Photosynthesis

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Discovered by : Jan Ingenhousz
Discovered in year : 1779

Photosynthesis is the conversion of the energy from the sun in to a usable chemical energy. Only the green parts of the plants are photoautotrophic because they contain chlorophyll, a green substance found in chloroplasts. When it was discovered in 1906, chlorophyll was the first molecule from a living thing to be found that contained magnesium. The basic ingredients for the entire process of photosynthesis are carbon dioxide, water, chlorophyll and sunlight.

In Photosynthesis carbon dioxide, water and the energy from sunlight together form sugar and oxygen. The oxygen being let out into the air and the glucose kept in the leaves to be used by the “glucose producing organism” (in this case a plant) or to be used by other living organisms when that plant is eaten or is decomposed. Simply put, Photosynthesis is a process by which plants make food for themselves.

Here is the scientific equation of the actions that take place in photoautotrophs (living organisms which can perform the photosynthetic reactions): (in the presence of light and chlorophyll) 6CO2 + 6H2O ===> C6H12O6 + 6O2

Discovery of Photosynthesis

There are many researchers who are credited with the discovery of Photosynthesis. Some of the prominent one's are as follows -

Jan Baptista Van Helmont - Jan Baptista Van Helmont began the initial research of photosynthesis in the mid-1600s. Van Helmont proposed that water is necessary for the plant growth (1648). He concluded that the water helped carry the nutrients to the tree and then simply evaporated into the air.

Joseph Priestley - In the early 1770’s, a British man (who received the recognition of discovering oxygen) took the next big important step in the understanding of photosynthesis found that a piece from a mint plants could restore the air in a container with a burning candle, so that the candle could be used again. Accidentally, one day, Joseph Priestley placed the candle in a dark corner of his laboratory. Since the mint plant could not carry out photosynthesis, the candle’s flame extinguished. Unfortunately, Mr. Priestley never did really understand that great role which light played in his experiment.

Jan Ingenhousz - Several years later, in 1779, a Dutch physician, wanted to find out whether flowers really did help cure illnesses. After many different tests, he finally concluded that only the green parts of plants cleaned the air and only when placed in strong light. Flowers and other non-green parts of plants used up oxygen just like animals. In 1796, Ingenhousz suggested that this process of photosynthesis causes carbon dioxide to split into carbon and oxygen. Then the oxygen is released as a gas. Later, other scientists discovered that sugars contain carbon, hydrogen and oxygen atoms in a ratio of one carbon molecule per molecule of water (CH2O). This is where the word carbohydrate comes from, carbo- for “carbon” and hydrate for “water”. Carbohydrates are a family of chemical compounds including sugars and starches, which are made up of large numbers of sugar units linked together.

Nicholas Theodore de Saussure - In 1804, the Swiss scientist repeated Van Helmont’s experiment but carefully measured the amounts of carbon dioxide and water that were given to the plant. He showed that the carbon in the plants came from carbon dioxide and the hydrogen from water.

Julius Robert Mayer - Finally a German physicist, formalized the concept that energy was being transformed from light to produce new chemicals in growing plants. Mayer believed that a specialized chemical process (now known as oxidation) was the ultimate source of energy for a living organism.

Role of in the Improvement Of Human Life

• Better understanding of the Plant Kingdom and how they function which has resulted increase in production of crops

• Awareness of the Plants role in Oxygen production has helped a lot in preventing pollution

• Directly or indirectly, photosynthesis fills all of our food requirements and many of our needs for fiber and building materials. The energy stored in petroleum, natural gas and coal all came from the sun via photosynthesis, as does the energy in firewood, which is a major fuel in many parts of the world.

• Full understanding and control of the intricacies of the photosynthetic process, can be used to increase crop yields of food, fiber, wood, and fuel, and also to better use of land. The energy-harvesting secrets of plants can be adapted to man-made systems which provide new, efficient ways to collect and use solar energy.