What is photosynthesis?
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Q:

What is photosynthesis?

A:

Quick Answer

Photosynthesis is the process by which green plants manufacture their own food. The process takes place in small structures within the plant’s cells called chloroplasts. Photosynthesis evolved about 3 billion years ago, yet it remains the most important method for harvesting the sun’s energy on the planet.

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Full Answer

Most chloroplasts reside in cells located in a plant’s leaves, but they occasionally occur elsewhere as well. The chloroplasts use a substance called chlorophyll to absorb the energy carried by sunlight. Once this energy is absorbed, the chloroplasts combine it with carbon dioxide and water to produce sugars. The sugars allow the plants to store the energy for future use. Photosynthesis also produces oxygen, which is necessary for all animals to breathe.

Green plants that live in the world’s rivers, lakes and oceans engage in photosynthesis as well, but they must live relatively close to the surface. Many other simple organisms, such as algae and cyanobacteria, engage in photosynthesis. Nevertheless, scientists suspect that the process only evolved one time.

Scientists suspect that chloroplasts were initially independent organisms. Over millions of years, larger organisms engulfed them, and formed a symbiotic relationship with the small organelles. Chloroplasts have their own DNA, which most scientists interpret as evidence for the independent origin of the structures.

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Related Questions

  • Q:

    When does photosynthesis occur?

    A:

    Photosynthesis, the process by which plants convert the sun's energy to glucose, takes place during daylight hours when the plant's leaves are exposed to sunlight. This process only occurs in green plants and in some protist species. Carbon dioxide and water must also be present in order for photosynthesis to occur.

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  • Q:

    What is an explanation of photosynthesis for kids?

    A:

    Photosynthesis is the process that plants use to convert the energy in sunlight into food that they use for energy. In order to carry out photosynthesis, plants need not only sunlight but also water and carbon dioxide. The food they make is called glucose, which is a simple sugar.

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  • Q:

    Is photosynthesis endergonic or exergonic?

    A:

    Photosynthesis is an endergonic reaction. An endergonic reaction requires or absorbs energy from its surroundings, while an exergonic reaction releases energy. Most reactions that create or synthesize compounds are endergonic.

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  • Q:

    Why do we need photosynthesis?

    A:

    Photosynthesis is necessary because it forms the basis of the food chain. Photosynthesis, which occurs in green plants and algae, is the process by which sunlight combines with carbon dioxide, water and a chemical called chlorophyll to produce simple sugars. These sugars provide the plants with an energy source, and, when they are eaten by a predator, these sugars provide energy for the animal.

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