GenBio Q2Q2

• When did the Great Oxygenation Event (GOE) occur?

  1. 1-2.4 billion years ago
• How did cyanobacteria affect the atmosphere?


  It released oxygen, changing the anoxic atmosphere
• What did the presence of oxygen on Earth enable?

  The evolution of aerobic respiration and high life forms
• What are the roles of plants in the ecosystem?

  • Provides oxygen
  • Consumes CO₂
  • Food source for organisms
  • Generates energy
  • Produces fibers and materials
• What does the arrow in a chemical equation represent?

  Reactants transforming into products
• What is the role of oxygen in cellular respiration?

  It is the last electron acceptor
• What is anaerobic respiration?

  Respiration that does not require oxygen
• What type of reactions does respiration involve?

  Catabolic and exergonic reactions
• What type of process is photosynthesis?

  Anabolic and endergonic process
• How does light move?

  In waves called photons
• What do photons carry?

  Energy
• How does wavelength relate to energy?

  Longer wavelength means lower energy
• What is the range of visible light?

  400-700 nm
• Why is visible light important for photosynthesis?


  It provides the right energy for biological reactions
• What happens to proteins when exposed to extreme conditions?

  They undergo denaturation
• What absorbs light in plants?


  Pigments
• What is the primary pigment for photosynthesis?

  Chlorophyll-a
• What colors of light does chlorophyll-a absorb?

  Blue and red light
• What is the absorption spectrum of chlorophyll-a?

  Blue and red
• What is the action spectrum in photosynthesis?

  Range of light for possible photosynthesis
• What do accessory pigments do?

  They assist chlorophyll-a in absorbing light
• How do accessory pigments protect plants?

  By absorbing harmful wavelengths
• What is the function of bacterial chlorophyll?


  Specialized chlorophyll-a in bacteria
• What are the two main processes in photosynthesis?

  • Light-dependent reactions (LDR)
  • Light-independent reactions (LIR)
• Where does photosynthesis occur in plants?

  In the leaves, specifically mesophyll cells
• What is the structure of chloroplasts?

  Football-shaped, double membrane with stroma
• Where do light-dependent reactions occur?

  In the thylakoid membrane
• Where do light-independent reactions occur?

  In the stroma
• What are the products of light-dependent reactions?

  Oxygen, ATP, and NADPH
• What is the product of light-independent reactions?

  Glucose
• What limits the production of glucose in light-independent reactions?

  ATP and NADPH availability
• What are the reactants of light reactions?

  Water
• What happens during photolysis?

  Water is split into oxygen and hydrogen
• What is the byproduct of the light-dependent reaction?

  Oxygen
• What is substrate-level phosphorylation?

  ADP + Pi → ATP
• What is the sequence of events in light-dependent reactions?

  1. Absorption of light by PS2 and PS1
  2. Excitation of electrons
  3. Electron transport through couriers
  4. Formation of NADPH and ATP
• What do Photosystem II and Photosystem I absorb?

  Light at 680 nm and 700 nm
• What happens to an electron when it is excited?

  It moves to an electron courier
• What are the components of the electron transport chain (ETC)?

  • Complex I: NADH dehydrogenase
  • Complex II: Succinate dehydrogenase
  • Complex III: Cytochrome bc
  • Complex IV: Cytochrome c oxidase
• What happens to water in the lumen during light reactions?

  It splits due to light, producing oxygen