Write the balanced chemical equation for the process of photosynthesis.

A straightforward word condition that can be utilized to depict the procedure of photosynthesis isCarbon dioxide + water — > Glucose + Oxygen + water. A fair synthetic condition for the procedure can be composed as 6\\(CO_2\\) + 6\\(H_2O\\) — > \\(C_6H_{12}O_6\\) + \\(6O_2\\). Generally, photosynthesis utilizes light to convert Carbon dioxide into Glucose.

Explain the mechanism of photosynthesis.

Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be depicted in the following equation:\\(6CO_2+12H_2O\xrightarrow{chlorophyll+sunlight}C_6H_12O_6+6O_2+6H_2O\\)The process of Photosynthesis is composed of following step:(a) Absorption of light energy by chlorophyll.(b) Conversion of light energy into chemical energy(c) splitting of water molecules into hydrogen and oxygen.(d) Reduction of carbon dioxide to form carbohydrate These steps need not take place one after another immediately. For example; desert plants take up carbon dioxide at night to make an intermediate. During daytime. they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.

Explain why, plants have low energy needs as compared to animals.

Plants do not need to move from one place to another. Movements in a plant are usually at the cellular level and hence a far less amount of energy is required by plants. Animals, on the other hand, need to move from one place to another; in search of food. So, the energy need of animals is pretty higher than of plants.

Emerson's enhancement effect and Red drop have been instrumental in the discovery of:

The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 670 nm (red light) and 700 nm (far red light). When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates. Wavelengths beyond 700nm are apparently of insufficient energy to drive any part of photosynthesis. So a huge drop in efficiency has been noticed at 700nm. This phenomenon is called as Red drop effect. In other words there is a sharp decrease in quantum yield at wavelengths greater than 680nm. This decrease in quantum yield takes place in the red part of the spectrum. The number of oxygen molecules released per light quanta absorbed is called as quantum yield of photosynthesis. This effect was first of all noticed by Robert Emerson.

What did Engelmann observe from his prism experiments?

T.W Engelmann: He described the first action spectrum of photosynthesis. By using a prism he split sunlight into its spectral components (VIBGYOR) and then illuminated green algae Cladophora placed in a suspension of aerobic bacteria. The bacteria were used to detect the sites of O\\(_2\\) evolution.Observation:1. Bacteria accumulated mainly in the region of blue and red light of the split spectrum.2. It resembles roughly the absorption spectra of chlorophyll a and b.Hence, the correct answer is 'Bacteria are accumulated towards red and blue light'.

Distinguish between photosynthesis and respiration.

PhotosynthesisRespirationIt takes place only in the presence of sunlight.It continues throughout day and night, in sun and darkness.It occurs only in the green cells of the plant.It occurs in all the cells of an organism.It is an endothermic reaction as it absorbs sunlight.It is an exothermic reaction, as it gives out energy.It utilises carbon dioxide and water.It evolves carbon dioxide and water.It builds up complex compounds such as carbohydrates from simple inorganic compounds. So, it is an anabolic process.It breaks complex substances into simple substances. So, it is a catbolic process.It converts light energy into chemical energy.It releases potential or chemical energy which is used variously in the body.Carbon dioxide and water are raw materials for photosynthesis.Sugars and oxygen are raw materials for respiration.It produces ATP by harvesting light energy.It forms ATP from energy liberated during oxidation of food.Hydrogen of water is used in the synthesis of NADPH.Hydrogen of food is used in the formation of NADP, NADPH and \\(FADH_{2}\\).ATP and NADPH are used in the synthesis of organic compounds.ATP and reduced coenzymes are made available to cells for various metabolic activities.

Explain that sunlight is essential for photosynthesis.

Photosynthesis is a biochemical process by which green plants synthesize simple sugars. The most important factor for photosynthesis is light. The rate of photosynthesis depends on the quantity and quality of light. Procedure to prove light is essential for photosynthesis:1) Take the potted plant and keep it in a dark place for 2-3 days so that the leaves get destarched.2) Attach light proof black paper strips on both sides of the leaf with the help of paper clips.3) Place the plant in sunlight for 3-4 hours. 4) Pluck the selected covered leaf and remove the black paper covering it.5) Perform starch test by boiling leaf first in boiling water followed by boiling in alcohol over a water bath and then rinsing with cold water and again placing it in iodine solution. Observation: The leaf turns blue-black except in the covered region. As the covered region did not receive light, photosynthesis did not occur. Hence no starch was formed there. The uncovered region received light and starch was formed there due to photosynthesis.Result: Light is essential for photosynthesis.

Which one of the following options is true in photosynthesis?

