Biology Notes

Natural Selection Definition Natural selection is the process by which an organism adapts to its changing environment by making selective changes to its genotype or genetic makeup. Natural selection, along with mutation, genetic drift, and migration, is one of the four fundamental mechanisms of evolution. During his evolutionary investigations, Charles Darwin popularised the concept of … Read more

Definition of Pseudostretified Columnar Epithelium The pseudostratified columnar epithelium is a form of epithelium made up of a single layer of cells that appears to have numerous layers due to the presence of distinct nuclei at different levels. Even though it appears as a stratified epithelium in crosssection, this epithelium is histologically a simple epithelium. … Read more

Simple Cuboidal Epithelium Definition Simple cuboidal epithelium is a form of simple epithelium made up of cube-shaped cells with rounds and a nucleus that is more or less in the centre. They are generally created to better suit the function of specific organs. All of the cube-shaped cells are directly linked to the basement membrane … Read more

Transitional Epithelium Definition  Transitional epithelium is a sort of stratified epithelium made up of numerous layers of cells whose shape changes depending on the organ’s function. When the epithelium is relaxed, it appears cubical or round, with the exception of the apical layer, which appears flattened when stretched. Because this epithelium is almost exclusively found … Read more

Microvilli  Definition Microvilli are minute projections that exist in, on, and around cells, to put it simply. They can be found alone or in combination with villi (projections of some mucous membranes, most specifically of the small intestine, which are tiny folds that project out like numerous fingers). Microvilli are even tiny folds that shoot … Read more

What is Exocytosis, and How does it work? Exocytosis, as contrast to endocytosis, is a process that uses energy to transfer items from the inside of the cell to the outside of the cell. As a result, it is an active transport system that is the polar opposite of endocytosis. In this technique of exocytosis, … Read more

Active and Passive Transport Definition  The two main biological processes that give nutrients, water, oxygen, and other vital molecules to cells, as well as remove waste products, are active and passive transport. Both active and passive transportation have the same goal, but they move in different ways. Since active transport engages the movement of biochemicals … Read more