The Basics of the Process of Photosynthesis
- 1. • Almost all plants are photosynthetic autotrophs, as are some bacteria and protists – Autotrophs generate their own organic matter through photosynthesis – Sunlight energy is transformed to energy stored in the form of chemical bonds (a) Mosses, ferns, and flowering plants (b) Kelp (c) Euglena (d) Cyanobacteria THE BASICS OF PHOTOSYNTHESIS
- 2. Light Energy Harvested by Plants & Other Photosynthetic Autotrophs 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
- 3. WHY WHY ARE ARE PLA PLANTS NTS GRE GREEN? EN? Plant Cells have Green Chloroplasts The thylakoid membrane of the chloroplast is impregnated with photosynthetic pigments (i.e., chlorophylls, carotenoids).
- 4. • Chloroplasts absorb light energy and convert it to chemical energy Light Reflected light Absorbed light Transmitted light Chloroplast THE COLOR OF LIGHT SEEN IS THE COLOR NOT ABSORBED
- 5. • Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water AN OVERVIEW OF PHOTOSYNTHESIS Carbon dioxide Water Glucose Oxygen gas PHOTOSYNTHESIS
- 6. • The Calvin cycle makes sugar from carbon dioxide – ATP generated by the light reactions provides the energy for sugar synthesis – The NADPH produced by the light reactions provides the electrons for the reduction of carbon dioxide to glucose Light Chloroplast Light reactions Calvin cycle NADP ADP + P • The light reactions convert solar energy to chemical energy – Produce ATP & NADPH AN OVERVIEW OF PHOTOSYNTHESIS
- 7. PHOTOSYNTHESIS • Sunlight provides ENERGY CO2 + H2O produces Glucose + Oxygen 6CO2 + 6H2O C6H12O6 + 6O2
- 8. Steps of Photosynthesis • Light hits reaction centers of chlorophyll, found in chloroplasts • Chlorophyll vibrates and causes water to break apart. • Oxygen is released into air • Hydrogen remains in chloroplast attached to NADPH • “THE LIGHT REACTION”
- 9. Steps of Photosynthesis • The DARK Reactions= Calvin Cycle • CO2 from atmosphere is joined to H from water molecules (NADPH) to form glucose • Glucose can be converted into other molecules with yummy flavors!
- 10. • In most plants, photosynthesis occurs primarily in the leaves, in the chloroplasts • A chloroplast contains: – stroma, a fluid – grana, stacks of thylakoids • The thylakoids contain chlorophyll – Chlorophyll is the green pigment that captures light for photosynthesis Photosynthesis occurs in chloroplasts
- 11. • The location and structure of chloroplasts LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast Mesophyll CHLOROPLAST Intermembrane space Outer membrane Inner membrane Thylakoid compartment Thylakoid Stroma Granum Stroma Grana
- 12. • Chloroplasts contain several pigments Chloroplast Pigments – Chlorophyll a – Chlorophyll b – Carotenoids – Xanthophyll Figure 7.7
- 13. Summary—Light Dependent Reactions a. Overall input light energy, H2 O. b. Overall output ATP, NADPH, O2 .
- 14. Summary—Light Independent Reactions a. Overall input CO2 , ATP, NADPH. b. Overall output glucose.
- 15. Review: Photosynthesis uses light energy to make food molecules Light Chloroplast Photosystem II Electron transport chains Photosystem I CALVIN CYCLE Stroma Electrons LIGHT REACTIONS CALVIN CYCLE Cellular respiration Cellulose Starch Other organic compounds • A summary of the chemical processes of photosynthesis