Sourav Pan is the founder and sole author of Biology Notes Online. He holds a Bachelor of Science (B.Sc.) degree and an M.Sc. in Microbiology from the University of Calcutta. He creates educational resources covering microbiology, immunology, biotechnology, genetics, cell biology, botany, zoology, and other life-science subjects.
His goal is to make complex biological concepts easier to understand through well-structured, student-friendly articles based on academic textbooks, peer-reviewed research, and authoritative scientific sources. In addition to writing new content, he regularly reviews and updates articles to improve their accuracy, clarity, and educational value.
Name Cas9 endonuclease Alternative name spCas9/spyCas9 Organism Streptococcus pyogenes serotype M1 Molecular weight ~163KDa Gene cas9 Location on chromosome 0.85 to 0.86Mb Protein CRISPR-associated endonuclease Cas9/Csn1 Cofactor Mg2+ Biological processing Interference- defense response to phage.Maintaining CRISPR repeat sequences Functions DNA and RNA bindingMetal ion binding3’-5’ exonuclease activityEndonuclease activity What is Cas9 Protein? Structure of Cas9 HNH … Read more
What is dna repair mechanism? DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. dna repair definition Types of dna repair mechanism There are present four types of DNA Repair System such as; 1. Mismatch Repair System Enzyme participate in dna … Read more
Mode of DNA replication Imagine yourself in 1953, right after the discovery of the double helix structure of DNA. What are some burning questions you and other scientists might have? One big question concerned DNA replication. The double helix shape of DNA gave a tantalising hint about how copying might happen. It seemed likely that … Read more
What is cDNA library? Principle of cDNA library Process involved in the construction of cDNA library 1. Extraction of mRNA from the eukaryotic cell 2. cDNA construction In the process of creating cDNAs, there’s different approaches. They are described as follows: a. The RNAse method Step I: Annealing: Step II: Replacing RNA strand with DNA … Read more
A ribonucleoprotein known as telomerase, terminal transferase adds a repeat sequence of telomeres to the 3′ end of chromosomes, the length of which varies depending on species. In most eukaryotic organisms, the chromosomal ends are capped by a repeating sequence known as a telomere. Telomeres prevent DNA damage and chromosomal fusion at the chromosome’s end. … Read more
What is SOS Response or SOS Repair? Definition of SOS Response or SOS Repair The SOS response or SOS repair is a cellular mechanism activated in response to DNA damage, where the cell cycle is temporarily halted to facilitate DNA repair and mutagenesis. Central to this system is the RecA protein, which, when stimulated by … Read more
What is cDNA? cDNA synthesis principle cDNA synthesis steps There are different steps for synthesis of cdna such as; cDNA synthesis protocol 1. Prepare sample 2. Remove genomic DNA 3. Select reverse transcriptase Common reverse transcriptases and their attributes. AMV reverse transcriptase MMLV reverse transcriptase Engineered MMLV reverse transcriptase(e.g., Invitrogen SuperScript IV Reverse Transcriptase) RNase … Read more
Transcription refers to the process in which the information contained in the DNA strand is transformed into a new messenger RNA molecule (mRNA). In prokaryotic cells, transcription occurs in three stages called the initiation, the elongation, and the termination.
The process of DNA transcription also referred to as RNA synthesis , is the process where genetic information in DNA is transformed into messenger (mRNA) (mRNA) through an enzyme known as RNA polymerase.
Ribonucleic acid (RNA) Polymerase (RNAP) enzyme is a multi-subunit enzyme which uses its function to catalyze the transcription process RNA produced from DNA template.
