1. 81. Photosynthesis Uses Light Energy to Make Food Katrina Garibotto

2. Objectives  Describe the structure of a chloroplast.  Identify the overall reactants and products of photosynthesis.

3. 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

4. Photosynthesis Location  plant  leaf  mesophyll (cells)  chloroplasts (organelles)  stroma (liquid)  thylakoids (disks inside chloroplasts, surrounded by stroma)

6. Leaf Structure

8.  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

9. The Structure of Chloroplasts  chloroplast : organelle inside cell of a plant  found in mesophyll cells  contain chemical chlorophyll (green)  If it’s green on a plant, it contains chlorophyll.

10. The Structure of Chloroplasts stroma (liquid) thylakoids (discs)

11. Overview of Photosynthesis  Plants use energy from the sun to break apart water (H 2 O) and recombine it with carbon dioxide (CO 2 ) to create sugar (C 6 H 12 O 6 ) for food.  Leftover oxygen (O 2 ) is released into the air.  Reactants (input): sunlight, CO 2, H 2 O  Products (output): C 6 H 12 O 6, O 2

12. Overview of Photosynthesis

13.  Light reactions yield O 2.  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.

14. Light Reactions  The light reactions convert solar energy to the chemical energy of ATP and NADPH.  occur in the thylakoids 1. Chlorophyll molecules capture light energy. 2. Energy used to separate H and O from water. 3. O 2 released – waste 4. Hydrogen used to create NADPH. 5. Energy used to create ATP.

15. Calvin Cycle  Makes sugar using atoms from CO 2 and hydrogen and electrons from NADPH.  Uses ATP created in light reactions  Occurs in stroma (liquid)

16. Light Reactions and Calvin Cycle