Chapter 7 Photosynthesis CO 7 Chapter 7 Photosynthesis CO 7 Name a plant you have seen recently.

Photosynthetic Organisms 1. *Organic molecules are built by photosynthesis. 2. Plants use the raw materials: carbon dioxide and water. 3. Chloroplasts carry out photosynthesis. *What is an organic molecule? Figure 7.1a

Brainstorm... What are some careers or college majors related to plants? U of I - College of Agriculture

Structure of a Leaf Make up the vessels in the plant to transport water and food Openings in the leaf allow for the exchange of gasses. Guard cells open and close these openings.

The Structure of Chloroplasts Figure 7.1b

Figure 7.2 Figure 7.2

Photosynthetic Pigments - Pigments found in chlorophyll absorb various portions of visible light; absorption spectrum. 1. Two major photosynthetic pigments are chlorophyll a and chlorophyll b. 2. Both chlorophylls absorb violet, blue, and red wavelengths best. 3.  Most green is reflected back; this is why leaves appear green.

Carotenoids are yellow-orange pigments which absorb light in violet, blue, and green regions. 4. When chlorophyll breaks down in fall, the yellow-orange pigments in leaves are visible. Figure 7.3a

Absorption Spectrum - spectrophotometer measures the amount of light that passes through a sample of pigments (like crushed green leaves) Figure 7.3a

Action Spectrum - measures the rate of photosynthesis at different wavelengths of light; measured by the rate oxygen is produced

Figure 7.3b

In one sentence summarize what this graph says about wavelengths, color of light, absorption and photosynthesis.

Checkpoint 1. What is the relationship between the absorption spectrum and the action spectrum? 2. How can we measure the rate of photosynthesis? 3. How is the wavelength of light related to the rate of photosynthesis? 4. A radish plant is grown using lights of different colors. Explain the chart.

6CO2 + 6H2O ------> C6H12O6 + 6O2 Photosynthetic Reaction 6CO2 + 6H2O ------> C6H12O6 + 6O2 Pg 119a

Two Sets of Reactions in Photosynthesis 1 Two Sets of Reactions in Photosynthesis 1. Light reactions cannot take place unless light is present. They are the energy-capturing reactions. a. Water is split b. ATP and NADPH are produced to power the Calvin Cycle c. Oxygen is released Pg 119b

2. Calvin Cycle Reactions a. These reactions take place in the stroma; can occur in either the light or the dark. b. These are synthesis reactions that use NADPH and ATP to reduce CO2. -- and make a carbohydrate, sugar Figure 7.4

The Light Reactions occurs in two systems: Photosystem I and II - the creation of ATP is a complicated process You will take a closer look at Photosystem I and Photosystem II in the Photosystem Coloring Worksheet

Are you still confused?    This is pretty hard to visualize, but through the magic of technology, we can watch these processes as animations McGraw Hill Animation

Summarize: 1. What is the purpose of the Calvin Cycle? 2. Where does the cell get its energy to perform these reactions? 3. What is the final product? 4. Why is carbon dioxide necessary?

Figure 7.6

Fortunately.... Summary Statements: AP Biology no longer requires the memorization of every step of the Calvin Cycle, but you should understand the beginning and the end and what it's purpose is.   Summary Statements:    What is the purpose of the Calvin Cycle?   Where does the cell get its energy to perform these reactions? What is the final product?  Why is carbon dioxide necessary?

What Factors the Affect Photosynthesis?   1. Light Quality (color) 2. Light intensity 3. Light Period 4. Carbon Dioxide Availability 5. Water Availability *Design an experiment to test ONE of the above factors* Rate of Photosynthesis can be measured by the amount of oxygen released or the amount of CO2 absorbed. Photosynthesis Simulation Waterweed Simulator

Quick Practice

Quick Practice grana thylakoid stroma O2

Pg 129b Light & H2O CO2 ADP NADP ATP Pg 129b NADPH O2 glucose

AB = ATP AC = phospholipids AD = light (energy) A = photosystem II B = photosystem I C = H20 D = Electron Transport Chain E = ATP Synthase AB = ATP AC = phospholipids AD = light (energy)

Photosynthesis Activities 1. Elodea photosynthesis rate (lab) 2.   Photosynthesis alphabet book 3. Chromatography of a spinach leaf 4. Viewing elodea cells chloroplasts 5. Fall colors observation