topic 5

• aerobic respiration is the process by which glucose is converted into energy (ATP)
• aerboic respiration equation - glucose + oxygen -> carbon dioxide + water
• anaerobic respiration is when there is no oxygen present and this equation produces lactic acid
• anaerobic respiration equation -

  glucose -> lactic acid
• Glycolysis - the first stage of aerobic respiration which happens in the cytoplasm
• link reaction - the second process following glycolysis. this takes place in the matrix of the mitochondria
• the Krebs cycle is the third process of aerobic respiration and takes place in the matrix of mitochondria
• oxidative phosphorylation is the process in which ATP is synthesised via chemiosmosis in the electron transport chain which takes place on the inner membrane of the mitochondria
• the oxidative phosphorylation process:

  1. 2 reduced NAD and 2 reduced FAD ions carry hydrogen ions and electrons to the electron transport chain on the inner mitochondrial membrane
  2. Electrons are carried from one electron carrier to the next. Electrons move through the protein carriers as well as hydrogen ions which are pumped across due to the concentration gradient
• the oxidative phosphorylation process - after pumping of electrons and hydrogens:

  3. Hydrogen ions have been pumped through the carriers into the outer membrane space where they go back down the concentration gradient though ATP synthase

  4. The energy created synthesises ATP through the fusing of ADP and Pi

  5. the hydrogen binds to the negatively charged oxygen ions to produce water
• if there is no oxygen then only glycolysis can take place
• in animals: reduced NAD and NAD cycling

  glucose -> pyruvate-> lactate
• in plants: reduced NAD and NAD cycling

  glucose -> pyruvate -> ethanal -> ethanol
• chloroplasts contain stacks of thylakoid membranes called "grana" - these contain photosynthetic pigments such as chlorophyll
• light dependant stage - occurs in the thylakoid membrane of the chloroplasts and is made of the two complexes - PS1 and PS2
• Cyclic phosphorylation -

  involves PS1

  produces ATP

  electrons are returned to the photosystem - cyclic
• Non-cyclic phosphorylation -

  involves both PS1 and PS2

  produces both ATP and reduced NAD

  electrons are obtained from water and are used to replace those lost in PS2
• cyclic phosphorilation:

  1. a photon of light hits a chlorophyll molecule
  2. electrons become excited and are taken by the electron acceptor
  3. electrons are passed along the etc as energy is released ATP is synthesised
  4. electrons return to PS1
• non-cyclic phosphorylation: part 1

  1. a photon of light hits a chlorophyll molecule
  2. electrons become excited and are taken by the electron acceptor
  3. electrons are passed along the etc as energy is released ATP is synthesised
  4. electrons return to PS1
• non-cyclic phosphorylation: part 2

  1. photolysis - water dissociates into hydrogen and hydroxide ions to replace lost electrons in PS2
  2. electrons become excited and are taken up by an electron acceptor, passed along an electron chain to NADP
  3. OH ions react with each other forming oxygen and water
• rubisco - reacts with carbon dioxide in the krebs cycle

  ribulose bisphosphate carboxylase
• light dependant stage takes place in the fluid-filled region surrounding the thylakoid membrane - "stroma"
• limiting factors - controls the rate of reaction
• light dependant stage:

  1. carbon dioxide diffuses in and reacts with ribisco and an intermediate molecule is formed
  2. this splits into 2 GP molecules
  3. (reduced NADP becomes NADP and ATP becomes ADP + Pi)
  4. 2 GALP molecules are formed
  5. some GALP molecules escape to make glucose to become organic compounds
  6. (2ATP become 2ADP + Pi)
  7. RUBP is formed
• at the end of the electron transport chain oxygen becomes reduced and forms water molecules with hydrogen ions
• glycolysis 


   glycolysis

  
• krebs cycle

  krebs cycle - 6 carbon molecule

  
• krebs cycle

  krebs cycle