1. Photosynthesis Unit

2. Energy Flow through an Ecosystem

3. Photosynthesis
= a process that captures energy from sunlight to make sugars that store chemical energy

4. Photosynthesis (cont)
- plants absorb visible light for photosynthesis
- appears white but is made of a variety of colors (ROYGBIV) = visible spectrum

6. Photosynthesis (cont)
- pigment = a compound that absorbs light
- different colors absorb different colors of light

7. Photosynthesis (cont)
- chlorophyll = a molecule in chloroplasts that absorbs visible light
- two types: chlorophyll a (primary pigment)
chlorophyll b (accessory pigment)
- absorb mostly red and blue light
- neither a nor b absorbs green light (this is why plants appear green – color is reflected)

8. Structure of Chlorophyll a and Chlorophyll b

9. Photosynthesis (cont)
- carotenoids (accessory pigments) – contain yellow, orange, red, brown pigments
- in plants, chlorophylls are much more abundant than other pigments
- in fall, plants lose their chlorophylls (carotenoids then become visible)

15. 1) Chloroplast
2) Sunlight
3) Water (H20)
4) Thylakoid
contains: chlorophyll
5) Oxygen
6) Energy transferred to Dark Reactions
7) Carbon Dioxide (CO2)
8) Dark Reactions (Calvin Cycle)
9) Glucose (C6H12O6)

17. Light Reactions - capture energy in sunlight and transfer it
- take place in thylakoid membrane of a chloroplast
- chlorophyll absorbs energy from sunlight
- water is broken down (into H+ ions, electrons, and oxygen)

18. Light Reactions (cont)
- oxygen is released as a waste product
- NADPH is formed (functions like ATP = energy) when electrons are added to NADP+
- energy is transferred to make ATP (when H+ ions diffuse)
- overall, oxygen is given off as a waste product, NADPH and ATP are formed

19. Light Reactions

20. Light Reaction of Photosynthesis

21. Dark Reactions (Calvin Cycle)
- energy (NADPH and ATP) from light reactions make sugars
- occurs in stroma of chloroplast
- does not need sunlight

22. Dark Reactions (Calvin Cycle) (cont)
- carbon dioxide is needed
- a simple sugar, glucose, is formed from carbon dioxide and energy from ATP and NADPH

23. Dark Reactions (Calvin Cycle) (cont)
- overall, glucose, NADP+, and ADP are created.
NADP+ and ADP go back to the light dependent reactions

24. Dark Reactions (Calvin Cycle)

25. Dark Reactions (Calvin Cycle)

27. Equation of Photosynthesis

28. Functions of Photosynthesis
- ultimately produces food for all organisms

29. Energy Flow through an Ecosystem

30. Functions of Photosynthesis (cont)
- provides materials for plant growth/development
- simple sugars become starch and cellulose (found in cell walls)

31. Plant Growth/Development

32. Functions of Photosynthesis (cont)
- helps regulate Earth’s environment
- removes CO2 from atmosphere

33. Carbon Cycle

34. Factors that Affect Photosynthesis
1) Light Intensity – as light intensity increases, photosynthesis increases to a point

36. Factors that Affect Photosynthesis (cont)
2) CO2 Concentration – as CO2 concentration , photosynthesis increases to a point

38. Factors that Affect Photosynthesis (cont)
3) Temperature – as temperature increases, photosynthesis will increase to a point, then a decrease will occur if temperatures continue to increase