PHOTOSYNTHESIS

EngageEssential QuestionExplain

Engage F List 10 things that you used today that depend upon photosynthesis. F Think hard and record your list on your hand-out. This is an individual activity.

Possible answers F Did you list items like the plants that you ate? F What about the clothing that you are wearing? F The bed or pillow that you slept on? F The fuel that heated your water, your stove, microwave, vehicle?

What about… Medicine Oil Coal

Essential Question What materials does a seed need… To develop into a tree?

Explore: van Helmont’s Willow experiment of 1648  I have learned from this experiment that all Vegetables do immediately, and materially proceed out of the Element of water only. For I took an Earthen vessel, in which I put 200 pounds of Earth that had been dried in a Furnace, which I moistened with Rainwater, and I implanted therein the Trunk or Stem of a Willow Tree, weighing five pounds; and at length, five years being finished, the Tree sprung from thence, did weigh 169 pounds, and about three ounces: But I moistened the Earthen Vessel with Rain-water and it was large, and implanted into the Earth, and least the dust that flew about should be co-mingled with the Earth, I covered the lip or mouth of the Vessel with an Iron-Plate covered with Tin, and easily passable with many holes. I computed not the weight of the leaves that fell off in the four Autumns. At length, I again dried the Earth of the Vessel, and there were found the same two hundred pounds, wanting about two ounces. Therefore 164 pounds of Wood, Barks, and Roots, arose out of water only.

Explain F Take into account van Helmont’s results and revisit your previous list of materials that you believed a seed needs to develop into wood. F Consider whether van Helmont’s conclusion that only water is needed to produce plant biomass is justified. If not, why not.

PHOTOSYNTHESIS F Photosynthesis is the ability of a plant to turn sunlight, air, and water into sugar (energy). F The overall reaction is: light chlorophyll CO 2 + H 2 O > C 6 H 12 O 6 + O 2 {Carbon dioxide} + {Water} yields {sugar} + {Oxygen} F Photosynthesis is vital to life for two reasons…

–1. The oxygen in the air comes from photosynthesis. The plants continue to replenish the oxygen in the air. –2. All of our food comes directly or indirectly from photosynthesis.

Where does Photosynthesis Occur? Sunlight Water Carbon Dioxide Oxygen Glucose #1 Light Dependent Reactions ATP NADPH ADP + P NADP + #2 Calvin Cycle Photosynthesis Steps ADP: Adenosine Di-Phosphate ATP: Adenosine Tri-Phosphate

Where are chloroplasts located? Chloroplast Stomata

Light is captured by pigments- molecules that absorb specific wavelengths of light. The main photosynthetic pigment is chlorophyll. Chlorophyll absorbs most wavelengths of light except green. Green is what is reflected which is why this pigment appears green.

Trapping Energy from Sunlight F Light-dependent Reactions – convert light energy into chemical energy (Electron Transport Chain) F Light-independent Reactions – the molecules of ATP produced in light- dependent reactions produce the simple sugars (Calvin Cycle)

F Intensity of light F Scarcity of water F Level of CO 2 What controls photosynthesis What controls photosynthesis?

Your Assignment F d=915 d=915 F It is the year 2040 and you are a research scientist. The amount of sunlight that reaches the earth has been reduced because of some major event like pollution, volcanoes or global fires. Farmers are asking you for help to save their failing crops. Figure out ways that you might help. F Complete the chloroplast assignment before the next class.