Photosynthesis

1. Photosynthesis Chapter 2, Lesson 1 Cell Processes and Energy

2. Sources of Energy • Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis. • Plants manufacture their own food through the process of photosynthesis. • An organism that makes its own food is called an autotroph • An organism that cannot make its own food, including animals such as a zebra and lion, is called a heteroptroph.

3. The process by which a cell captures energy in sunlight and uses it to make food is called photosynthesis. • The term photosynthesis comes from the Greek word photo which means “light” and synthesis which means “putting together.” • During photosynthesis, plants and some other organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugar.

4. The two Stages of Photosynthesis • Stage 1 – Capture the Sun’s Energy • In plants, this energy-capturing process occurs mostly in the leaves. • The green color comes from pigments, colored chemical compounds that absorb light. • The main photosynthetic pigment in cholorplasts is chlorphyll.

5. Stage 2 – Using Energy to Make Food • The cell uses the captured energy to produce sugars. • The cell needs to raw materials for this stage: water and carbon dioxide. • In plants, the roots absorb water from the soil and than the water moves up through the plant’s stem to the leaves. • Carbon dioxide enters the plant through small opening on the undersides of the leaves called stomata. Once in the leaves, the water and carbon dioxide moves into the chloroplast.

6. The Photosynthesis Equation • 6 CO2 + 6 H20  C6 H12 06 + 6 02 Carbon Dioxide + Water  A sugar + oxygen Click the link below to view a video on photosynthesis http://www.youtube.com/watch?v=1gLa5EWn9OI&feature=related