Avatar for Sourav Pan

Sourav Pan

Founder of Biology Notes Online, Biology & Microbiology Educator, M.Sc. in Microbiology
Expertise
Microbiology, Immunology, Cell Biology, Molecular Biology, Genetics, Biotechnology, Biochemistry, Botany, Zoology
Education
University of Calcutta
Profile Last Updated: August 10, 2026

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.

DNA – Definition, Structure, Properties, Types, Functions

DNA - Definition, Structure, Properties, Types, Functions

What is DNA? DNA is a polymer of deoxyribonucleotides stuck together (or simply deoxynucleotides). It is made up of deoxyadenylate (dAMP), deoxyguanylate (dGMP), deoxycytidylate (dCMP), and deoxythymidylate (dTMP) units (dTMP) (Some authors prefer to use TMP instead of deoxythymidylate because it is only found in DNA.) History of DNA The history of DNA begins with … Read more

Experiments on DNA – Watson and Crick, Griffith, Chargaff, Hershey and Chase, Avery, McCarty, and MacLeod 

Experiments on DNA Structure

Many individuals believe that in the 1950s, American biologist James Watson and English physicist Francis Crick discovered DNA. In actuality, this is not true. DNA was discovered by the Swiss chemist Friedrich Miescher in the late 1860s. Then, in the decades that followed Miescher’s discovery, other scientists, notably Phoebus Levene and Erwin Chargaff, conducted a … Read more

Hershey–Chase experiment On DNA

Hershey–Chase experiment On DNA

Hershey–Chase experiment Experiment DNA as Genetic Material Observation Conclusion Why is DNA Considered a Genetic Material? It was found that DNA was the most important part of most species’ genes. There were some important exceptions, such as viruses whose genes were made of RNA. But what makes DNA different from other molecules that can be … Read more

Nucleotides and Nucleosides – Definition, Structure, Function, Types

Nucleotides and Nucleosides - Definition, Structure, Function, Types

What is Nucleotide? Nucleotide Structure The structure of a nucleotide is simple, but the structure they can make when they come together is complicated. This molecule is made up of two strands that wrap around each other. Hydrogen bonds hold the structure together in the middle. Each nucleotide has a specific shape that makes this … Read more

DNA Recombination – Definition, Mechanisms, Types

DNA Recombination - Definition, Mechanisms, Types

DNA recombination is the process in which the genetic material (DNA) is exchanged between two DNA molecules. It is the natural method for reshuffling of genes, and it is observed in most living organisms. It is the process where the DNA strand is broken and then repaired, and new combination of alleles is formed. It … Read more

Ecological Succession – Definition, Types, Mechanism, Examples

Ecological Succession - Definition, Types, Mechanism, Examples

What is Ecological Succession? Ecological Succession Definition Ecological succession is the systematic and predictable process by which species composition in an ecosystem changes over time, progressing from initial colonization to a mature and stable community. Characteristics of Ecological Succession Ecological succession is a fundamental concept in the realm of ecology, delineating the sequential transformation of … Read more

Pyramid of Numbers – Definition, Types, Importance, Examples

Pyramid of Numbers - Definition, Types, Importance, Examples

What is Pyramid of Number? The Pyramid of Numbers is a graphical representation used in ecology to illustrate the distribution of various species in different trophic levels of a food chain. This pyramid provides a quantitative analysis, showing the number of individual organisms present at each trophic level. Unlike other ecological pyramids which might consider … Read more

Microbial interaction – Definition, Types, Characteristics, Examples

Microbial interaction - Definition, Types, Characteristics, Examples

Microbial interaction is a biological interaction in which the effect of microorganisms on other biotic components of an ecosystem can be investigated. Microbiology is the study of microorganisms, and microbial ecology is the study of microbial interactions within an ecosystem. Positive and negative microbial interactions are possible, and microbes can affect (positively or negatively) other … Read more

Carbon Fixation – Process, Pathways, Importance

Carbon Fixation - Process, Pathways, ImportanceCarbon Fixation - Process, Pathways, Importance

What is Carbon Fixation? Carbon Fixation Definition Carbon fixation is a biological process where atmospheric carbon dioxide (CO2) is converted into organic compounds, primarily by plants, algae, and certain bacteria. This process is a key component of photosynthesis, enabling the incorporation of inorganic carbon from the atmosphere into organic molecules like carbohydrates, thereby playing a … Read more