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Explore the concept of energy flow in living systems and the importance of autotrophs and heterotrophs coexisting in environments. Learn about photosynthesis, cellular respiration, and how energy is obtained from food.
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Energy & Living Systems Agricultural Biology
Almost all energy in living systems comes from the sun • Plants, algae, and certain bacteria absorb sunlight • Photosynthesis: The process of converting light energy (from the sun) to chemical energy (sugar)
Autotrophs vs. Heterotrophs • Autotrophs: Organisms that use energy from sunlight • Most are photosynthetic • Heterotrophs: Organisms that get their energy from food (rather than directly from sunlight) • Humans and other animals • Get energy from cellular respiration
Discussion With the person sitting next to you, come up with 3 examples of autotrophs and 3 examples of heterotrophs. Following this, discuss why you think it is important that heterotrophs and autotrophs exist together in environments.
Cellular Respiration • A metabolic process similar to burning fuel • This process releases much of the energy in food to make ATP • ATP: the main energy source of cells
How do we get energy from eating food? 1) Food is eaten. 2) Digestion begins. 3) Chemical energy is released gradually by enzyme-assisted reactions. 4) Some energy is released as heat. 5) The remaining energy is stored in ATP molecules. 6) ATP delivers energy within the cell (to power chemical reactions).