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Molecular Basis Of Inheritance

Question
CBSEENBI12002663

Polymase is formed by

  • several ribosomes attached to a single mRNA

  • many ribosomes attached to a strand of endoplasmic reticulum

  • a ribosome with several subunits

  • ribosomes attached to each other in a linear arrangement

Solution

A.

several ribosomes attached to a single mRNA

In prokaryotes, ribosomes attach to the 5 end of mRNA as soon as transcription begins. A bunch of ribosome moves along a single m RNA molecules adding 15 amino acids second to the polypeptide chain, almost the same speed at which RNA polymerase transcribes the mRNA. The group of ribosomes together with single mRNA molecules, they are translating is called polysome. The use of polysomes si advantageous to a cell since the overall rate of protein synthesis is increased compared to the rate that would occur if there were no polysomes.
In eukaryotic cells, the ribosomes are attached to rough endoplasmic reticulum by ribophorin protein.Electron microscopy reveals that membranes of homogenised reveal that membranes of homogenised endoplasmic reticulum disrupt to form closed vesicles called microsomes.