Subject: Biology

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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. Learn More

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. Learn More

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. Learn More

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). Learn More

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. Learn More


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. Learn More


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. Learn More

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. Learn More

Heredity And Variation

The process of transmission of characters from one generation to another is known as inheritance or heredity.The differences that are shown by the individuals of a species and also by the offsprings of same parents are referred as variations. Variations may be harmful, useless and useful. Harmful or useless variations make individuals unfit for the struggle for existence, whereas the useful variation is quite significant and make organisms fit in nature. Learn More

Mendel's Laws of Inheritance

The following principles of Inheritance were given by Mendel- Law of dominance, the law of segregation / purity of gametes, the principle of independent assortment. He formulated these by experimenting on pea plant. Learn More


The phenomenon of permanent association of genes of a single chromosome that can be inherited in successive generations in same position and proportion without any changes or separation is called linkage. Linkage is of two types: Complete and incomplete. Learn More

Crossing Over

Crossing over is a process of exchange of genetic materials or segments between non-sister chromatids of homologous chromosomes which take place in a various mechanism. Learn More


The sudden heritable change in amount or content and organization of genetic material of organism that results in the change in appearance is called mutation. They are of various types. Learn More


The organisms having more than two sets of chromosomes by the addition of another chromosome is called polyploidy. It may arise as a result of abnormal mitosis where chromosomes divide by cytoplasm fails to divide during cytokinesis. It is of various types. Learn More

Gene Expression

Gene expression or gene regulation is the ability of a gene of an organism to express phenotype at the molecular level. Biochemically, a gene is a segment of DNA with a specific sequence of nitrogenous base. It consists of the synthesis of RNA, polypeptide, structural proteins, enzymes, and hormones that control the structure and function (metabolic activities)of specific traits. Learn More

Gene Regulation

Various terms related to gene regulations are important and discussed above. The operon model is also important and discussed above. Learn More

Gene Expression In Eukaryotes

The genome of higher eukaryotes is very complex. The eukaryotic genome contains DNA many times as compared to the prokaryotic genome. There is various significance of gene regulation. Learn More

Interalleic Gene Interaction

Gene interaction is the influence of allelic or non-allelic genes on normal phenotypic expression of the trait. It is of types. Learn More

Intergenic Gene Interaction

The gene interaction in which the gene present in one gene locus interacts with the another gene present in another gene locus of the same or different chromosomes for the expression of phenotypic character is called intergenic or non-allelic gene interaction. Learn More

Lethal genes Or Pleiotropic genes

The phenomenon in which a single gene has multiple effects is called pleiotropy. This means a single gene often influences more than one phenotypic characters. The gene having multiple phenotypic effects because of its ability to control the expression of a number of characters is called pleiotropic genes. Learn More

Sex Linked Inheritance in Drosophila

The inheritance of characters linked to a particular sex is called sex-linked inheritance. Sex-linked inheritance is criss-cross patterns of inheritance. Criss-cross patterns of inheritance is a process of inheritance of traits from a parent to the grandchild [F2] of same-sex through the offspring [F1] of opposite sex i:e father passes his traits to his grandson through his daughter OR mother transfer traits to her granddaughters through her son. Learn More

Sex Linked Inheritance in Human Beings

In humans, about 120 sex-linked genetic disorders are found. These are classified as X-linked, Y-linked, and X-Y-linked trits. The common sex-linked disorders that are mostly found in humans are mostly recessive - Color-blindness and Haemophilia. Learn More

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