Photosynthesis

• What is photosynthesis?• Exactly why is photosynthesis so important?• Where does photosynthesis occur?• What raw materials are needed for the process of

photosynthesis?• What is the balanced chemical equation for

photosynthesis?• What else should we remember about

photosynthesis?

What is photosynthesis?

• Photosynthesis is a chemical reaction in which light energy is converted to chemical energy in glucose. It is the means by which the energy in sunlight becomes usable to living things. Living things can eat glucose, we can't eat sunlight.

Exactly why is photosynthesis so important?

• Two big reasons. One product of photosynthesis is glucose (sugar), which provides the basis for most food chains. The second product of photosynthesis is oxygen which comes in handy if your happen to be an aerobic organism that requires oxygen for survival.

Where does photosynthesis occur?

• This question can be answered on various levels. On the planetary level, most photosynthesis occurs in the oceans, because the oceans occupy the vast majority (70%) of the earth's surface. In terms of organisms, photosynthesis occurs in autotrophs that contain the green pigment chlorophyll. This would include the entire plant kingdom, "half" of the Protista (the algae), & "half" the Moneran Kingdom (the blue-green algae). On the multicellular level, photosynthesis occurs in the leaves of plants. We will take an up-close & personal look at these in a bit ... On the cellular level, the reactions for photosynthesis occur in organelles called chloroplasts (in eukaryotic cells). Blue-green algae (which are prokaryotic) carry-out the photosynthesis reactions in the cytoplasm.

What raw materials are needed for the process of photosynthesis?

• Chlorophyll must be present. (Chlorophyll absorbs solar energy). Sunlight is necessary. That's why we call it PHOTOsynthesis. And from the environment, photosynthetic organisms must get water & carbon dioxide.

What is the balanced chemical equation for photosynthesis?

What else should we remember about photosynthesis?

• Well, it's an important component of the Oxygen-Carbon Dioxide Cycle. Organisms that carry-out photosynthesis are like oxygen factories. At the same time they are removing CO2 from the atmosphere. Increasing levels of CO2 appear to go hand in hand with increasing global temperature ("Global Warming"). So damaging the ecosystems where photosynthesis occurs (i.e. the rainforests, the oceans) reduces the amount of oxygen being pumped into the air (that's a bad thing) & slows the rate at which carbon dioxide is removed from the atmosphere (which also appears to be a bad thing).