Notes on lesson on Genetics |



Genetic Materials

The material which gets transferred from parental generation to the offspring and which helps the offspring to express characteristics is called genetic material. DNA and RNA are the main genetic materials. Gene is a complex structure made up of more than one structure found in the DNA which performs more than one function.

DNA as The Heredity Material

The tape of information, known as DNA, encodes the messages for all the vital activities and transmits the genetic information from one generation to another. This concept that the DNA is a genetic material is supported by main two experiments given above.

Deoxyribonucleic Acid

Nucleic acids are the macromolecules of the almost biological important that form genetic material of all living organism, They are of two types:Deoxyribonucleic Acid (D.N.A) and Ribonucleic Acid(R.N.A). D.N.A is a macromolecule made up of helically twisted two anti-parallel strands.

Ribonucleic Acid

R.N.A is a type of nucleic acid to appear first on earth during the origin of life. It is formed by the polymerization of few to several hundred ribonucleotides. It is found in the nucleolus of nucleus, ribosomes, mitochondria, chloroplast and cytoplasm of eukaryotic cells and cytoplasm and ribosomes of prokaryotic cells. R.N.A is a single stranded non-helical nucleic acid.It helps in the synthesis of polypeptide chain or protein.On the basis of molecular size and functions, R.N.As are of three types: Ribosomal Ribonucleic Acid (rRNA), Messenger Ribonucleic Acid(mRNA). and Transfer Ribonucleic Acid(tRNA).

Replication of DNA

The formation of carbon copy or replica of D.N.A from parental D.N.A is called replication of D.N.A or duplication of D.N.A. In the semi-conservative mode of replication, two new DNA molecules are synthesized in which one strand is original and another strand and the other strand is newly assembled which occurs in the presence of various enzymes and steps.


Transcription is the process by which a single-stranded RNA is synthesized from DNA. The transcription process is similar to that of replication of DNA. It requires a promoter region and a terminator region and consists of various steps.


Translation is the complex process having various steps by which ribosomes convert the information carried by messenger RNA(mRNA) to the synthesis of proteins which requires various molecules.

Genetic Code

The linear sequence of nitrogen bases in a gene is a code for the sequence of amino acids in a protein. This relationship is called genetic code. In other words, the genetic code is defined as the dictionary that helps in translating the language of nucleic acid into the language of protein. The genetic code is of three types and has various characteristics.