Photosynthesis is the process in which autotrophs such as green plants use carbon dioxide and water in presence of sunlight to synthesize nutrients such carbohydrates in the form of glucose and release oxygen. In this carbon dioxide is reduced to glucose and water is oxidized to release oxygen. Hence the reaction is an oxidation-reduction reaction. Thus the correct answer is option B.

Correct equation for photosynthesis is

Photosynthesis is an anabolic process happening in green plants during which plant body synthesises its own food material by taking carbon dioxide from atmosphere and water from soil in presence of sunlight. In photosynthesis, carbon dioxide and water helps in the formation of glucose which is food for the plants and evolution of oxygen also takes place. In this process, six molecules of carbon dioxide and 12 molecules of water is used to form one molecule of glucose. Six molecules of oxygen gas is evolved which comes from the water and not from the carbon dioxide. Six molecules of water are also formed.So, following is the correct equation for photosynthesis:\\(\displaystyle 6CO_2 + 12H_2O\overset {Light} {\underset {Chlorophyll}{\longrightarrow} } C_6H_{12}O_6+ 6O_2+6H_2O\\)

During photosynthesis, the oxygen in glucose is from

Photosynthesis is the process of carbon fixation which mainly takes place in two steps, light reaction, and dark reaction. ATP and NADPH\\(_2\\) are produced in the light reaction which is utilized for carbon fixation during the dark reaction. When the plant makes the glucose molecule, it gets the carbon and oxygen atoms it needs from carbon dioxide, which is taken from the air through the stomatal openings and hydrogen from water molecules.Oxygen from water molecule is released in the form O\\(_2\\) during light reaction.So, the correct answer is option B.

Early Experiments of Photosynthesis | Definition, Examples, Diagrams

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Introduction to the history of photosynthesis

There are the scientists who explained the life-sustaining process, photosynthesis.

Aristotle: Over two thousand years ago, he said that plant absorbs all the inorganic and organic material directly from the soil.
Jan Baptista Von Helmont: In the year 1648, he conducted an experiment. In this experiment, He grew a weighed mass of willow tree in a pot with the weighed amount of soil. He covered the soil with the lid with small the small hole. The lid allows only rainwater to pass. After five years, he discovered that the mass of the tree and soil more than it did at the start. He concluded that major substance for plant growth is water.
Stephan Hales: He described that plant exchanges gases with the surroundings.
Priestley: He demonstrates that plant has the ability to reserve air.
Igenhouz: He discovered that plants has the ability use carbon dioxide only in the presence of sunlight.

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Recall the history of photosynthesis

Many scientists have contributed to understanding how plants carry out photosynthesis. These are as follows:
1. Van Helmont (1648) concluded that all food of the plant is derived from water and not from the soil.
2. Stephen Hales (Father of Plant Physiology) (1727) reported that plants obtain a part of their nutrition from air and light may also play a role in this process.
3. Joseph Priestley (1772) demonstrated that green plants purify the foul air (i.e., Phlogiston), produced by burning of the candle, and convert it into the pure air (i.e., Dephlogiston).
4. Jan Ingen-Housz (1779) concluded by his experiment that purification of air was done by green parts of the plant only and that too in the presence of sunlight. Green leaves and stalks liberate dephlogisticated air during sunlight and phlogisticated air during dark.
5. Jean Senebier (1782) proved that plants absorb CO

_{2}

and release O

_{2}

in presence of light. He also showed that the rate of O

_{2}

evolution depends upon the rate of CO

_{2}

consumption.
6. Lavoisier (1783) identified the pure air (i.e., phlogiston) as oxygen (O

_{2}

) and noxious air (i.e., Phlogiston) produced by the burning of the candle as carbon dioxide (CO

_{2}

).
7. Nicolas de Saussure (1804) showed the importance of water in the process of photosynthesis. He further showed that the amount of CO

_{2}

absorbed is equal to the amount of O

_{2}

released.
8. Pelletier and Caventou (1818) discovered chlorophyll. It could be separated from the leaf by boiling in alcohol.
9. Sachs (1864) discovered the carbohydrate as a product of the photosynthesis.
10. Emerson and Arnold (1932) described the occurrence of light and dark reaction during the process of photosynthesis.
11. Robert Hill (1937) demonstrated the photolysis of water in light reaction of photosynthesis.

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Introduction to the history of photosynthesis

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Recall the history of photosynthesis

REVISE WITH CONCEPTS

Photosynthesis

Write the balanced chemical equation for the process of photosynthesis.

Explain the mechanism of photosynthesis.

Explain why, plants have low energy needs as compared to animals.

Emerson's enhancement effect and Red drop have been instrumental in the discovery of:

What did Engelmann observe from his prism experiments?

Distinguish between photosynthesis and respiration.

Explain that sunlight is essential for photosynthesis.

Which one of the following options is true in photosynthesis?

Correct equation for photosynthesis is

During photosynthesis, the oxygen in glucose is from