PHOTOSYNTHESIS Photosynthesis occurs in the chloroplasts of plant cells, algae and in the cell membrane of certain prokaryotes. light 6CO2 + 6H2O C6H12O6 + 6O2 glucose

pigments – structures containing light absorbing substances. chlorophyll – the primary pigment involved in photosynthesis; chlorophyll a and chlorophyll b carotenoids – a pigment that absorbs a different wavelength of light than chlorophyll; gives leaves their fall colors thylakoids – membranes of disk-shaped structures in the chloroplast that captures energy

Stage 1: Absorption of Light Pigment molecules in the thylakiods of chloroplast absorb light energy. Thylakoids

Stage 2: Conversion of Light Energy to Chemical Energy Electrons in the pigment are excited by light and move through an electron transport chain. Stage 3: Storage of Chemical Energy Carbon atoms from CO2 in the atmosphere are used to make organic compounds (sugars) in which chemical energy is stored.

Stage 1 Stage 2 Stage 3 electron transport chain

light-dependent reactions – Stage 1 (light reactions) Stage 2 light-independent reaction – Stage 3 (dark reactions)

Which metabolic process is shown at letter A? C6H12O6

Factors that affect Photosynthesis: 1. light intensity 2. CO2 concentration 3. temperature