NUCLEUS
abidaNucleus contains most of the genes that control the cell. It is the most conspicuous organelle in the eukaryotic cell. Its average diameter is about 5. It performs two major…
ANIMAL SYSTEMATICS (CLASSIFICATION)
saadiaANIMAL SYSTEMATICS (CLASSIFICATION) Following groups used in animal classification: 1. Monophyletic Groups: The groups showing similarities due to single ancestors are called monophyletic groups. The classification based on monophyletic groups…
VACOULES AND VESICLES
Vacuoles and vesicles are membrane-enclosed sacs within the cell. But vacuoles are larger than vesicles. Vacuoles have various functions. They form food by phagocytosis. Many freshwater protists have contractile vacuoles…
CENTRIOLES AND MICROTUBULE ORGANIZING CENTERS
Microtubule-organizing centers The specialized non membranous regions of cytoplasm near the nucleus are the microtubule-organizing centers. These centers contain dense material. This material gives rise to a large number of…
THE CYTOSKELETON
The cytoskeleton is a network of fibers suspended through the cytoplasm. There are three fibers in the cytoskeleton. These are microtubuies, microfilaments and intermediate filaments. Functions of Cytoskeleton - The…
MITOCHONDRIA
Mitochondria are commonly called as power house of the cell. They provide energy transuding system. This system is used to change the food into chemical energy by oxidative phosphorylation ATP…
LYSOMES
Lyso ome is a membrane-enclosed bag of hydrolytic enzymes that the cell uses to digest macromolecules. The lysosomal enzymes can hydrolyze prote ns. polysaccharides, fats, and nucleic acid. These enzymes…
THE GOLGI APPARATUS
The Golgi apparatus consists of flattened membranous sacs. They look like a stack of pita bread. A cell may have several interconnected stacks. Each cisterns in a stack consists of…
THE ENDOPLASMIC RETICULUM (ER)
The word endoplasmic means "within" the cytoplasm. The word reticulum means "network." The ER consists of a network of membranous tubules and sacs called cisternae. The ER are extensive in…
RIBOSOMES
Ribosomes are non-membranous bounded strOctures. Ribosomes are the sites where the cell synthesizes proteins according to genetic instructions. A bacterial cell may have a few thousand ribosomes.But a human liver…