81. Photosynthesis Uses Light Energy to Make Food Katrina Garibotto
Feb 23, 2016
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
Leaf Structure
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 mesophyll cells 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
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 thylakoids1. Chlorophyll molecules capture light energy.2. Energy used to separate H and O from water.3. O2 released – waste4. Hydrogen used to create NADPH.5. Energy used to create ATP.
Calvin Cycle Makes sugar using atoms from CO2 and
hydrogen and electrons from NADPH. Uses ATP created in light reactions Occurs in stroma (liquid)
Light Reactions and Calvin Cycle