CELLULAR RESPIRATION

• Aerobes: require o2 for cellular respiration
• Anaerobes: does not require o2 for cellular respiration
• Glycolysis


  Occurs in the cytosol of the cytoplasm. Breaks down glucose into 2 Pyruvates (3C), where ADP + Pi and NAD+ are loaded using the exogonic energy released from splitting the glucose molecule, making NADH and ATP.

  Note, some organisms rely on glycolysis as their sole source of energy.
• Too much pyruvate is toxic
• GLYCOLYSIS INPUTS AND OUTPUTS

  INPUTS- OUTPUTS-

  glucose (1) > pyruvate (2)

  ATP (2) > ADP (2) + Pi (2)

  ADP (4) + Pi (4) > ATP (4)

  NAD+ (2) > NADH (2)
• PREP STEP


  Occurs in cytosol of cytoplasm immediately after glycolysis.

  Pyruvate+CoEnzymeA+NAD+ ------> AcetylCoA+CO2+NADH
• Chemosynthetic autotrophs: Synthesise their carbon compounds from inorganic materials, using energy derived from chemical processes.
• Heterotrophs: Reliant on intake and digestion of organic molecules from external sources. (i.e. humans.)
• Mitochondria

  The site of aerobic respiration. Concentrations differ between cells according to specific energy needs (i.e. muscle cells, where a lot of ATP is needed, would have more mitochondria than rbc, where none are found.)
• Mitochondria

  lable

  A) Matrix

  B) Outer Membrane

  C) Ribosome

  D) Cristae

  E) Inner-membrane Space

  F) mtDNA

  
• Krebs Cycle

  Occurs in mitochondrial matrix

  Uses AcetylCoA made from pyruvate in prep step.

  
  

  Inputs: Outputs:

  AcetylCoA CO2

  NAD+ NADH

  FAD FADH2

  ADP+Pi ATP
• Aerobic Cellular Respiration


  C6H12O6+6O2------>6CO2+6H2O
• Electron Transport Chain.

  1. Occurs in the Inner-membrane space of mitochondria

  Electrons (from NADH and FADH2) are transferred through protein complexes in the electron transport chain, powering the active transport of protons from the mitochondrial matrix into the intermembrane space.
• Electron Transport Chain

  2. The proton concentration within the IMS increases, creating a steep concentration gradient.

  These protons travel through ATP synthase to reach equilibrium, creating kinetic energy that powers the reaction ADP + Pi to ATP.

  Oxygen acts as the terminal acceptor, which blinds to protons and electrons to form water. Oxygen is, therefore, required for the electron transport chain to proceed.
• Electron Transport Chain


  Inputs:

  O2 > H2O

  NADH > NAD+

  ADP+Pi > ATP

  FADH2 > FAD
• GLYCOLYSIS: 2 ATP

  KREB CYCLE: 2 ATP

  ETC: 26-28 ATP

  TOTAL: 30-32 ATP
• Anaerobic Cellular Respiration occurs when no oxygen is present to become the electron acceptor terminal. Both processes occur in cytosol of cytoplasm.

  The net output of ATP is 2, where the energy is still trapped within the bonds of the by-products (ethanol and lactic acid).
• ALCOHOLIC FERMENTATION

  Many Micro-organisms use this for ATP production.

  Yeast and Plants

  Converts potentially toxic Pyruvate with NADH (both from glycolysis) into CO2 and Acetyladehyde, which is turned into ethanol.

  No additional ATP is made, so the net output is 2 ATP.

  C6H12O6 + 2ADP+Pi ---------> Ethanol + CO2 + 2 ATP
• LACTIC ACID FERMENTATION

  Occurs in animal cells that respire anaerobically to generate a short burst of energy or if not enough oxygen is available. This can't be sustained for too long as lactic acid build up is toxic.

  C6H12O6 + 2ADP+Pi ----------> CO2 + Lactic acid + 2ATP
• lactic acid fermentation

  label

  A) glucose

  B) NAD+

  C) NADH

  D) NADH

  E) NAD+

  F) ADP+Pi

  G) ATP

  H) pyruvate

  I) lactic acid

  J) glycolysis

  K) NAD+ regeneration

  
• alcoholic fermentation

  label

  A) glucose

  B) NAD+

  C) NADH

  D) ADP+Pi

  E) ATP

  F) Pyruvate

  G) CO2

  H) ACETALDEHYDE

  I) NADH

  J) NAD+

  K) Ethanol

  L) Glycolysis

  M) NAD+ Regeneration

  
• Comparing Aerobic vs Anaerobic CR

  • Aerobic involves the complete breakdown of glucose into 30-32 ATP, whereas anaerobic only partially breaks down glucose, producing 2 ATP where the rest of the energy is still stored within the bonds of by-products.
  • Oxygen vs No Oxygen
• Temperature

  Increase heat increases the kinetic energy in the system, causing more frequent collisions between molecules and thus increasing rate of reaction. However, at temperatures beyond the zone of tolerance, enzymes denature and the process ceases.
• Glucose

  Photosynthetic cells have a renewable source of glucose. A saturation point will be met where enzymes are at maximum capacity. Excess glucose can be stored as starch or glycogen (animals). If little glucose, lipids and proteins will be used for energy.
• Oxygen

  Affects the type of CR process carried out. More oxygen increases rate of CR as it is needed in the ETC. However, a saturation point is met where enzymes are saturated.
• Krebs Cycle

  label

  A) Pyruvate

  B) CO2

  C) NAD+

  D) NADH

  E) NADH

  F) NAD+

  G) AcetylCoA

  H) 6C

  I) CO2

  J) 5C

  K) NAD+

  L) NADH

  M) NAD+

  N) NADH

  O) CO2

  P) 4C

  Q) ADP+Pi

  R) ATP

  S) FAD

  T) FADH2

  U) Oxaloacetate

  
• Krebs cycle

  label

  A) Pyruvate

  B) CO2

  C) NAD

  D) NADH

  E) AcetylCoA

  F) 6C

  G) CO2

  H) NAD+

  I) NADH

  J) 5C

  K) NAD+

  L) NADH

  M) CO2

  N) ADP+Pi

  O) ATP

  P) 4C

  Q) FAD

  R) FADH2

  S) NAD+

  T) NADH