All living organisms are composed of cells and cell products. Each eukaryotic cell contains several cytoplasmic organelles. Among the organelles, endoplasmic reticulum performs as intracellular transport system for various substances and also helps to exchange the materials between nucleus and cytoplasm. Prokaryotic cells and RBC (red blood cell) do not have any endoplasmic reticulum. Endoplasmic … Read more
Golgi body is a parallelly arranged sac-like and flattened structure. It is bounded by membrane and is found in almost all eukaryotic cells. It is placed in the cytoplasmic matrix near the nucleus. It has various name such as Golgi apparatus, Golgiosome, Golgi complex, Lipochondira. In case of plant cell, it is also known as … Read more
There are approximately 8.7 million species on earth and their variety is simply astonishing. Besides, no two individuals of any animal-form are exactly alike. Hence, there must be some arrangement to group them in orderly categories to study the animal world. The diversity or differences also signify that organisms are really not so different from … Read more
A virus is an infectious biological agent of small size. The name ‘Virus’ comes from the Latin word meaning ‘poison’ or ‘slimy liquid’. The size of the viruses ranges from 20-300 nm. The chemical composition of all true viruses is nucleic acid either DNA or RNA and protein. They cannot multiply and continue the … Read more
Bacteria (singular-bacterium) are the microscopic unicellular and prokaryotic organisms. It is also known as a microbe. The term bacteria were first coined by F.J. Cohn in 1854. Bacteria come from the Greek word manning rod. It was discovered by Antonie Von Leeuwenhoek in 1976. It has a plant like cell-wall and autotrophic mode of nutrition. … Read more
The word ‘vitamin’ (Latin, vita, life+ amine) is derived from the original word “vitamine”, coined by Casimir Funk in 1912. Vitamin is an organic compound which is found in the food in variable and minute quantity and must be supplied to the animal organism from the external sources. It is a vital nutrient for an … Read more