2. Photosynthesis

3. Autotroph vs. Heterotroph Autotroph- organism that makes its own food – We call autotrophs Producers – Plants, algae Heterotroph- an organism that cannot make its own food – Obtain energy by eating other organisms – We call heterotrophs Consumers – Animals, most bacteria, fungi

4.  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

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 WaterGlucoseOxygen gas PHOTOSYNTHESIS Glucose = sugar or carbohydrate

6. Photosynthesis Photosynthesis occurs in all cells with chloroplasts (mainly plants) Step 1: photo- Light energy is harvested Step 2: -synthesis Sugar is made

7. WHAT’S WITH LIGHT???

8. THE SUN: MAIN SOURCE OF ENERGY FOR LIFE ON EARTH

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

10. Different wavelengths of visible light are seen by the human eye as different colors. WHY ARE PLANTS GREEN? Gamma rays X-raysUVInfrared Micro- waves Radio waves Visible light Wavelength (nm)

11. Why are plants green? Reflected light Transmitted light

12. 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

13. Chloroplasts absorb light energy and convert it to chemical energy Light Reflected light Absorbed light Transmitted light Chloroplast Apparent Color: THE COLOR OF LIGHT SEEN IS THE COLOR NOT ABSORBED

14. Question: Where does photosynthesis take place? 13

15. In the chloroplasts!!- specialized organelle found in photosynthetic eukaryotes where photosynthesis takes place. LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast Mesophyll CHLOROPLAST Intermembrane space Outer membrane Inner membrane Thylakoid compartment Thylakoid Stroma Granum StromaGrana

16. Chloroplasts are comprised of: – outer membrane and inner membrane (together form the chloroplast envelope) – stroma (a thick fluid) – thylakoids (called grana when in stacks) – The pigement chlorophyll is imbedded in the thylakoid membrane Notice that the Thylakoid stacks are connected together

17. Where Photosynthesis happens Pigment molecules called chlorophyll are on the surface of the thylakoid membrane – Chlorophyll gives plants their green color Chlorophyll molecules absorb and capture light energy from the sun – The chlorophyll then uses the energy to combine H, C, and O atoms into sugars and oxygen molecules – Nearly all of the Oxygen in our atmosphere has been produced by plants

18. In Summary… Photosynthesis Chloroplasts convert light energy into chemical energy 6 CO 2 + 6 H 2 O + light energy  C 6 H 12 O 6 + 6 O 2 Carbon Dioxide + Water + Light  Sugar + Oxygen

19. pigments in the chloroplast- not just chlorophyll Chlorophyll a: most common pigment in chloroplast (absorbs blue &red light and reflects green light thus giving the chloroplast a green color)(chloro = green phylla + leaf) Accessory pigments: additional pigments that absorb different wavelengths (carotene, chlorophyll b, & xanthophyll)

21. But it’s not that easy… Photosynthesis occurs in two different phases

22. The Light Phase This phase occurs in the thylakoid In this phase, light is captured by the chlorophyll molecules – The chlorophyll molecules use the energy from the light to make: ATP: made from ADP, high energy cellular molecule used to enable cell processes. – ATP is made by the enzyme: ATP Synthase NADP+: low energy molecule made into the high energy molecule NADPH Both of these molecules move on to the dark phase

23. ADP vs. ATP

24. “Waste” Products Water is split, and Oxygen created during the light phase – Oxygen is released, hydrogen molecules from the water used in dark phase – Remember, this is the Oxygen that you breathe

25. The complicated view… (not on test)

26. 1. light 2. H 2 O 3. CO 2 5. granum 6. light reaction 11. Calvin Cycle 7. NADP + 8.ADP+P_ 9.ATP 10.NADPH 13. O 2 14. sugar 4. stroma 12. thylakoid The simplified version (on test) LightLight Reactions

27. The Calvin Cycle Also known as the Light Independent or Carbon fixation phase – This set of reaction does not rely on light – Occurs in the stroma (fluid inside of chloroplast) – Uses the products of the light reactions, H, O and C to make sugar molecules

28. The calvin cycle uses the H from the H 2 0 and the C from the CO 2 It also utilizes the ATP and the NADPH from the Light Reactions With these components, sugars are made in the stroma

29. 1. light 2. H 2 O 3. CO 2 5. granum 6. light reaction 11. Calvin Cycle 7. NADP + 8.ADP+P_ 9.ATP 10.NADPH 13. O 2 14. Sugar 4. stroma 12. thylakoid The Calvin Cycle Calvin Cycle

30. What is the Purpose? Sugar is produced during this phase – Sugar can be used to synthesize more complex molecules like: Starch Fats/Lipids – Sugar can be used to make ATP during cell Respiration – It can be stored in the tissues of organisms

31. Bring In – light – CO 2 –H2O–H2O Let Out –O2–O2 Produce – sugars So what does a plant need? 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy  +++ roots shoot leaves

32. Factors Affecting Rate of Photosynthesis 1.Temperature: increases rate up to a certain point 2.Light Intensity: increases rate up to a certain point 3.CO2 level: Increases rate up to a certain point 4.Water: decrease water, decrease photosynthesis 5.Minerals; Ex. Magnesium, Nitrogen

33. Photosynthesis Summary Who? – Green plants, algae, autotrophs Materials: – CO2+Water+Light Energy Source: – Light+Sunlight Products: – Food+Oxygen Timing: – When light is present Location: – chloroplast