LO’s Explain why photosynthesis is so important to energy and material flow for life on earth

2. LO’s Explain why photosynthesis is so important to energy and material flow for life on earth Know why plants tend to be green in appearance Understand that photosynthesis is a two fold process composed of the light-dependent reactions (i.e., light reactions) and the light independent reactions

3. Basic questions?? • What do plants eat? • Why do plants need light? • Why do plants need water? • Why are plants green?

4. Photosynthesis • Process that captures energy from the sun • Energy stored in carbohydrates • Oxygen is byproduct

5. Photosynthesis • 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

6. AN OVERVIEW OF PHOTOSYNTHESIS • Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water Carbondioxide Water Glucose Oxygengas PHOTOSYNTHESIS

7. CO2 and water are waste products of cellular respiration Oxygen – used for cellular respiration

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

9. Sunlight • Electromagnetic energy (radiation) • Packets of energy (photons) • Range of wavelengths

10. Plant Pigments • Found in chloroplasts • Absorb some visible wavelengths

11. Plant Pigments • Carotenoids – absorb photons of green, blue & violet wavelengths • Chlorophylls – absorb photons of red & violet-blue wavelengths

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

13. Why are plants green? Reflected light Transmitted light

14. Energy needs of life All life needs a constant input of energy 1. Heterotrophs (Animals) Get energy from “eating others” Make energy through respiration • 2. Autotrophs “self-feeder” (Plants) • Produce their own energy • Convert energy of suclight -- chemical energy • Make energy and synthesise sugars through PHOTOSYNTESIS

15. Photosynthetic Autotrophs • Solar energy powers glucose synthesis • Uses • Carbon dioxide • Water • Captured energy • Produces • Glucose • Oxygen

17. Heterotrophs • Consume other organisms • Cannot produce their own food • Food ultimately comes from autotrophs

18. Photosynthesis – looks and sounds like a complex process • Two stages of Photosynthesis : • Light reaction ( with a solar energy captured and transformed into chemical energy • Calvin cycle – the chemical energy is used to make organic molecules

19. Chloroplast LEAF CROSS SECTION MESOPHYLL CELL • The location and structure of chloroplasts LEAF Mesophyll Intermembrane space CHLOROPLAST Outer membrane Granum Innermembrane Grana Stroma Thylakoidcompartment Stroma Thylakoid

20. Photosynthesis occurs in chloroplast

23. LIGHT ENERGY WATER • Light energy is used to split water molecules – known as ‘Photolysis’ –chemical is broken down by photons • ATP is produced during photolysis • ATP and H ions will be used to fix CO2 to make organic molecules • Photosynthesis relies on water and sunlight for its initial reaction

25. AN OVERVIEW OF PHOTOSYNTHESIS Light • The light reactions convert solar energy to chemical energy • Produce ATP & NADPH Chloroplast NADP ADP + P Calvin cycle • 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 reactions

26. Plants and animals need each other to survive.