Unit 2: Photosynthesis and Cellular Respiration

• Energy is the ability to do work.
• Thermodynamics is the study of the flow and transformation of energy in the universe.
• What are the two laws of thermodynamics?

  First law: Conservation of energy. Energy can be converted, but never created or destroyed.

  Second law: Entropy. Energy cannot be converted without some loss of usable energy.
• How do autotrophs get nourishment?

  They make their own food.
• How do heterotrophs get nourishment?

  They ingest food.
• Autotrophs are also known as producers, heterotrophs are also known as consumers.
• What is metabolism?


  All of the chemical reactions in a cell.
• What is photosynthesis?


  When light energy is converted to chemical energy.
• What is cellular respiration?

  When organic molecules are broken down for energy for the cell.
• Photosynthesis is an anabolic reaction, whereas cellular respiration is catabolic.
• What is ATP?


  The unit of cellular energy.
• What is the difference between catabolic and anabolic reactions?

  Catabolic reactions involve the breakdown of complex molecules into simpler ones, releasing energy. Anabolic reactions involve the synthesis of complex molecules from simpler ones, requiring energy.
• The bond between the second and third bond in an ATP is high in energy.
• What is the chemical equation for photosynthesis?

  6CO2 + 6H2O -> C6H12O6 + 6O2
• During the light-dependant reactions, light energy is converted to ATP and NADPH (chemical energy).
• During the light-independant reactions, ATP and NADPH are used to convert CO2 to sugar.
• What is the process of photosynthesis?

  1. Chloroplasts capture light energy.
  2. Light energy excites electrons in PS2.
  3. A water molecule splits - sends 1 electron into the ETC, H+ into the thylakoid space, and O2 as waste.
  4. The electron moves through a series of electron transporters to PS1.
  5. PS1 transfers the electrons to ferredoxin.
  6. Ferredoxin transfers the electron to NADP+, which then becomes NADPH.
• What are the three steps of the Calvin Cycle?

  1. Carbon fixation
  2. Reduction
  3. Regeneration
• What is the energy yield from glycolysis?

  2 ATP and 2 NADH
• What is the energy yield from the Krebs Cycle?

  6 CO2

  2 ATP

  8 NADH

  2 FADH2
• What is the energy yield for the electron transport chain of cellular respiration?

  32 - 34 ATP
• Alcoholic fermentation uses Pyruvate and NADH to make Ethanol, NAD+, and CO2.
• Lactic acid fermentation uses Pyruvate and NADH to make Lactic acid and NAD+.
• What does ferredoxin do?

  Reduces NAD+ to NADPH.
• What does the ATP synthase do?

  Makes ADP into ATP.
• What is the process of aerobic respiration?

  1. Glycolysis (glucose is split into two pyrvuate)
  2. Pyruvate oxidation (pyruvate loses one carbon)
  3. Acetyl-CoA formation
  4. Acetyl-CoA bind with four-carbon molecule
  5. Citric acid is formed
  6. Citric acid is broken back down to four carbon molecule
  7. Cycle repeats
• Which process does NOT occur in the mitochondria?

  Glycolysis
• Which is NOT a stage of cellular respiration?  

  Lactic acid fermentation
• What is produced when the electrons leave the ETC in cellular respiration and bind to the final electron acceptor for the chain?

  H2O
• What is different about C4 and CAM plants?

  They keep their stomata closed during the day to conserve water. CAM plants specifically allow CO2 to enter only at night.