This video (from BOGObiology) provides a comparison between photosynthesis and cellular respiration. Watch the video before answering the questions below:
To watch this video on YouTube (and see closed captioning) - press the arrow icon in the bottom right corner of the video player.
The earth’s climate has changed many times over the course of its history (for example, in class we discussed the change from an anaerobic to an aerobic environment that took place about 2 billion years ago as a result of increased photosynthetic activity). Understanding current global climate change is an important area of scientific study. The amount of carbon dioxide, and other so-called “greenhouse gases”, is increasing in the atmosphere and thishas resulted in an increase in the mean global temperature. In an attempt to better understand the factors that play a role in global warming, scientists are attempting to learn more about both the natural and anthropogenic inputs and outputs of greenhouse gases.
Atmospheric carbon dioxide is constantly being fixed into sugars (and other macromolecules), which, in turn, are oxidized back into CO 2 . This relationship, on a global scale, is termed the carbon cycle. Through the burning of fossil fuels we are generating CO 2 at a faster rate than plants can fix them back into sugars and other carbon molecules.
Plants and other photosynthetic organisms play an important role in determining the amount of carbon dioxide in the atmosphere. They are both consumers and producers of carbon dioxide.