Salient Features of the Human Genome The human genome is made up of 3164.7 million nucleotide bases. On an average, a gene consists of 3000 bases, but size may vary. Human beings have about 30,000 genes. For over 50 percent of the discovered genes, the functions are still unclear. Less than 2 percent of the …
Human Genome Project (HGP) The project was coordinated by the United States Department of Energy and the National Institute of Health. The method involved the two major approaches- first identifying all the genes that express as RNA called Express sequence tags (EST). The second is the sequencing of the all set of genomes that contained the all the …
Regulation of Gene Expression All the genes are not activated constantly. The genes are needed only when proteins are needed. These are thus called regulatory genes and are made to function only when required and remain non-functional at other times. Such regulated genes, therefore, are required to be switched ‘on’or ‘off’ when a particular function is to begin or stop. These …
Salient Features of Genetic Code The code is triplet. 61 codons code for amino acids and 3 codons do not code for any amino acids; these are called stop codons (UAG, UGA and UAA). Codon is unambiguous and specific. It codes for just one amino acid. The code is degenerate; this means that some amino acids are coded by more than …
Genetic Code Genetic code is the sequence of nucleotides in DNA or RNA that determines the sequence of amino acids in a polypeptide chain. George Gamow suggested that genetic code should be a combination of 3 nucleotides to code 20 amino acids. H.G. Khorana developed a chemical method to synthesise RNA molecules with a defined combination of …
Translation It is the process of protein synthesis by reading the mRNA codons. It occurs in cytoplasm. Ribosomes are the sites for protein synthesis in a cell. Process of Translation Charging of tRNA: Binding of specific amino acid to the tRNA molecule. Initiation of polypeptide synthesis: Identifying the initiation codon on mRNA and attachment of the specific …
Transcription Transcription is the process where genetic information from a strand of DNA is copied to form the RNA. The RNA is formed as a complementary strand to the DNA strand. Here during the addition of bases in RNA, adenine forms a base pair with uracil instead of thymine. During transcription, one of the strands of DNA …
Enzyme Machinery and Process of DNA Replication The most important enzyme involved in DNA replication is the DNA polymerase. DNA replication is an energy dependent process. Replication begins on the specific site on the DNA, known as the origin of replication (ori). During the process of replication, the two DNA strands do not separate completely, the replication …
DNA Replication DNA replication is a process where two identical copies of DNA are produced from a single DNA molecule. It involves the separation of the two strands of a DNA helix to form two new DNA molecules. Out of the two new strands of DNA formed, one is identical to one of the parent …
Hershey-Chase Experiment Alfred Hershey and Martha Chase (1952) gave proof that DNA is the genetic material. In the experiment, bacteriophages (viruses that infect bacteria) were used. They grew some bacteriophages on a medium that contained radioactive phosphorus and some others on a sulphur-containing radioactive medium. The bacteriophages grown in the presence of radioactive phosphorus contained radioactive DNA. Radioactivity was not observed in the …
