Organelles in a Cell Online Biology Tutors Tutorpace

Organelles in a Cell Online Biology Tutors Tutorpace Cell is the basic structural and functional unit of living organism.Cell consists of many cell organelles. The part of a cell which has a definite shape, structure and function is called an organelle. Cell wall is a semi rigid permeable membrane composed of complex polysaccharide called cellulose. It gives strength and rigidity to the cell, allows free passage of substances through it.Allows free passage of substances through it. Cell membrane is differentially permeable two layered membrane composed of fats and proteins. It regulates the entry and exit of substances in and out of the cell. Endoplasmic reticulum is a network of tubular membrane. If ribosomes are present on them they are rough and if it is absent it is smooth. They provide a pathway for distribution of nucleus nuclear material and provide supporting skeletal frame work of the cell. Ribosomes are single walled dense spherical bodies composed mainly of RNA. Occurs freely in the matrix or attached to endoplasmic reticulum.It is the site for protein synthesis Mitochondria are double walled, inner membrane thrown into folds called cristae. They release energy and synthesize respiratory enzyme .Golgi apparatus consists of tubules, vesicles and vacuoles. They secrete enzymes and hormones Lysosomes are sac like vesicles which help in the synthesis of digestive enzymes, provide energy during cell starvation. Centrioles are micro tubular structures found in small clear area of the cytoplasm called centrosome. They initiates cell division. Nucleus- It is the brain of the cell living certain dense bodies called nucleoli and a network of thread like structures called chromatin which contains the DNA. They regulates growth and reproduction of cells, Chromosomes in nucleus bears hereditary materials and Nucleolus stores proteinsVacuoles are fluid filled spaces enclosed by membrane.