Modern understanding of DNA has evolved from the discovery of nucleic acid to the development of the double-helix model. In 1869, Friedrich Miescher began working with white blood cells which are the major component of pus from infections. He collected a lot of pus from bandages at the local hospital. He used a salt solution to wash the pus off the bandages.
The Lac operon, proposed by Francois Jacob and Jacques Monod, is predominantly found in prokaryotes like E. coli, representing the first identified gene regulatory process in bacteria. Comprising an operator, promoter, three structural genes (lacZ, lacY, lacA), and a terminator, the operon governs the regulation of lactose, including its transport and metabolism. The structural genes … Read more
Translation is the term used to describe the polymerization of amino acids into a polypeptide, constituting the biological process by which proteins are synthesized is called translation. Translation happens in following main steps: Initiation, Elongation, Translocation, Termination Initiation: 1. The initiation phase involves the assembly of ribosomes around the target mRNA. 2. Ribosomes, known as … Read more
Transcription The Central Dogma elucidates the process by which DNA encodes proteins, unfolding in three phases: replication, transcription, and translation. Following DNA replication of its two strands, information is transcribed into RNA. The process of transcription in protein synthesis is as follows: 1. Transcription is the initial step in protein synthesis, where m-RNA is formed … Read more
DNA replication DNA replication is the biological mechanism that generates two identical copies of DNA from a single original DNA molecule. The steps involved in the process of DNA replication are as follows: 1. Helicase initiates DNA replication by unzipping the double helix, breaking hydrogen bonds between complementary bases. 2. This separation forms a replication … Read more
The Human Genome Project constituted a collaborative and global scientific endeavor aimed at elucidating the sequence of nucleotide base pairs comprising human DNA. Its overarching objectives included the comprehensive identification and mapping of all human genome genes, undertaken with a dual focus on both the physical and functional dimensions of genetic information. Following are the … Read more
The role of lactose in in ‘lac operon’ are-: 1. A low level of beta-galactoside permease enzyme persists in the cell even when the Lac operon is inactive, allowing minimal lactose entry. 2. Lactose binding to the repressor renders it inactive. 3. The repressor-lactose complex loses its ability to bind to the operator gene, leading … Read more
DNA fingerprinting, is a technique that analyzes the unique characteristics of DNA molecules to identify individuals. It creates a distinct DNA profile, much like fingerprints, allowing for individual identification and analysis. Applications of DNA finger printing: 1. Forensic science aids in pinpointing potential suspects. 2. Establishing blood relationships is a key function. 3. Identification and … Read more
The several key features of the genetic code are: 1. Commaless Structure: The genetic code exhibits a commaless arrangement, where triplet codons on m-RNA follow one another seamlessly without gaps. This absence of commas in the sequence is a distinctive feature. 2. Non-ambiguous Nature: Each codon holds the unique ability to specify a particular amino … Read more
1. Eukaryotic cell DNA (2.2 meters) undergoes condensation, coiling, and supercoiling for efficient packaging in the nucleus (10-16 meters). 2. DNA associates with both histone and non-histone proteins. 3. Histones, positively charged basic proteins, are rich in lysine and arginine amino acid residues. 4. The nucleosome consists of a nucleosome core with two molecules each … Read more
The nucleosomal ‘core’ histones consist of two molecules each of H2A, H2B, H3, and H4 histone proteins.