PATHOLOGY

Detailed explanation-1: -Mutations result either from errors in DNA replication or from the damaging effects of mutagens, such as chemicals and radiation, which react with DNA and change the structures of individual nucleotides. All cells possess DNA-repair enzymes that attempt to minimize the number of mutations that occur (Section 14.2).

Detailed explanation-2: -Summary. Mutations are caused by environmental factors k nown as mutagens. Types of mutagens include radiation, chemicals, and infectious agents. Mutations may be spontaneous in nature.

Detailed explanation-3: -Mutations can occur during DNA replication if errors are made and not corrected in time. Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation.

Detailed explanation-4: -Errors during DNA replication are not the only reason why mutations arise in DNA. Mutations can also occur because of damage to DNA. Mutations can result from an exposure to a mutagen: chemicals, UV rays, x-rays, or some other environmental agent.

Detailed explanation-5: -Mutations can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection. Germline mutations (that occur in eggs and sperm) can be passed on to offspring, while somatic mutations (that occur in body cells) are not passed on.