Cell Biology Notes
Cell Organelles Definition The cell is the basic unit of organization or structure of living matter bound by the semipermeable membrane and is capable of self-replicating in a medium free of other living systems. Cell organelle is the cellular component that can be both membranous and non-membranous present within a … Read more
What are Cilia? The word cilia is derived from the Latin word cili which means eyelash. In the Latin word, Flagella means little whip. They are microscopic which can’t be seen with naked eyes. They have the contractile property and are filamentous processes of the cytoplasm. Food currents are created … Read more
What are Microtubules? The cytoskeleton of the eukaryotic cell is made of proteins that give shape to it. The three types of protein that help in the organization of the cell are microtubules, intermediate filaments, and microfilaments. This cytoskeleton is absent in the bacteria. Tubulin is present in the microtubules. … Read more
What are Centrioles and Basal Bodies? In some eukaryotic cells, near the nucleus, there is the presence of two cylindrical structures. They are rod-shaped and microtubular. They are known as the centrioles. A limiting membrane is absent in it. DNA or RNA is also absent in it. It also forms … Read more
What are Lysosomes? The name Lysosome is derived from the Greek word where “lyso” means digestive and “soma” means body. Lysosomes are membrane-bound vesicle which is tiny in the structure. Lysosomes are involved in intracellular digestion. Different kinds of hydrolytic enzymes are present in the lysosome. Under acidic conditions, these … Read more
What is Ribosome? The ribosome is a large complex that is made from dozens of small proteins. These small proteins are ribosomal proteins. It consists of many several RNA molecules which are called ribosomal RNAs (rRNAs). The word ribosome is made up of ribo+somes. “Ribo” stands for ribonucleic acid. In … Read more
What is Rough Endoplasmic Reticulum (RER)? The endoplasmic reticulum (ER) which consists of ribosomes on its surface is known as the rough endoplasmic reticulum. So it is also called the granular endoplasmic reticulum. Translocon is the binding site of the ribosome on the rough endoplasmic reticulum. These ribosomes look like … Read more
What is Nucleus? Nucleus Properties The Nucleus is an important cell organelle that is present in the eukaryotic cell. It is derived from the Latin word, ‘nucleus’ or ‘ nuculeus’. It means kernel or seed. It is first described by Robert Brown as the cell organelle. It was named chromatin … Read more
Cell membrane (Plasma membrane) The outer thin membrane or the layer of the living cell is known as the cell membrane. It is also known as the plasma membrane in animal cells. In the plant cells, it is known as plasmalemma. The term cell membrane was given by Nageli and … Read more
Mitochondria Properties Mitochondria is the cell organelle which is filamentous and granular structure. It is present in higher plants, animals, and some microorganisms. It is absent in bacteria but is found in algae, protozoa, and fungi. To carry out the energy metabolism, mitochondria have got the lipoprotein framework. It consists … Read more
Golgi body Properties Golgi body or complex is an organelle that is bound by a membrane in eukaryotic cells. The Golgi body is also called as Golgi apparatus, Golgi complex, lipochondrion, Barker’s body, Dalton Complex, and Apparato Reticulare. Golgi complex may have distinct subunits called Golgiosomes, idiosomes, or dictyosomes. It … Read more
Endoplasmic Reticulum (ER) In 1897, Garnier observed the Endoplasmic Reticulum (ER) with a light microscope. Ergastoplasm was the term coined by him. In 1945 Porter first reported the Endoplasmic Reticulum. It was discovered independently by Porter and Thompson. It is a continuous membrane system. At one end, it connects the … Read more
Capsule, Flagella, Pili (Fimbriae), Glycocalyx (Slime Layer) Capsule The capsule is a gelatinous layer covering the entire bacterium. It is composed of polysaccharide, except in the anthrax bacillus, which has a capsule of polymerized d-glutamic acid. The sugar components of the polysaccharide vary from one species of bacteria to another … Read more
Cell inclusion Bodies Bacterial cell inclusion bodies are otherwise known as granules. Electron microscopic observation reported the presence of both organic and inorganic granules inside the bacterial cell. These granules function as energy storage and these are also involved in reducing osmotic pressure. Some of these granules are found freely … Read more
Nucleus The nucleus is a specialize membrane-bound structure or organelle. It is the controlling center of eukaryotic cells. It is a characteristic feature of eukaryotic cells and is absent in prokaryotes like bacteria and viruses. It contains most of the genetic material of an organism. Most of the eukaryotic cells … Read more