Biology Chp 5 & 6

• C3 Photosynthesis

  A biological process where photoautotrophs capture light energy and convert it into chemical energy.
• Mesophyll Cell 


  Plant cell type
• Chloroplasts 


  membrane-bound organelle, site of photosynthesis
• Chlorophyl 


  found in the thylakoids, absorbs light energy
• Stomata 


  pores in the surface of leaves
• Xylem 


  responsible for transporting water and minerals
• Light-dependant 


  Only occurs when light is present and in the Thylakoids. Purpose to generate high energy co-enzymes NADPH and ATP. Light energy spilts water into oxygen and hydrogen.
• Thylakoid 


  flattened SAC, location of the Light-dependant stage
• NADPH / NADP+


  A coenzyme
• ADP/ATP


  energy molecule, when loaded (ATP) it provides energy for cellular processes.
• INPUTS of Photosynthesis

  • 12 Water
  • 12 NADP+
  • 18 ADP+Pi
• Outputs for Photosynthesis

  • 6 Oxygen
  • 12 NADPH
  • 18 ATP
• Light-Independent Stage (Calvin Cycle) 


  Glucose if produced from carbon dioxide.

  Occurs in the stroma of the chloroplasts

  Does not require light

  Energised by ATP and NADPH
• Stroma 


  fluid substance makes up the interior of chloroplasts
• Inputs for the light-independent stage

  • 6 CO2
  • 12 NADPH
  • 18 ATP
• Outputs for the Light-independent Stage

  • C6H12O6
  • 6 H2O
• Rubisco 


  Key enzyme in the Light-independent stage.

  It can bind to CO2 (inorganic) and create 3-PGA (Organic)

  It can also bind to O2 and initaite Photorespiration
• Issue with Rubisco

  It can undergo Photorespiration, inhibiting Photosynthesis.

  It can impact a plants ability to grow, survive and reproduce.
• Factors that Influence Rubisco 


  Substrate Concentration - With more O2 present, it has a greater chance for the O2 to bind

  Temperature - Regular or Low temp, affinity to CO2 is higher. At High Temp the affinity for O2 is higher
• C4 Plants 


  Same Light-dependant Stage

  Independent has differences, it is separated into the bundle-sheath cell and the mesophyll cell.

  Which constantly pumps CO2 into the bundle-sheath. Minimising Photorespiration.
• CAM Plants

  Has the adaptation to separate the Photosynthesis steps over time.

  Opening their stromata at night to let CO2 in.

  Closing it in the day to prevent water loss.

  Uses more energy (ATP)
• Factors affecting the rate of photosynthesis 


  Light - intensity/amount

  Temperature & PH - Because of the enzymes, and their optimal

  CO2 Concentration - As if low, photorespiration can occur.
• CRIPSR-CAS9 affecting photorespiration 


  Can use it to somehow mimick the function of the CAM & C4 Plants to minimise the effects in C3 plants.
• Cellular Respiration 


  cells create usable energy in the form of ATP by breaking down glucose.
• Aerobic Cellular respiration 


  Glucose reacts with Oxygen to produce CO2, H2O and ATP

  Produces either 30 or 32 ATP per glucose

  Occurs in 3 stages.

  Glycolysis

  The Krebs cycle

  The Electron transport chain
• Mitochondria 


  site of the Krebs Cycle and Electron transport chain, to generate high energy molecules.

  The Inner membrane folds into Cristae which is where ETP occurs

  The Mitochondrial Matrix is where the Krebs cycle occurs.
• Glycolysis 


  First Stage

  Occurs in the cytosol

  Breaks down glucose to pyruvate.

  2 ATP is produced.

  Creates NADH
• Glycolysis Inputs 


  1 Glucose

  2 ADP+Pi

  2 NAD+ +2H+
• Glycolysis Outputs 


  2 Pyruvate

  2 ATP

  2 NADH
• The Krebs Cycle 


  Second Stage

  Occurs in the matrix

  Extracts energy from the acetyl-COA.
• Krebs Cycle Inputs 


  2 Acetyl-COA (from the 2 pyruvate)

  2 ADP+ 2 Pi

  6 NAD+ + 6H+

  2 FAD + 4H+
• Krebs Cycle Outputs 


  4 Carbon Dioxide

  2 ATP

  6 NADH

  2 FADH2
• Electron Transport chain 


  Third Process

  Occurs in the cristae

  The majority of ATP is produced

  Oxygen in required

  Kinetic Energy is created by enzymes spinning creating the ATP.

  The number of ATP depends to the NADH & FADH2
• Electron Transport Chain Inputs

  6 Oxygen + 12 H+

  26 or 28 ADP + 26 or 28 Pi

  10 NADH

  2 FADH2
• Electron Transport Chain Outputs

  6 H2O

  26 or 28 ATP

  10 NAD+ + 10H+

  2 FAD + 4H+