3.5 Photosynthesis

• What is the primary purpose of photosynthesis?

  Convert light energy into chemical energy
• The output of carbon dioxide in photosynthesis is glucose
• Match the inputs of photosynthesis with their roles:

  Carbon dioxide (CO₂) ↔️ Provides carbon atoms for glucose

  Water (H₂O) ↔️ Provides hydrogen and oxygen atoms

  Light energy ↔️ Drives light-dependent reactions
• Light-dependent reactions take place in the stroma of chloroplasts.

  False
• Carbon dioxide provides the carbon atoms for glucose
• Where do light-dependent reactions occur in the chloroplast?

  Thylakoid membranes
• The Calvin cycle takes place in the stroma
• The light-dependent reactions occur in the thylakoid membranes of chloroplasts.
• Order the key inputs and outputs of the light-dependent reactions:

  1️⃣ Light energy

  2️⃣ Water

  3️⃣ Oxygen

  4️⃣ ATP

  5️⃣ NADPH
• Water provides hydrogen atoms and releases oxygen during photosynthesis.


  True
• Glucose is stored in plants as starch
• Order the key processes in the light-dependent reactions:

  1️⃣ Photosystems I and II absorb light energy

  2️⃣ Electron transport chain generates a proton gradient

  3️⃣ ATP synthesis
• Photosynthesis requires light energy and produces chemical energy in the form of glucose.
• In which part of the chloroplast does the Calvin cycle take place?

  Stroma
• The light-dependent reactions provide the energy carriers ATP and NADPH needed for the Calvin cycle.

  True
• The light-independent reactions use ATP and NADPH from the light-dependent reactions to fix carbon dioxide into glucose
• ATP and NADPH from the light-dependent reactions are used in the Calvin Cycle to convert carbon dioxide into glucose.


  True
• What are the outputs of the light-dependent reactions?

  Oxygen, ATP, NADPH
• The Calvin Cycle uses ATP and NADPH to fix carbon dioxide into glucose in the stroma of the chloroplast.


  True
• Carbon dioxide provides the carbon atoms needed to synthesize glucose
• Match the stage of photosynthesis with its location:

  Light-dependent reactions ↔️ Thylakoid membranes

  Light-independent reactions ↔️ Stroma
• What are the three phases of the Calvin Cycle?

  Carbon fixation, reduction, regeneration
• What is the definition of photosynthesis?

  Light energy to glucose
• Where does the Calvin Cycle take place in the chloroplast?

  Stroma
• The light-dependent reactions of photosynthesis take place in the thylakoid membranes.
• Steps involved in the light-dependent reactions

  1️⃣ Light absorption by photosystems I and II

  2️⃣ Electron transport chain generates proton gradient

  3️⃣ ATP and NADPH are produced

  4️⃣ Oxygen is released
• Which enzyme fixes CO₂ to RuBP in the Calvin Cycle?

  RuBisCO
• What is the role of glucose produced in photosynthesis?

  Energy for plant growth
• Photosystems I and II absorb light energy to power the electron transport chain.
• Light-dependent reactions occur in the stroma of chloroplasts.

  False
• In carbon fixation, CO₂ is fixed to RuBP by the enzyme RuBisCO.
• What is the main function of PS II in photosynthesis?

  Splits water; generates ATP
• The electron transport chain reduces NADP+ to NADPH, which is used in the Calvin Cycle.
• What is the main function of PS II?

  Splits water; generates ATP
• The key pigments in PS II include chlorophyll a, chlorophyll b, and carotenoids
• Photosynthesis is an anabolic process.


  True
• What is the chemical formula for glucose?

  $C_{6}H_{12}O_{6}$
• Order the stages of photosynthesis based on their location and function:

  1️⃣ Light-dependent reactions in thylakoid membranes

  2️⃣ Light-independent reactions (Calvin cycle) in stroma
• Which enzyme fixes carbon dioxide in the Calvin cycle?

  RuBisCO
• Light energy is required to produce ATP and NADPH in light-dependent reactions.


  True