PHOTOSYNTHESIS-1 9 SCIENCE BIOLOGY .pptx

Photosynthesis is a vital process that occurs in plants, algae, and some bacteria. It's the conversion of light energy into chemical energy, stored in glucose. During photosynthesis, organisms absorb sunlight, water, and carbon dioxide. The light energy is used to split water molecules, releasing oxygen as a byproduct. The hydrogen atoms from the split water combine with carbon dioxide to form glucose, which serves as the plant's primary energy source.

1. PHOTOSYNTHESIS

2. 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

3. Light Energy Harvested by Plants & Other Photosynthetic Autotrophs 6 CO 2 + 6 H 2 O + light energy → C 6 H 12 O 6 + 6 O 2

4. Different wavelengths of visible light are seen by the human eye as different colors. WHY ARE PLA NTS GRE EN? Gamma rays X-rays UV Infrared Micro- waves Radio waves Visible light Wavelength ( nm )

5. Electromagnetic Spectrum and Visible Light Gamma rays X-rays UV Infrared & Microwaves Radio waves Visible light Wavelength (nm)

6. Sunlight minus absorbed wavelengths or colors equals the apparent color of an object. The feathers of male cardinals are loaded with carotenoid pigments. These pigments absorb some wavelengths of light and reflect others. Reflected light

7. Why are plants green? Reflected light Transmitted light

8. WHY ARE PLA NTS GRE EN? Plant Cells have Green Chloroplasts The thylakoid membrane of the chloroplast is impregnated with photosynthetic pigments (i.e., chlorophylls, carotenoids).

9. 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

10. 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

11. 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

12. Chloroplasts: Sites of Photosynthesis Photosynthesis Occurs in chloroplasts, organelles in certain plants All green plant parts have chloroplasts and carry out photosynthesis The leaves have the most chloroplasts The green color comes from chlorophyll in the chloroplasts The pigments absorb light energy

13. 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

14. 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

15. Plants Autotrophs : self-producers. Location: 1. Leaves a. stoma b. mesophyll cells Mesophyll Cell Chloroplast Stoma

16. Stomata (stoma) Pores in a plant’s cuticle through which water and gases are exchanged between the plant and the atmosphere. Guard Cell Guard Cell Carbon Dioxide (CO 2 ) Oxygen (O 2 )

17. Mesophyll Cell Cell Wall Nucleus Chloroplast Central Vacuole

18. Chloroplast Organelle where photosynthesis takes place. Granum Thylakoid Stroma Outer Membrane Inner Membrane

19. Thylakoid Thylakoid Membrane Thylakoid Space Granum

20. Breakdown of Photosynthesis Two main parts (reactions). 1. Light Reaction or Light Dependent Reaction Produces energy from solar power (photons) in the form of ATP and NADPH .

21. Breakdown of Photosynthesis 2. Calvin Cycle or Light Independent Reaction or Carbon Fixation or C 3 Fixation Uses energy (ATP and NADPH) from light rxn to make sugar (glucose).

22. 1. Light Reaction (Electron Flow) Occurs in the Thylakoid membranes During the light reaction , there are two possible routes for electron flow . A. Cyclic Electron Flow B. Noncyclic Electron Flow

23. A. Cyclic Electron Flow Occurs in the thylakoid membrane . Uses Photosystem I only P700 reaction center- chlorophyll a Uses Electron Transport Chain (ETC) Generates ATP only ADP + ATP P

24. A. Cyclic Electron Flow P700 Primary Electron Acceptor e - e - e - e - ATP produced by ETC Photosystem I Accessory Pigments SUN Photons

25. B. Noncyclic Electron Flow Occurs in the thylakoid membrane Uses PS II and PS I P680 rxn center (PSII) - chlorophyll a P700 rxn center (PS I) - chlorophyll a Uses Electron Transport Chain (ETC) Generates O 2 , ATP and NADPH

26. B. Noncyclic Electron Flow P700 Photosystem I P680 Photosystem II Primary Electron Acceptor Primary Electron Acceptor ETC Enzyme Reaction H 2 O 1/2O 2 + 2H + ATP NADPH Photon 2e - 2e - 2e - 2e - 2e - SUN Photon