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.
typical flora of skin, hair, and nails is the stable community of microorganisms—mostly bacteria and fungus—that live on the outside surfaces of the human body without causing damage under typical circumstances. These communities, sometimes referred to as the skin microbiome, occupy ecological niches, fight against infections, and generate molecules that stop microbial invasion, therefore safeguarding … Read more
The human body is home to trillions of tiny organisms, like bacteria, fungi, and viruses, that live on the skin, in the mouth, gut, and other areas. This community of microbes is called the human microbiome. Most of these organisms aren’t harmful—in fact, many are essential for health. They help digest food, produce vitamins, and even … Read more
What is Peripheral Nervous System? The peripheral nervous system acts as a bridge between the brain, spinal cord, and the rest of the body. Think of it as a network of pathways that carry messages back and forth. While the brain and spinal cord form the central command center, the peripheral system handles communication with … Read more
What is Rhizosphere? The rhizosphere is the small area of soil around plant roots that is directly affected by root secretions and the microbes that live there. Usually goes about one millimeter from the root surface and includes soil that sticks to the roots and can be easily shook off. Root exudates and rhizodeposition: Roots … Read more
What is Dutch elm disease (DED)? A deadly fungal disease that infects elm trees and stops water from flowing through their vessels, causing them to wilt and die. The main cause is Ophiostoma ulmi and Ophiostoma novo-ulmi. Dutch phytopathologists Schwarz and Buisman found it in the Netherlands in the early 1920s. It was brought to … Read more
What is Fusarium Wilt? Fusarium wilt is a prevalent soil-borne fungal affliction produced by Fusarium oxysporum, affecting various plants such as tomatoes, bananas, cucumbers, and beans, resulting in progressive wilting and eventual plant mortality. Causative Agent of Fusarium Wilt Primary causal organism – Fusarium oxysporum is the dominant species responsible for Fusarium wilt across diverse … Read more
Pollen-pistil interaction is a critical phase in plant reproduction, acting as a sophisticated biological dialogue between male pollen grains and the female reproductive structure, the pistil. When pollen lands on the stigma—the sticky tip of the pistil—it doesn’t immediately guarantee fertilization. Instead, the pistil initiates a series of biochemical checks to assess compatibility. These interactions … Read more
What is Electroporation? Electroporation is a fascinating technique that temporarily makes cell membranes more permeable by applying brief electric pulses. This method, widely used in labs and medical settings, allows substances like DNA, drugs, or proteins to enter cells by creating tiny pores in the membrane. Imagine zapping cells with a controlled jolt of electricity—this … Read more
What is Microsporogenesis? Definition of microsporogenesis Microsporogenesis is the process in which diploid microspore mother cells undergo meiosis to form haploid microspores, which eventually develop into pollen grains in plants. Where does microsporogenesis occur? Structure of Stamen Structure of microsporangium Process of Microsporogenesis in Plants In flowering plants, microsporogenesis is the process by which precursors … Read more