Photosynthesis Chapter 8

Photosynthesis  Reaction  6CO 2 + 6H light = C 6 H 12 O 6 + 6O 2  Photosynthesis uses energy from the sun to convert water and CO 2 into O 2 and high-energy sugars  Occurs in the chloroplasts

CHLOROPLAST CONTENTS  chloroplasts contain grana (stacked plates)  grana made of thylakoids (flat plates)  colorless substance between thylakoids is stroma  Chlorophyll  Pigment made by chloroplasts  Absorbs the sun’s energy

Where do the “ingredients” come from?  Water– roots  CO 2 – into stomata from air  Energy– from sun 6CO 2 + 6H light = C 6 H 12 O 6 + 6O 2

Chloroplast  In plant cells ONLY  Contains chlorophyll, which makes it green  Thylakoid, grana, stroma

Electromagnetic Spectrum

ABSORPTION SPECTRUM  RED/ORANGE, BLUE, VIOLET RESPONSIBLE FOR PHOTOSYNTHESIS  CHLOROPHYLL DOES NOT ABSORB GREEN= WHY PLANTS ARE GREEN  ONLY 1% OF SUNLIGHT IS USED IN PHOTOSYNTHESIS

Leaf Pigments  Leaves contain chlorophyll, carotenoid (yellow & orange), and anthocyanin (reds & purples) pigments.

Paper Chromatography  Observe the different pigments in a green leaf.

 Chromatography animation Chromatography animation Chromatography animation

PHOTOSYNTHESIS  3 main events of photosynthesis:  1) absorption of light energy  2) conversion of light energy into chemical energy  3) storage of chemical energy in sugars 6CO 2 + 6H light = C 6 H 12 O 6 + 6O 2

AN OVERVIEW

Photosynthesis  Light Reaction: Thylakoid  Dark Reaction (Calvin Cycle): Stroma

Photosystems  Clusters in thylakoids that contain chlorophyll

BIOCHEMISTRY OF PHOTOSYNTHESIS: LIGHT REACTION  Light Reaction- in thylakoid  1) Light absorbed by chlorophyll pigments in photosystem II… excites electrons… electrons move down electron transport chain to photosystem I  H 2 O helps this happen  Energy carriers- ATP & NADPH carry energy from light reaction to dark reaction  Oxygen is produced

REVIEW: LIGHT REACTIONS  Reactants: H 2 0, sunlight energy  Products: O 2, ATP, NADPH 6CO 2 + 6H light = C 6 H 12 O 6 + 6O 2

AN OVERVIEW

BIOCHEMISTRY OF PHOTOSYNTHESIS: DARK REACTION  Dark reaction (Calvin Cycle)- in stroma  ATP and NADPH can’t store all their energy for a long time, so uses them to make high- energy sugars  1) CO 2 molecules enter from atmosphere…  2) Energy from NADPH and ATP combine with carbon (from CO 2 ) and produce glucose

Review: Dark Reaction Reactants: CO 2, ATP, NADPH Products: Glucose

Photosynthesis Diagram  Worksheet Worksheet

Review: Photosynthesis  Using your text, your notes, etc…  Make a cartoon modeling the light and dark reactions of photosynthesis  This cartoon should include graphics as well as text  This should be for a student studying photosynthesis in 8 th grade.