- Directly or indirectly, all of the energy in living systems needed for metabolism comes from the sun. - Photosynthesis is the process by which light energy is converted to chemical energy. - Autotrophs are organisms that use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds. - Most Autotrophs, including plants, are photosynthetic organisms. - Heterotrophs are organisms that get energy directly from food. Heterotrophs get this energy from the process of Cellular Respiration. - Cellular Respiration is a metabolic process similar to burning fuel. Cellular Respiration releases much of the energy in food to make ATP. - In cells, chemical energy is stored in food molecules that are released gradually in a series of enzyme-assisted chemical reactions. -ATP is a nucleotide with two extra energy-storing phosphate groups. ATP is needed to power chemical reactions in cells. Some chemical reactions only require little ATP. ~ How A Cell Releases Energy~ H2O + ATP → ADP + P + Energy
- Plants, Algae, and some bacteria capture about 1 percent of the energy of the sunlight the reaches Earth and convert it to chemical energy through Photosynthesis. ~The Stages Of Photosynthesis~
Step 1: Energy is captured from sunlight. Step 2: Light energy becomes chemical energy, which is stored in ATP and NADPH for a short time. Step 3: The chemical energy that was stored powers the formation of organic compounds, using carbon dioxide.
6CO2 + 6H20 C6H12O6 + 6O2
- Pigments are structures that contain light-absorbing substances. - Chlorophyll is the primary pigment involved in photosynthesis. (Absorbs Red and Blue; Reflects Green and Yellow) - Plants contain two types of chlorophyll: Chlorophyll a and Chlorophyll b. Both are important in photosynthesis - Carotenoids are pigments that produce yellow and orange fall leaf colors, as well as the colors of many plants. They also absorb wavelengths of light different from those absorbed by Chlorophyll. - Thylakoids are disk-shaped structures that contain clusters of pigments. - Electron Transport Chains are a series of molecules through which excited electrons are passed along a thylakoid membrane. - NADPH is an electron carrier that provides the high-energy electrons needed to make carbon-hydrogen bonds in the third stage of photosynthesis. - Carbon Dioxide Fixation is the transfer of carbon dioxide to organic compounds. - The Calvin Cycle is a series of enzyme-assisted chemical reactions that produces a three-carbon sugar. ~The Calvin Cycle~ Step 1: A CO2