What can UV light do to living things?

Answer 1

The sun radiates energy in a wide range of wavelengths, most of which are invisible to human eyes. The shorter the wavelength, the more energetic the radiation, and the greater the potential for harm. Ultraviolet (UV) radiation that reaches the Earth's surface is in wavelengths between 290 and 400 nm (nanometers, or billionths of a meter). This is shorter than wavelengths of visible light, which are 400 to 700 nm.

UV radiation from the sun has always played important roles in our environment, and affects nearly all living organisms. Biological actions of many kinds have evolved to deal with it. Yet UV radiation at different wavelengths differs in its effects, and we have to live with the harmful effects as well as the helpful ones. Radiation at the longer UV wavelengths of 320-400 nm, called UV-A, plays a helpful and essential role in formation of Vitamin D by the skin, and plays a harmful role in that it causes sunburn on human skin and cataracts in our eyes. The incoming radiation at shorter wavelengths, 290-320 nm, falls within the UV-B part of the electromagnetic spectrum. (UV-B includes light with wavelengths down to 280 nm, but little to no radiation below 290 nm reaches the Earth's surface). UV-B causes damage at the molecular level to the fundamental building block of life- deoxyribonucleic acid (DNA).

DNA readily absorbs UV-B radiation, which commonly changes the shape of the molecule in one of several ways. The illustration below illustrates one such change in shape due to exposure to UV-B radiation. Changes in the DNA molecule often mean that protein-building enzymes cannot "read" the DNA code at that point on the molecule. As a result, distorted proteins can be made, or cells can die.

But living cells are "smart." Over millions of years of evolving in the presence of UV-B radiation, cells have developed the ability to repair DNA. A special enzyme arrives at the damage site, removes the damaged section of DNA, and replaces it with the proper components (based on information elsewhere on the DNA molecule). This makes DNA somewhat resilient to damage by UV-B.

In addition to their own resiliency, living things and the cells they are made of are protected from excessive amounts of UV radiation by a chemical called ozone. A layer of ozone in the upper atmosphere absorbs UV radiation and prevents most of it from reaching the Earth. Yet since the mid-1970s, human activities have been changing the chemistry of the atmosphere in a way that reduces the amount of ozone in the stratosphere (the layer of atmosphere ranging from about 11 to 50 km in altitude). This means that more ultraviolet radiation can pass through the atmosphere to the Earth's surface, particularly at the poles and nearby regions during certain times of the year.

Without the layer of ozone in the stratosphere to protect us from excessive amounts of UV-B radiation, life as we know it would not exist. Scientific concern over ozone depletion in the upper atmosphere has prompted extensive efforts to assess the potential damage to life on Earth due to increased levels of UV-B radiation. Some effects have been studied, but much remains to be learned.

Answer 2

UV or ultraviolet light is an ionizing form of eletro-magnetic energy at the short end (270-320nm) of the visible spectrum of light. UV light causes chemical changes to cellular structure in living cells causing damage to the DNA in pairs of thymine molecules, one of the "base links" in the DNA ladder structure. With enough damge to the DNA in the cell, it cannot carry out its proper function or reproduce and the cell dies. With enough damge to enough cells, the organism itself can die. The amount of UV light needed to damage the cell varies depending on the wavelength (short or long, also called UVC, UVB, and UVA) and the intensity. That being said, most animals require some UVA exposure to produce Vitamin D in their systems. UVC, the most harmful, from the sun is mostly filtered out by the ozone layer of our atmosphere.

Answer 3

It causes cell mutation, often cancer. Humans get skin cancer due to overexposure to UV radiation and try to prevent it with sun block.

Answer 4

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Answer 5

it has powerufl rays that the ozone cant pick up. they can cause skin cancer

Answer 6

UV radiations do harm to living organisms. UV actually depletes their population.

Answer 7

UV rays are high energy waves. They can cause various problems for life on earth.

Answer 8

The UV rays are high frequency waves coming from the sun. these have adverse effect of living things like sin cancer, eye cataract, alteration of DNA etc.