Question

What is point mutation? Give one example.

Answer 1

Hint: A permanent change or unchangeable process occurring in a DNA sequence is known as mutation. Mutations can occur or arise due to DNA copying mistakes that have occurred during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. The changes occurred due to mutation can bring about several types of changes in the organism genes and genetics.

Complete answer:
A mutation is a permanent change in the nucleotide sequence of DNA, which may take place during replication or recombination of DNA. The changed or damaged DNA can be mutated by several processes such as by substitution, deletion, or insertion of base pairs.
A point mutation is a type of mutation that occurs in DNA or the genetic material of the cell. In this process, a single nucleotide base to be added, deleted, or changed altering the normal DNA composition. DNA consists of many nucleotides. There are five different types of molecules that compose the nitrogenous bases on nucleotides; they are cytosine, guanine, adenine, thymine, and uracil abbreviated in short C, G, A, T, and U. A point mutation occurs or takes place when only one nucleotide base is changed in some way. Although, in multiple point mutations, mutation can occur at multiple points in one strand of DNA.
In some cases, point mutations may arise spontaneously during the process of DNA replication. The rate of mutations may also increase when a cell is exposed to mutagens. Three types of point mutations can be observed and these are substitution, deletion, and insertion.
A substitution mutation takes place when one base pair is substituted for another. This mutation is further classified into three types; nonsense, missense, and silent mutation.
An insertion mutation takes place when an extra-base pair is added to a sequence of bases and a deletion mutation takes place when a base pair is deleted from a sequence. These two types of point mutations are grouped because both of them can affect the sequence of amino acids produced.
Sickle-cell anaemia is a disease caused as a result of point mutation and it is a recessive disorder caused by a single substitution in the gene that creates haemoglobin. When in individuals two copies of this mutation are present, it results in thin sickle-shaped blood cells which results in disorder relating to haemoglobin cannot carry oxygen properly.

Note: The point mutation is a type of mutation which is caused when one single nucleotide base is added, deleted, or changed. This mutation has three types and they are substitution, deletion, and insertion. Sickle-cell anaemia is a genetic disorder and is the example of a point mutation. It is a type of disorder noticed in oxygen carrying capacity of the blood by the pigment, haemoglobin.