  I) Catlytic portion

  J) F0

  K) F1