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Cell Processes. Photosynthesis. Photosynthesis is the process by which a plant cell uses the energy of sunlight to make food In this process, photosynthesis uses light energy to combine carbon dioxide (CO 2 ) and water (H 2 O) to make glucose (C 6 H 12 O 6 ) Glucose is a simple sugar.
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Photosynthesis • Photosynthesis is the process by which a plant cell uses the energy of sunlight to make food • In this process, photosynthesis uses light energy to combine carbon dioxide (CO2) and water (H2O) to make glucose (C6H12O6) • Glucose is a simple sugar
Two Stages • How does photosynthesis take place in the cell? • Stage One: In the chloroplasts, chlorophyll traps the energy of sunlight • Chlorophyll makes plants green • Stage Two: The plant uses the energy to change carbon dioxideand waterinto glucose, the plant’s food
Photosynthesis • Plants absorb water through their roots • Carbon dioxide enters the plant through small openings in their leaves • The plant may use the sugar or store it in cell vacuoles • In addition to glucose, photosynthesis forms oxygen gas • This is released through openings in their leaves
Respiration • All organisms break down simple sugars to obtain energy • This process takes place in the mitochondria • Cellular respiration is the process by which cells break down sugar to release energy • Energy that is released is used to build, repair, and reproduce cells
Respiration • How does respiration take place in the cell? • Oxygen (O2) is combined with glucose (C6H12O6) to release energy • Carbon dioxide (CO2) is released as a waste product
Respiration • Animal cells get the oxygen from the air they breathe • The respiratory system take in oxygen and releases the CO2 and H2O formed during cellular respiration • Plants get the oxygen from photosynthesis • Animals get the glucose from the food they eat
Waste Elimination • Cells must get rid of waste products that could harm the organism • Wastes that collect in a cell are eliminated through the cell membrane by diffusion
Mitosis (add to Section 3) • Process by which cells reproduce • In mitosis, a cell divides to form two new cells • Serves three functions: • Many-celled organisms use for growth • Used to replace cells that die or are damaged • Single-celled organisms use for reproduction