Photosynthesis

• Producers (autotrophs) are typically plants or algae that produce their own food using photosynthesis and form the first trophic level in a food chain
• Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar
• Photosynthesis occurs in plants and some algae
• Plants need light energy, CO2, and H2O to make sugar
• Photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis
• Biomass contains energy first derived from the sun: Plants absorb the sun’s energy through photosynthesis and convert carbon dioxide and water into nutrients (carbohydrates)
• Aerobic respiration needs oxygen, while anaerobic respiration does not
• Carbon dioxide and water are produced as waste products
• Most reactions of aerobic respiration happen inside mitochondria, tiny organelles inside the cytoplasm of the cell
• In every reaction, there are 2 types of energy: useful and wasted
• Wasted energy, such as thermal or heat energy, is produced as a byproduct of respiration reactions
• Most organisms cannot respire without oxygen, but some can continue to respire anaerobically if oxygen runs out
• Human muscle can respire anaerobically for short periods of time, even though it is relatively inefficient
• Some plants and fungi like yeast can respire anaerobically
• In yeast cells, glucose is converted to ethanol and carbon dioxide in anaerobic respiration