Photosynthesis: Chloroplast

• Chloroplast - eukaryotic organelle that absorbs energy from sunlight that drives the synthesis of organic compounds from CO2 and H2O
• Mesophyll - Cells where chloroplasts are mainly found and is the tissue in the interior of the leaf
• Stomata - microscopic pores where CO2 and O2 are exchanged
• Stroma - dense fluid within the inner membrane of chloroplast
• Thylakoids - Third membrane system made up of sacs
• Chlorophyll - green pigment that gives leaves their color and found in thylakoid membrane
• What is the simplified equation for photosynthesis?

  6CO2 + 6H2O + light energy → C6H12O6 + 6O2
• In photosynthesis equation, what are reduced and oxidized?

  Reduced: CO2

  Oxidized: H2O
• Since electrons increase in potential energy as they move from water to sugar, the process is endergonic
• Light-dependent reactions - Light energy is converted to chemical energy
• Photolysis - The splitting of water into oxygen and hydrogen using light energy and also giving away a pair of electrons
• In light-dependent reactions, what is the acceptor at the end of the process which would then be reduced?

  NADP+
• Photophosphorylation would not be possible without what process?

  chemiosmosis
• In LDR, what are the stored forms of chemical energy with high potential?

  NADPH; ATP
• Where are the locations of light-dependent reactions and the Calvin cycle respectively in the chloroplast?

  Light-dependent reactions: thylakoid membrane Calvin cycle: stroma
• Wavelength - distance between crest of EM waves
• Visible light - 380nm to 740 nm can be detected as various colors by the human eye
• Photons - light behaves as though it consists of discrete particles that have a fixed quantity of energy
• Pigments - substances that absorb visible light
• What colors of light do chlorophyll absorb the best?

  Violet-blue; red
• Chlorophyll A - key light-capturing pigment that participates directly in the LDR
• What are two examples of accessory pigments in chloroplasts?

  Carotenoids; chlorophyll b
• What is the afterglow called when electrons fall back to ground state and photons are given off in pigments like chlorophyll?

  Fluorescence
• Photosystem - composed of a reaction-center complex surrounded by several light-harvesting complexes
• Reaction-center complex - organized associated of proteins holding a special pair of chlorophyll a molecules and a primary electron acceptor
• Light-harvesting complex - various pigment molecules bound to proteins
• Primary electron acceptor - accepting electrons from excited chlorophyll a molecules
• Which photosystem can absorb 680 nm of visible light?

  Photosystem II
• Which Photosystem can absorb 700 nm of visible light?

  Photosystem I
• Photorespiration - Peroxisomes and mitochondria within the plant cell rearrange and split the 2-carbon compound which is released as CO2
• Where does photorespiration occur greatest among C3, C4 and CAM plants?

  C3 plants
• In C3 plants, during a hot, dry day, what does rubisco add to the calvin cycle?

  Oxygen
• In C4 plants, where is photosynthesis completed?

  Bundle sheath cells
• For C4 plants to generate extra ATP for regeneration of PEP what electron flow is needed?

  Cyclic electron flow.
• What does CAM stand for in the alternative carbon fixation of CAM plants?

  Crassulacean Acid Metabolism