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.
What is Monera? Definition of Monera Monera is a historical biological kingdom encompassing prokaryotes, which are unicellular organisms lacking a distinct nucleus. This kingdom primarily included bacteria and archaea, and its members are characterized by the absence of membrane-bound organelles. Over time, taxonomic classifications have evolved, and the term “Monera” is less commonly used today. … Read more
Definition of Mesophyll Cells The mesophyll cell is a group of highly differentiated cells which make up the mesophyll layer in plant leaves. The mesophyll layer in the leaves of dicotyledonous plant species is made up two types of cells: the spongy, and the palisade. This makes the mesophyll a site of photosynthesis. These are … Read more
The study of embryology, also known as embryos, is a key element of evolution in biology and can identify the commonalities and differences between different species. The embryo of an organism refers to the fertilized egg that it progresses through the stages of development, which are unique to the particular species. In examining how the … Read more
What is Facilitated Diffusion? Facilitated diffusion Definition Facilitated diffusion is a passive transport process in which specific molecules move across a biological membrane with the aid of specialized transmembrane proteins, following their concentration gradient without the direct use of energy. Principle of Facilitated diffusion – How does facilitated diffusion work? The principle of facilitated diffusion … Read more
Definition of Simple diffusion Simple diffusion is one of the types of passive transport that is, as the name implies is the simple movement of solute that happens when the electrochemical potentials of one side of the permeable barrier differ. Principle of Simple diffusion/How does simple diffusion work? In free diffusion across a membrane, solute … Read more
Stratified squamous epithelium Definition Stratified squamous epithelium diagram and Structure Classification of stratified squamous epithelium The stratified squamous epithelium is divided into two classes based on the accumulation of keratin by the cells towards the surface; Keratinized stratified squamous epithelium Non-keratinized stratified squamous epithelium Function of stratified squamous epithelium Stratified squamous epithelium play an important … Read more
Overview of Kingdom Animalia The Kingdom Animalia is a large group of multicellular eukaryotic organisms that are heterotrophic in their nature. They get their food from outside sources. While they cannot create their own food and this is among the most characteristic traits of plant cells, animal cells do not have a cell wall like … Read more
Phylum Aschelminthes Definition Aschelminthes are pseudocoelomate. They are bilaterally symmetrical, triploblastic, non-segmented, vermiform, organ-system grade construction that includes full digestive tubes. Characteristics of Phylum Aschelminthes Classification of phylum Aschelminthes The phylum is a heterogeneous collection of animals, which is why it is classified differently by various Zoologists. The classification here is based on and on … Read more
Definition of Phylum Coelenterata (Cnidaria) The Coelenterata can be described as a diploblastic metazoa that has a the tissue grade having one nematocyst, and one gastrovascular cavity, or coelenteron. Characteristics of Phylum Coelenterata (Cnidaria) Classification of Phylum Coelenterata (Cnidaria) The phylum Coelenterata contains more than 11,000 species of which half are extinct. The classification used … Read more
Definition of Phylum Hemichordata Phylum Hemichordata is a small marine phylum of worm-like animals known as Acorn Worms. They are distinct from chordates and serve as important connecting links between vertebrates and invertebrates. Characteristics of Phylum Hemichordata Phylum Hemichordata exhibits the following characteristics: Some examples of Hemichordata include Balanoglossus, Saccoglossus, Rhabdopleura, Atubaria, and Dendrograptus. In … Read more