A Simple Blog: Oxygen
What is Oxygen??
Oxygen is element number 8 on the periodic table with an atomic symbol of an “O”. It is a gas at room temperature, but melts at -361.82 degrees Fahrenheit. It makes up around 21 percent of Earth’s atmosphere. As a gas, oxygen is clear. But as a liquid, it is pale blue. It is a nonmetal element, but is highly reactive.
Joseph Priestly
Carl Wilhelm Scheele
Who Discovered Oxygen?
Oxygen has been produced by several chemists prior to the discovery in 1774, but all failed to recognize it as a distinct element. Joseph Priestly and Carl Wilhelm both independently discovered oxygen, but Priestly tends to receive the most credit. They both produced oxygen by heating mercuric oxide (HgO). Scheele called his “fire air” and Priestly called his “dephlogisticated air”. The name oxygen was created by Antoine Lavoisier who incorrectly believed oxygen to be necessary to form all acids.
Photosynthesis: The Production of Oxygen
Photosynthesis is the process by which plants and some bacteria (protists) synthesize sugar molecules from carbon dioxide, water and sunlight. Photosynthesis can be divided into 2 stages: Light Dependent Reactions and Light Independent Reactions/ Dark Reactions.
Light Dependent Reactions
The light dependent process takes place in the grana (stacked membrane structure within chloroplasts). In this process the direct energy of light helps the plant to make molecules that carry energy for utilization in the dark phase of photosynthesis. The plants use light energy to generate the co-enzyme NADPH & ATP ( Nicotinamide adenine dinucleotide phosphate)- molecules that carry the energy. Chemical bonds in these compounds store the energy & they are used during the dark phase.
Light Independent Reactions (Calvin Cycle)
This process uses the energy produced by the light dependent reaction to make carbohydrates that the plants need. The plant uses NADPH & ATP to fix carbon dioxide. The process uses carbon from the atmosphere (atmospheric carbon dioxide) to produce carbohydrates. A product of this cycle is glucose. The end of the electron transportation chain that gives energy to the plants to form carbohydrates requires an electron acceptor. This electron acceptor will regenerate depleted ATP. Plants also absorb oxygen while they engage in photosynthesis. This is known as respiration. During respiration, oxygen becomes the final electron acceptor.