1. Topic 2.9 – Photosynthesis Understandings
Photosynthesis is the production of carbon compounds in cells using light energy.
Visible light has a range of wavelengths with violet the shortest wavelength and red the longest.
Chlorophyll absorbs red and blue light most effectively and reflects green light more than other colours.
Oxygen is produced in photosynthesis from the photolysis of water.
Energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide.
Temperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate of photosynthesis.

2. Topic 2.8 – Photosynthesis Skills and Applications
Application: Changes to the Earth’s atmosphere, oceans and rock deposition due to photosynthesis.
Skill: Drawing an absorption spectrum for chlorophyll and an action spectrum for photosynthesis.
Skill: Design of experiments to investigate the effect of limiting factors on photosynthesis.
Skill: Separation of photosynthetic pigments by chromatograph (Prac. 4)

3. The process of photosynthesis converts light energy to chemical energy, which can be used by organisms for different metabolic processes
Most common form is glucose
How does the plant do it?

4. Green, why green?

5. Green, why green?
The energy factory of the plant cell is the chloroplast.
Plants contain a variety of pigments in these chloroplast but are mainly dominated by chlorophyll (green)
Plants use the same part of the electromagnetic spectrum as we do, we can process colors in this range, plants absorb energy between these wavelengths

6. Absorb that wavelength
In general, substances can do one of two things when they are struck by a particular wavelength (color) of light
Absorb that wavelength
Energy of the wavelength is absorbed and can be used
Reflect that wavelength
Energy of wavelength is not absorbed and you will see that reflected color

7. Why is this shirt red and white?

8. Why is this shirt red and white?
Sunlight is a mix of the wavelengths
of visible light.
When sunlight hits the red pigments in
the shirt, the blue and green are absorbed
but the red wavelength is reflected
When sunlight hits the white parts of the
shirt, all of the wavelengths are reflected
and we process this as white

9. How can we describe this?

10. Chlorophyll is green a green pigment, reflects green
Chlorophyll is green a green pigment, reflects green. When sunlight hits the chlorophyll red and blue are absorbed and used for photosynthesis.

11. Photosynthesis occurs in 2 stages
Light dependent
Light independent

12. Light Dependent Reactions

13. Light Dependent First stage, depends on light
Chlorophyll, and other pigments abosrd light and convert it to chemical energy, ATP
The light energy is also used for photolysis, the splitting of water into H and O
0 is released as waste
H and ATP are the useful products

14. Stage 2: Light Independent
The ATP and H from stage one (light independent) are used as energy to convert CO2 and H20 into useful molecules for the plant
Glucose FIXATION

15. FIXATION When inorganic elements are binded to form organic compounds
Requires energy to ‘FIX’ the products
Photosynthesis results in glucose but the energy produced in stage one LI reactions is used to ‘FIX’ many organic molecules for the plant

16. Photosynthesis versus cell respiration

17. Cell respiration runs at a fairly consistent rate in plants and is lower than that for mammals, why?

18. Rate of photosynthesis is not consistent, why
Rate of photosynthesis is not consistent, why? Why it it showing the plant taking in o2?

19. Measuring 02 is considered a direct measurement of photosynthesis, as long as a correction is made for cellular respiration

20. Environmental factors affecting rate of photosynthesis. 1
Environmental factors affecting rate of photosynthesis Increasing light intensity

21. Environmental factors affecting rate of photosynthesis. 2
Environmental factors affecting rate of photosynthesis. 2. Increasing temperature

22. Environmental factors affecting rate of photosynthesis. 3
Environmental factors affecting rate of photosynthesis. 3. Increasing C02

23. Class work/Home Work Photosynthesis lab, journal entries due by Monday
Page 111, question 6.

26. Energy Flow Through Ecosystems
Energy enters ecosystems mainly through photosynthesis
energy stored in the chemical bonds of sugar molecules
produce food using nonliving nutrients and sunlight
Autotrophs: have the ability to make their own organic molecules
PHOTOSYNTHESIS – uses light energy and inorganic molecules to produce organic molecules
CHEMOSYNTHESIS – uses inorganic molecules such as hydrogen sulfide to produce organic molecules (instead of sunlight)
Sugar is synthesized and used in plant tissues
plant tissues, growth
Energy is captured from sunlight
Carbon dioxide is absorbed from the air
Oxygen is released
Water is absorbed from soil, used in photosynthesis, and stored in cells
Inorganic mineral nutrients (nitrate, phosphate) are absorbed from soil and used in plant tissues
photosynthesis

27. Photosynthesis energy from CO2 sunlight O2 photosynthesis sugar H2O
plant tissues
other
nutrients
Fig. 28-1

28. Electromagnetic Spectrum

29. Light Independent Reactions
6CO H2O => C6H O2