Ribosomes, Biology

Ribosomes:     are minute nonmembranous  and dense spheroidal particles or  granules. First observed by   electron   microscopy by palade 1955. Being only about 200 to 250 a in diameter these are smallest, but most abundant of all cytoplasmic organelles. Every cell contains several thousands to millions of ribosomes. Most  of these  are linked  at the surface of endoplasmic reticulum  many  are free  in   the cytosol, and some  are found in the   in the nucleus and mitochondria  also  in  chloroplasts  of plant cells.

Structurally. Each ribosome has two parts a proximal larger subunit linked to the endoplasmic are composed of RNA and proteins approximately in equal amounts. The ribosomal RNA  ( rRNA)   has only four macromolecules .  Three in the larger subunit  and one the  smaller subnuits.   Considerable portion of these RNA molecules secondarily become  double stranded due to intermolecular the intermolecular base  pairing  so that  the molecules become 3 dimensional .The ribosomal protein   include 73 macromolecules 40 in  large in 33 in small subunits .

Ribosomal  subunits  are assembled from  their  component  r RNA  and protein  molecules  in the nucleolus of nucleus. These  are of the four r RNA  molecules are  synthesized  in the nucleolus . The   fourth is   synthesized by some chromosome outside the nucleolus. This and the 73 protein molecules synthesized in the cytoplasm migrate to the nucleolus for being incorporated in ribosomal subunits. The latter diffuse out into the cytoplasm and assemble to form ribosome's most of which link the endoplasmic reticulum.

Posted Date: 10/4/2012 1:47:16 AM | Location : United States







Related Discussions:- Ribosomes, Assignment Help, Ask Question on Ribosomes, Get Answer, Expert's Help, Ribosomes Discussions

Write discussion on Ribosomes
Your posts are moderated
Related Questions
Which is plant tissues specialized in covering? The dermal tissues or covering tissues of the plants are the epidermis (that covers the leaves and the young stems and shoots) a

Q What is the function of the skin in humans? The skin is the external covering of the body. In humans its major functions are protection and perception of information from the

How does the addition of a watery secretion to the contents of the gut help in the process of digestion?

Q. Definition of Osseointegration in microscopic biophysical? Osseointegration implies that at light microscopic and electron microscopic levels, the identifiable components of

Assume that you have 1M stock solutions of NaCl, KCl, and CaCl2. If the ion concentrations in human plasma are 120 mM Na+, 12mM K+, and 2 mM Ca+, compute the volumes of the stock s

Determine the significance of Mesoglea. The jellylike layer found between endodermal and ectodermal cell layers of diploblastic organisms. It acts as a type of cement holding t

What is the difference between carriers of HIV and AIDS patients? A person can be a carrier of the HIV without necessarily being affected by the immunodeficiency syndrome at t

State the definition of soil The definition of soil has changed a great deal from a thin "outer layer of  Earth's crust" to "a collection of natural bodies on the surface of th

Ratios of the bases in different samples of nucleic acid yielded the following results: a.  A + C    =   0.6         b.     A  +  C    =  1            c.       A  + G    =  1.2

1. Compute the mean energy per nuclear disintegration, A, for 99m TC if 2.0 x 10 9 Bq of this isotope is injected into a patient. Assume that one-half of the administered dose is