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81. Photosynthesis Uses Light Energy to Make Food. Katrina Garibotto. Objectives. Describe the structure of a chloroplast. Identify the overall reactants and products of photosynthesis. Vocabulary. chloroplast : organelle where photosynthesis occurs
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81. Photosynthesis Uses Light Energy to Make Food Katrina Garibotto
Objectives • Describe the structure of a chloroplast. • Identify the overall reactants and products of photosynthesis.
Vocabulary • chloroplast: organelle where photosynthesis occurs • chlorophyll: chemical compound inside chloroplasts • mesophyll: cells containing chloroplasts • stroma: liquid inside a chloroplast • thylakoid: disk-like structure inside chloroplasts • light reactions: release oxygen • Calvin cycle: create sugar
Photosynthesis Location • plant • leaf • mesophyll (cells) • chloroplasts (organelles) • stroma (liquid) • thylakoids (disks inside chloroplasts, surrounded by stroma)
Leaf Structure • epidermis – skin (protection) • mesophyll – cells containing chloroplasts • veins – allow substances to move around a plant (xylem for water, phloem for sugar) • stomata (plural for stoma) – allow gases to enter and exit the leaf (like pores) • air space – allows gases to diffuse through leaf
The Structure of Chloroplasts • chloroplast: organelle inside cell of a plant • found in mesophyllcells • contain chemical chlorophyll (green) • If it’s green on a plant, it contains chlorophyll.
The Structure of Chloroplasts stroma (liquid) thylakoids (discs)
Overview of Photosynthesis • Plants use energy from the sun to break apart water (H2O) and recombine it with carbon dioxide (CO2) to create sugar (C6H12O6) for food. • Leftover oxygen (O2) is released into the air. • Reactants (input): sunlight, CO2, H2O • Products (output): C6H12O6, O2
Overview of Photosynthesis • Light reactions yield O2. • Calvin cycle yields sugar. • These two processes depend on each other. • Products of light reactions are reactants for Calvin cycle. • Products of Calvin cycle are reactants for light reactions.
Light Reactions • The light reactions convert solar energy to the chemical energy of ATP and NADPH. • occur in the thylakoids • Chlorophyll molecules capture light energy. • Energy used to separate H and O from water. • O2 released – waste • Hydrogen used to create NADPH. • Energy used to create ATP.
Calvin Cycle • Makes sugar using atoms from CO2and hydrogen and electrons from NADPH. • Uses ATP created in light reactions • Occurs in stroma (liquid)