GENETICS

Genetics

Genetics

Structure of Genes, Chromosomes and DNA

The genetic information exists in DNA i.e. deoxyribonucleic acid in the cell of the body. There are four identical chemicals used in DNA which is called bases and thus abbreviated A, G, C and T. which are repeated in pairs over and over again (University of Leicester, nd., p.n.d.).

A distinct portion of the DNA of cell is gene. Genes act as a coded instruction in order to make everything that is needed by the body specially proteins. There are around 25,000 genes that exist inside human beings (University of Leicester, nd., p.n.d.).

In chromosomes, genes are wrapped up in bundles. There are 23 pairs of chromosomes that exist inside human body i.e. making total 46 chromosomes. Out of these pairs, there is a single pair which is known as sex chromosomes. The pair of sex chromosomes determines the gender of the human body i.e. human is male or female in addition to this it also tells some other characteristics of the body. The remaining pairs of chromosomes i.e. 22 remaining pairs are autosomal chromosomes which are used to determine the rest of the structure or makeup of the body (University of Leicester, nd., p.n.d.).

Mechanism and importance of DNA replication

In the reproduction of cells, DNA replication is significant and important. Since the reproduction of cells is very essential thus DNA replication has its great importance.DNA replication occurs through the mechanisms of meiosis and mitosis. In the DNA replication, there will be an additional DNA and the cell multiplies which allows the chance of reproducing “daughters” (Life science, 2011, p.n.d.).

Polymerization of deoxyribonucleotide units involve in the reaction of DNA replication in order to form macromolecular DNA. It is defined as follows:

Due to the damage of PPi, it is inserted as dNMP to 3'-OH of [dNMP]n. because of this process the course of synthesis is expressed to be from 5 inch to 3 inch. This course of synthesis is not bounded to DNA rather it is also applicable to the synthesis of RNA.

In the process of replication at the time when the original strands are not wounded. In order to form pairs, new nucleotides are inserted with the original strand's bases. The figure below illustrates the double helix model of DNA that was published by crick and Watson in the year 1953. This structure gives the possibility of replicating DNA by the use of template. In reality, in the process of DNA replication, each and every original strand is utilized as template that heps in synthesizing the new chain through pairing or combining G with C and T with A. after the completion of the process of replication, there will be 2 DNA double strands along with accurately the sequence of same base as that of original DNA with double strand. Semiconservative replication is another name for this kind of replication method. It consists of one strand of the ultimate double strand appears as the original strand which acts as a template i.e. parent strand and other is the ...