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.
Definition of Simple columnar epithelium The simple columnar epithelium, which is one type of epithelium, is made up of a single layer consisting of long, elongated cells. These cells are located in areas where absorption or secretion are the primary functions. The cells of the columnar epithelium can also be modified, just like cuboidal epithelium. … Read more
Definition of p-value The p-value, or estimated probability represents the most reliable probability of providing the lowest amount of significance, that the null hypothesis isn’t the case. Formula of p-value How to find p-value? P-values can be determined through comparing test results against the table of p-values for various scores. The scores calculated by the … Read more
What is Stratified cuboidal epithelium? Definition of Stratified cuboidal epithelium Stratified cuboidal epithelium is a type of epithelial tissue characterized by multiple layers of cells, with the surface layer consisting of cube-shaped cells. It is primarily found in glandular structures and plays roles in protection, selective absorption, and secretion. Stratified cuboidal epithelium labeled Stratified cuboidal … Read more
Definition Glandular epithelium The glandular epithelium comprises a set of tissues that is not the epithelium that covers and lines that is specifically designed to secrete and produce of different macromolecules. Due to its primary role it is often referred to as”the secretory epithelium. It is situated under the lining and covering epithelium. It may … Read more
Learn what a hypotonic solution is, how it affects cells through osmosis, its effects on plant and animal cells, common examples, uses, and key differences.
To function properly, cells must be kept turgid. To function properly, a well-watered plant will grow and produce fruits and flowers. A plant that is not watered for several days will wilt and eventually die. This happens because water leaves the cell and causes the cell to lose its turgidity. Based on the concentration of … Read more
What is An Autotroph? Definition of Autotroph An autotroph is an organism that can produce its own complex organic compounds (like carbohydrates) using simple substances such as carbon dioxide, typically through processes like photosynthesis or chemosynthesis, without relying on external sources for carbon or energy. Types of Autotrophs Autotrophs, which are organisms that make their … Read more
What is Heterotroph? Definition of Heterotrophs Heterotrophs are organisms that rely on eating other living things for their nutrition and energy, as they cannot produce their own food. Types of Heterotrophic Nutrition In the natural world, living things use different ways to get their food when they can’t make it themselves. These are the main … Read more
What are Phylum Mollusca? Definition of Mollusca (Mollusks) Mollusca, commonly known as mollusks, is a large phylum of invertebrate animals characterized by a soft body that is often protected by a hard shell. This diverse group includes species such as snails, slugs, clams, octopuses, and squids. Mollusks are known for their unsegmented bodies, bilateral symmetry, … Read more
Definition of Phylum Nematoda Nematodes (Gr. nema thread+ form) are often referred to by various names, such as threadworm, non-segmented roundworm or pinworm. They are distinct from flatworms and higher segmented anelids. Characteristics of Phylum Nematoda Classification of Phylum Nematoda Nematoda is one of the most diverse phyla. At present, there are approximately 15,000 species. … Read more