Question

Does glucose actually react with oxygen during cellular respiration?

Answer 1

Hint :All cells need the energy to carry out their functions. This energy is secured by performing a sequence of chemical reactions that are together called respiration. Cellular respiration can occur aerobically and anaerobically depending on the presence of oxygen. Glycolysis in cellular respiration is the common first step of conversion of glucose in both aerobic and anaerobic respiration.

Complete Step By Step Answer:
Cellular respiration is when oxidation of glucose takes place. Glucose is an important respiratory substrate. Glucose can only react with oxygen during aerobic respiration. When there is oxygen present, glucose performs glycolysis resulting in energy and certain by-products. The main aim of glycolysis is to produce energy in the form of ATP.
During aerobic respiration, glucose is broken down. These products break down and then combine with oxygen from water and carbon-di-oxide. Among the three substances produced, water is used by the cells, energy is utilized for chemical activities and carbon-di-oxide is the waste product that is expelled out.
Let us now see the reaction of Glycolysis of cellular respiration:
 $ {{C}_{6}}{{H}_{12}}{{O}_{6}}~+\text{ }6{{O}_{2}}~\to \text{ }6C{{O}_{2}}~+\text{ }6{{H}_{2}}O\text{ + ATP(energy)} $
Cellular respiration has three steps: Glycolysis, Krebs cycle, and Oxidative phosphorylation. But the above reaction summarises all the processes.
The first step of respiration i.e. Glycolysis occurs in the cytoplasm of both plant and animal cells. But the remaining steps where ATP production is high occur in the mitochondria.
Therefore, Glucose does react with oxygen during cellular respiration.

Note :
During cellular respiration, an aerobic reaction can turn anaerobic if there is no oxygen. If after glycolysis the oxygen is absent the cell enters the process of fermentation rather than performing the Krebs cycle. The presence of oxygen is an important aspect of the mechanism of respiration. Also, do not confuse breathing with respiration. These are two different processes.