Homework Unit 3 Life Science Magazine Project | страница 2

A mutation is any change in the original DNA of the organism. There are many different kinds of mutations, and here are a few types of mutations, Point mutation, frame-shift mutation, deletion, insertion, and inversion. Point mutation is a simple change in one base of the gene sequence (The boy saw the cat --> The boy haw the cat). Frame-shift mutataion is when one or more bases are inserted or deleted (The boy saw the cat --> The bos awt hec at). Deletion is when there is missing DNA (The boy saw the cat --> The saw the cat). Insertion is when there is the addition of extra DNA ( The boy saw the cat--> The boy kwh saw the cat). Inversion is when an entire section of DNA is reversed (The boy saw the cat --> The boy tac eht was). Any thing that causes mutations are called mutagens. Radiation, Ultraviolent light, certain types of food, chemicals, and smoking may cause mutations. There are two ways in which DNA can become mutated. One way is mutations being acquired. This happens when encironmental agents damages DNA, or when mistakes occur when a cell copies its DNA. Another way is mutations being inherited. If a parent has a mutation in their DNA, then the mutation is passed on to their children. Germline mutations causes diseases to run in families. If a child inherits a germline mutation from their parents, every cell in their body will have this mutation in their DNA. When mutations occurs in a gene, the wrong amino acid might be placed in the amino-acid chain. If this happens, there are three outcomes. One is the effect of a mutation causes no effect. Because some amino acids have more than one code, a mutation may not change the protein. Another one is the effect of a mutation is minor.

A mutated duck

with four legs

Mutations

This change is only a change in your appearance, so it is not very important. The other one is the effect of a mutation is great. This effect can be good, such as a plant having a resistance to disease. Or, this effect can be bad, such as a child having a genetic disorder or disease. Cells have different ways to repair mistakes in a DNA sequence. Certain enzymes in the cell corrects mismatched bese pairs, and other enzymes enable damaged DNA to be fixed.