People and Plants
The symbiotic relationship between plants and people is made possible by the differences between cellular respiration and photosynthesis. While cellular respiration occurs in all living organisms, photosynthesis relies on chlorophyll and is unique to plants, algae, and some bacteria. Respiration and photosynthesis are essentially the same process in reverse. During photosynthesis CO2 and H2O are converted to glucose and oxygen, while cellular respiration uses glucose and oxygen which are converted to CO2 and H20.
Plants utilize molecules of chlorophyll which harness energy from the sun. That energy is used to break the bonds in water molecules producing hydrogen and expelling oxygen as a byproduct. Atmospheric C02 is absorbed by the plant through its pores, and is then combined with the hydrogen to create carbohydrates. The energy available in the form of carbohydrates is used by the plant, and any excess is further converted to starch for storage. Through the process of photosynthesis plants produce both the energy and oxygen necessary to sustain human life, as noted by Johnson (2010), “every oxygen atom in the air we breathe was once part of a water molecule, liberated by photosynthesis” (pg. 100).
Along with oxygen, people need food for fuel. Plants and people both utilize the adenosine triphosphate (ATP). Once ATP is generated in plants, it is further processed into sugars where the energy is used or stored. Humans generate ATP during the process of cellular respiration, where food energy from glucose is combined with oxygen. In essence plants make sugar out of ATP, while people make ATP out of sugar from plants or other animals that consumed plants. Without plants people could not harness energy from the sun.
While people may be dependent on plants the reverse may not be true. If a plant is placed in a sealed transparent container with the appropriate ratios of soil and water it may survive for extended periods of time. If the container is
Plants utilize molecules of chlorophyll which harness energy from the sun. That energy is used to break the bonds in water molecules producing hydrogen and expelling oxygen as a byproduct. Atmospheric C02 is absorbed by the plant through its pores, and is then combined with the hydrogen to create carbohydrates. The energy available in the form of carbohydrates is used by the plant, and any excess is further converted to starch for storage. Through the process of photosynthesis plants produce both the energy and oxygen necessary to sustain human life, as noted by Johnson (2010), “every oxygen atom in the air we breathe was once part of a water molecule, liberated by photosynthesis” (pg. 100).
Along with oxygen, people need food for fuel. Plants and people both utilize the adenosine triphosphate (ATP). Once ATP is generated in plants, it is further processed into sugars where the energy is used or stored. Humans generate ATP during the process of cellular respiration, where food energy from glucose is combined with oxygen. In essence plants make sugar out of ATP, while people make ATP out of sugar from plants or other animals that consumed plants. Without plants people could not harness energy from the sun.
While people may be dependent on plants the reverse may not be true. If a plant is placed in a sealed transparent container with the appropriate ratios of soil and water it may survive for extended periods of time. If the container is
References: Johnson, G. B. (2010). Essentials of the living world. (3 ed.). New York: McGraw-Hill. Wilks, D. (2013). Retrieved from http://www.dailymail.co.uk/sciencetech/article-2267504/The- sealed-bottle-garden-thriving-40-years-fresh-air-water.html