1) Benefit of Photosynthesis
Describe two (2) ways that YOU benefit from the process of photosynthesis.
What happens when plants receive too much sun? Why?
How does the mapping of photosynthesis by NASA in space relate to climate change?
2) Fermentation
Fermentation and cellular respiration are BOTH used for energy-production in cells. As cellular beings, humans have the ability to perform both processes. Since energy production is markedly lower during fermentation, do you think it is a good idea for human cells to perform both processes? Why/why? EXPLAIN your response.
3) AUTOTROPHS & HETEROTROPHS
Autotrophs make their own food using energy they get directly from the environment, and carbon from inorganic sources such as CO2. By metabolic pathways of photosynthesis, plants and other autotrophs capture the energy of light and use it to build sugars from water and carbon dioxide. Heterotrophs get energy and carbon molecules from molecules that other organisms have already assembled.
Earth's early atmosphere held very little free oxygen, and chemoautotrophs were common. When the noncyclic pathway of photosynthesis evolved, oxygen released by photoautotrophs permanently changed the atmosphere, and it was a selective force that favored evolution of aerobic respiration. Photoautotrophs remove CO2 from the atmosphere; the metabolic activity of most organisms puts it back. Human activities disrupt this cycle by adding extra CO2 to the atmosphere. The resulting imbalance is contributing to global warming.
4) THE EVOLUTION OF PHOTOSYNTHESIS
Life theoretically originated on Earth 3.4 to 4 billion years ago. The atmosphere was thin: composed of methane, carbon dioxide, and water vapor. Any gaseous oxygen had been used up in the combustion (or oxidation) of materials when the Earth was very hot.
The cooling water collected in pools, assimilating nutrients from the rocks. As water evaporated, the nutrients concentrated, forming a rich soup. The first organisms would have lived well off this food source, breaking down the complex molecules into water and carbon dioxide through respiration. Eventually, as life grew, the need arose to somehow re-synthesize complex compounds, both to eat and to use for structure and function. Some organisms learned how to use the Sun's energy to synthesize large molecules from small molecules. Other organisms learned to use other sources of reductive power. These organisms that have learned how to build the building blocks of life are called autotrophs, or self-feeders. Autotrophs are found in the bacterial and plant.