1. Quaestio: How does photosynthesis support life on Earth?
Nunc Agenda:
List at least 3 ways you benefit from the capture and usage of the sun’s energy

2. Photosynthesis Overview
A process that captures energy from sunlight to make sugars that store chemical energy
The energy for almost all organisms begins as sunlight
Photo = light
Synthesis = make
Plants “make” usable
forms of energy from
“light” energy.

6. Photosynthesis Equation
sunlight
CO2 + H2O O2 + C6H12O6
Carbon Dioxide + Water + Light Energy  Oxygen + Glucose

7. Questions: What are the “raw” materials needed for photosynthesis?
What are the products?
Where does the energy for this process come from?

8. The Electromagnetic Spectrum
The Electromagnetic Spectrum: The entire range of frequencies or wavelengths of electromagnetic waves.
Can you think of different forms of electromagnetic radiation?

10. Visible Light
Visible light is all of the electromagnetic radiation that humans can detect with their own eyes.
All of the frequencies of visible light produce white light when combined (the light we see).
Visible light is only a small sliver of the electromagnetic spectrum.

14. Light Energy
All of the light energy on Earth comes from our closest star… the Sun

15. Another View

17. Light from the Sun Sustains Life on Earth

22. Light Energy, Cont’d
Light travels in waves but also acts as a particle when it strikes matter.
Photon: a particle of light with a fixed amount of energy.

23. How Light and Matter Interact
How do plants “capture” the energy from the sun?
Plants absorb the energy contained in photons.
The plant uses this absorbed energy to create chemical bond energy.

25. Pigments A substance the absorbs light
the pigment in plant cells is chlorophyll
When you “see” an object’s color, you are seeing the wavelengths of visible light that are reflected from it.

28. The pigment chlorophyll absorbs more light energy at certain wavelengths.

29. A leaf acts as a “sun net”
Plants convert the energy of the sun into chemical energy they can use.
A leaf acts as a “sun net”
Cover of “Nature”

30. Leaves and their cells are green because of chlorophyll.

31. Where does photosynthesis occur?
In the chloroplast of Plant cells.

32. The Plant Cell

33. Leaf cross section
Vein
Mesophyll
Stomata
CO2 O2
Chloroplast
Mesophyll cell
5 µm

34. Chloroplast Structure
Chloro- = green
-plast = body
Thylakoid
Photosynthetic membrane
Contains chlorophyll
Grana
Stacks of thylakoids
Stroma
Fluid inside the thylakoid

36. More Chloroplasts
Q:Where do you think the chlorophyll concentration is most dense?
A: Thylakoids

37. Elodea w/ Chloroplasts

39. *Key Idea*
The energy for life comes primarily from the Sun. Photosynthesis provides a vital connection between the Sun and the energy needs of living systems.
Heterotrophs rely on autotrophs.

41. Questions Where in the cell does photosynthesis take place?
Where does the energy needed for photosynthesis come from?
What substance is released as a waste product?
How do you think changing the amount of available CO2 will affect the rate of photosynthesis?

42. Regents Part C question
Photosynthesis is a vital process on Earth. Explain its importance to an organism by answering each bullet point.
Identify the organelle where this process occurs.
Identify 2 raw materials needed for this process.
Identify 1 energy-rich molecule that is produced.
State how organisms use the energy-rich molecule.
State how a gas produced by the process is recycled in nature.