write the significance of light
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Answer:
1. Food: Photosynthesis is a concept in biology wherein food is synthesized by use of light. Light is the sole source of food generation for all living organisms on the earth. Except for a few chemotrophic bacteria? Almost all living beings depend on light for their food and energy.
Plants and other autotrophs synthesize their own food materials by use of light. The light which falls on the leaves and other greenish surfaces on plants are trapped. This trapped energy is converted to reserve energy in the form of food by a process known as photosynthesis. Here the light energy is used to synthesize carbohydrates. The autotrophs like plants use carbon-dioxide and water {CO2 +H2O= C6H12O6} to form carbohydrates in the presence of sunlight.
From these plants, animals get the required food materials and thereby needed energy for living.
These carbohydrates inside the body, break down and convert back into carbon dioxide and water releasing the energy from within after digestion.
So plants depend on sunlight for their food and animals depend on plants. Thus all the living beings are dependent on light for food.
This phenomenon is present both on the earth surface and also the marine environments.
3.Energy for bio-molecules synthesis: After food (carbohydrates) is consumed, it is broken down into energy. This energy is produced in the form of ATP (adenosine triphosphate). This ATP breaks down to ADP and AMP to release energy in cells and tissues.
This ATP is to build up the body proteins and maintenance of physiology. The cell and nucleus transcription mechanism uses this energy to form messenger RNA (m-RNA).
This m-RNA in the presence ATP again translates to produce desired hormones, enzymes, proteins and fats required for the body. Thus the light energy conserved in the food is used up to build and maintain the body.
3. For Vitamin D synthesis: Vitamin-D is a type of vitamin which is needed to be supplied from the external source. This is because it can be synthesized from ergosterol and cholesterol by irradiation with sunlight.
When the light fall on the skin, the ergosterol below the skin converts to vitamin-D. So if someone stays away from sunlight for long, he tends to develop the vitamin-D deficiency. Also to get a regular dose of vitamin D, it is important to expose to sunlight everyday. The best time would be in the mornings and evenings (before dawn).
4. Vision: All animals, birds are able to see the objects around them due to presence of eyes. But without light, these eyes might be of no use. Because of light, the eyes can receive the image of the objects and send the information to the brain. From this visual information we comprehend the objects. Hence we can notice that in darkness we could see nothing. So light makes us able to see objects around.
5. Colors: This whole world looks beautiful due to colors. But in darkness we see no colors. This is because all the colors in this world are possible only due to light. The light has many spectra. Each spectra has a color and these are broadly referred as VIBGYOR. In full form it is
Violet,
Indigo
Blue
Green
Yellow
Orange
Red
All these color have different wavelengths and frequency. And when light falls on an object, it absorbs some spectra and reflects others. The reflected light falls on to our eyeball and passes the impression to brain making it look colorful. So it is the ability of the object to absorb some spectra of light and reflect the remaining makes it look colorful. We would not be able to see the color if the light is absent or our eyes are not functional.
6. Maintenance of temperature: Light is a form of energy. And sunlight has huge energy by which the temperature on the earth is maintained. Due to this, the life exists on the earth.
7. Maintains Body clock or circadian rhythm: Everyday light keeps plants and animals ticking with time.
There is a clock inside both plants and animals which keep them active during the day and relaxed at night. This clock is controlled by light.
Plants broaden their leaves during daytime starting from sunrise till sunset. Even we can notice leaves and few flowers like sunflower which bent towards light through the day.
Explanation: