Photosynthesis and Gas Cycles Notes


  • Chlorophyll is a chemical in chloroplasts that can absorb or trap light energy.
  • Photosynthesis is the necessary life process that transforms light energy into chemical energy. It involves a series of chemical reactions in which the light energy is used to change raw materials (carbon dioxide CO2 and water H2O) into products (sugar C6H12O6 and oxygenO2). The energy is stored in the chemical bonds of the glucose (sugar) molecules.
  • Plants perform cellular respiration as well as photosynthesis.
  • Plants convert the sugars they produce into other raw materials that are used by plants and animals for growth, repair, and energy needs.
  • Energy is a basic need of all living things. Photosynthesizing organisms obtain their energy from the sun and are often called producers because of their ability to produce glucose (sugar).
  • Photosynthesizing organisms are the foundation of virtually all food webs.
  • Decomposers break down materials so that they can be recycled and reused.
  • Energy enters ecosystem through photosynthesis.This energy is passed when organisms eat other organisms.This is illustrated in a food web.
  • Energy pyramids show that as you go up the pyramid (up each trophic level) the amount of energy decreases.There are more organisms at the bottom of an energy pyramid then at the top.
  • Producers form the base of energy pyramids and there are more organisms and energy at the bottom level.There can be many trophic/feeding levels in a food pyramid.There are usually first through third level consumers.Primary is first and secondary is second.
  • The Water Cycle is the continuous movement of water.Transpiration is the loss of water through the stomata on leaves.Evaporation is when water molecules in a liquid become molecules of water in a gas state.Condensation is when water molecules in a gas state become dense and form into a liquid state.Precipitation is when clouds form from condensation.As the clouds become heavy they release water in the form of rain, snow, sleet or hail.
  • In the Carbon Cycle, producers use the carbon from carbon dioxide to undergo photosynthesis and produce glucose and oxygen.Consumers in turn use the glucose and oxygen and produce carbon dioxide.The cycle begins again.
  • In the Nitrogen Cycle, nitrogen moves from the air to the soil, into living things, and back into the air. Nitrogen is found in plants that organisms eat and in the air. Decomposers release nitrogen back into the soil.
  • Many important elements and cycles in an ecosystem are chains of events that continuously repeat.(Water cycle, carbon cycle, nitrogen cycle)