Chat with AIExam 1: The Science of Biology
Explain how a depletion in ozone might lead to a rise in the incidence of skin cancer.
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Answered by Examlex AI CopilotThe ozone layer, located in the Earth's stratosphere, serves as a protective shield that absorbs the majority of the sun's harmful ultraviolet (UV) radiation. Specifically, it filters out UVB rays, which are more energetic and damaging than UVA rays. A depletion in the ozone layer would result in more of these UVB rays reaching the Earth's surface.
UVB radiation is a significant risk factor for skin cancer because it has enough energy to damage the DNA in skin cells. When the DNA of skin cells is damaged, it can lead to mutations that cause the cells to grow uncontrollably, which is the hallmark of cancer. The three main types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma, with melanoma being the most dangerous.
The incidence of skin cancer rises with increased exposure to UVB rays for several reasons:
1. **Direct DNA Damage:** UVB rays can directly cause thymine bases in DNA to bond together, creating a dimer. These dimers can lead to errors in the DNA replication process, potentially causing mutations that can lead to cancer.
2. **Immune Suppression:** UVB exposure can suppress the local immune response in the skin. This suppression can prevent the body from recognizing and repairing damaged cells, which can then proliferate into cancerous cells.
3. **Oxidative Stress:** UV radiation can generate reactive oxygen species (ROS) in the skin, which can damage cells and their DNA, leading to mutations.
4. **Inflammatory Response:** Chronic sun exposure can lead to inflammation, which is associated with various stages of carcinogenesis.
As the ozone layer depletes, the protective filter becomes less effective, and more people are exposed to higher levels of UVB radiation. This increased exposure raises the risk of skin damage and, consequently, the incidence of skin cancer. This is why there is a strong emphasis on protecting the ozone layer through international agreements like the Montreal Protocol, as well as on personal protective measures such as using sunscreen, wearing protective clothing, and avoiding excessive sun exposure during peak UV radiation times.
The process of using and transforming energy is
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VerifiedC
The ozone-destroying contaminants in the upper atmosphere were found to be ________________________.
(37) Verifiedchlorofluorocarbons,or CFCs
Supernatural and ____________ hypotheses cannot be measured and tested and so are beyond the realm of scientific analyses.
(35) The theory that relates to the diversity of life is the theory of ___________________.
(33) Cells with a similar structure and function are organized into ____________ in the body.
(41) The process where organisms act to maintain a relatively stable internal environment is ___________.
(39) All the populations of a particular kind of organism are members of the same
(37) Why is it impossible for supernatural,religious,and unexplained phenomena to be explained by biology?
In a multicellular organism,different tissues that function together are grouped into
(39) All organisms on earth encode their genes in strands of _________.
(28) A biologist wants to test the effectiveness of a new food additive on causing growth in mice.An effective control group would be one that
(31) Which kingdom contains photosynthetic multicellular organisms that live on the land?
(45) Why is the study of biology central to the understanding and solving of the world's great environmental problems?
A discrete unit of genetic information is called a ___________.
(32) The different populations of all the species in a given area make up a(n)
(40) Which kingdom contains nonphotosynthetic multicellular organisms that digest their food internally?
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