It is a well-known fact that everything in our life is closely connected with each other. All living creatures must take energy in order to survive and maintain their basic biological function. All of them do that in a different way. We eat, drink and breathe in order to live and stay healthy. It was proved by experts that the average adult inhales and exhales almost 7 or 8 liters of air per minute. The total amount of air that we use in a day comes out at 11,000 liters. Consequently, we use 550 liters of pure oxygen per day and convert it to carbon dioxide. So, if all people all over the world use that amount of oxygen in a day, why aren’t we running out of air? The only answer is photosynthesis.
Photosynthesis is a natural process of converting light energy from the sun into chemical energy, which is namely peculiar to plants. Photosynthesis is usually performed by many plants in order to get usable energy from nature. Plants use energy from the sunlight to convert water and carbon dioxide molecules into sugar molecule and oxygen, which all human use to breathe. The oxygen is released from leaves of the plant while the energy contained in glucose molecules and it is used in the plant for growth. During the process of making the glucose molecule, the plant gets the carbon and oxygen atoms it needs from carbon dioxide. It is obvious that the carbon dioxide doesn't include any hydrogen in it, and the plant needs another source for hydrogen. So it uses water.
We see that the plants produce oxygen only with the help of sunlight. So, what do they do at night? Like all living things plants need oxygen in order to produce energy from their food. That means that they respire. Respiration is also a natural process, which occurs when glucose combines with oxygen to produce cellular energy. Comparing to the photosynthesis, respiration takes place all the time. During this process, plants take in oxygen and give out carbon dioxide.
In conclusion, I would like to say that oxygen is the most important thing in our life that makes us to stay alive. Plants are the only living thing that provides human beings with that. That shows the importance of the plants in our life. However, we can say that not only plants play the most significant role in human life, but human also plays sizable role in their life. We must tend plants for stating them alive. If there were no plants to create oxygen, we would eventually run out of oxygen in the atmosphere. So, plants help us to keep the balance in the atmosphere. I can surely say that humans depend on plants to sustain our food chain. We eat salads from vegetables and fruits, which in its turn come from plants that photosynthesized to get energy. We also eat meat, which comes from cows and other animals that eat grass, which grows through photosynthesis. Thus, we can see that everything in our life depends on photosynthesis and how closely it impacts on our lives.
Reference
Altmann, T., Kossmann, J. (2001), Photosynthesis and primary metabolism. Trends Plant Sci. 6: 93-94
Bechtold U., Karpinski S., Mullineaux P.M., (2005), The influence of the light environment and photosynthesis on oxidative signalling responses in plant-biotrophic pathogen interactions. Plant Cell Environ. 28: 1046-1055
Cao B., Dang QL, Zhang S., (2007), Relationship between photosynthesis and leaf nitrogen concentration in ambient and elevated [CO2] in white birch seedlings. Tree Physiol. 27: 891-899
Donald R. Ort & Charles F. Yocum, Oxygenic Photosynthesis: The Light Reactions.
