5.1 Photosynthesis

• The overall equation for photosynthesis involves the reactants carbon dioxide and water, and produces glucose and oxygen
• Photosynthesis is the primary source of energy for most life on Earth.


  True
• What is photosynthesis?

  Process using sunlight
• Where in a plant cell does photosynthesis occur?

  Chloroplasts
• Match the chloroplast structure with its function:

  Thylakoids ↔️ Light-dependent reactions

  Grana ↔️ Stacks of thylakoids

  Stroma ↔️ Light-independent reactions
• What is the primary end product of the Calvin Cycle?

  Glucose
• PGA is reduced to G3P using ATP and NADPH
• What does CO₂ combine with during carbon fixation in the Calvin Cycle?

  RuBP
• Order the stages of the Calvin Cycle

  1️⃣ Carbon Fixation

  2️⃣ Reduction

  3️⃣ Regeneration
• What are the reactants of photosynthesis?

  CO₂, H₂O, sunlight
• What is the primary source of energy for most life on Earth?

  Photosynthesis
• Grana are stacks of lamellae within the chloroplast.

  False
• Photosystem II generates oxygen by oxidizing water.
• Order the process of ATP production in the light-dependent reactions:

  1️⃣ Sunlight is absorbed by PSII

  2️⃣ Electrons move through the electron transport chain

  3️⃣ Protons are pumped into the thylakoid lumen

  4️⃣ Chemiosmosis drives ATP synthase
• The light-independent reactions occur in the stroma of chloroplasts.


  True
• What is the final product of the Calvin Cycle?

  Glucose
• For every six molecules of CO₂, one molecule of glucose is produced in the Calvin Cycle.

  True
• Chlorophyll a absorbs light best at blue and red wavelengths.
• Extreme temperatures can denature the enzymes involved in the Calvin Cycle.
• Low levels of carbon dioxide prevent the enzyme RuBisCO from fixing enough CO₂, slowing down the Calvin cycle.
• What happens to enzymes in photosynthesis when temperatures become extreme?

  They denature
• Limiting factors of photosynthesis are environmental variables that restrict its rate when they are not at optimal levels.
• Sunlight provides the energy needed for the light-dependent reactions in photosynthesis.


  True
• Oxygen, a byproduct of photosynthesis, is essential for aerobic respiration.
• Photosynthetic organisms, such as plants and algae, form the base of most food chains and food webs.


  True
• Match the importance of photosynthesis with its explanation:

  Energy Source ↔️ Produces glucose for cellular respiration

  Oxygen Production ↔️ Releases oxygen for aerobic respiration

  Carbon Cycling ↔️ Removes CO₂ from the atmosphere

  Basis of Food Webs ↔️ Supports ecosystems with energy and nutrients
• What role does photosynthesis play in regulating the Earth's climate?

  Controls global carbon cycle
• The outer membrane of a chloroplast protects the organelle
• Steps in the light-dependent reactions

  1️⃣ Photosystem II absorbs sunlight

  2️⃣ Water is oxidized to release oxygen

  3️⃣ Electrons move through the electron transport chain

  4️⃣ Protons are pumped into the thylakoid lumen

  5️⃣ ATP synthase produces ATP
• ATP and NADPH generated in the light-dependent reactions are used in the light-independent reactions to convert carbon dioxide into glucose
• During the carbon fixation stage of the Calvin Cycle, CO₂ combines with RuBP to form PGA.


  True
• How many molecules of CO₂ must be fixed to produce one molecule of glucose?

  Six
• PGA is reduced to G3P using ATP and NADPH
• For every six molecules of CO₂, one molecule of glucose is produced in the Calvin Cycle.


  True
• One of the products of photosynthesis is oxygen
• Match the chloroplast structure with its function:

  Outer Membrane ↔️ Protects the chloroplast

  Inner Membrane ↔️ Controls transport

  Thylakoids ↔️ Light-dependent reactions

  Stroma ↔️ Light-independent reactions
• Where do the light-dependent reactions occur in the chloroplast?

  Thylakoid membranes
• What does Photosystem I reduce NADP+ to?

  NADPH
• What are the end products of the light-dependent reactions used in the Calvin Cycle?

  ATP and NADPH
• In the Calvin Cycle, carbon dioxide is fixed by the enzyme RuBisCO.