Question

Organelle and prokaryotic ribosomes are generally
A) 80S
B) 100S
C) 70S
D) 45S

Answer 1

Hint:Transcription of multiple ribosome gene operons results in the synthesis of ribosomes in the bacterial cell.

Complete answer
>Ribosomes are tiny particles found scattered in the cytoplasm and attached to certain organelles.
>They bind messenger RNA and transfer RNA for the synthesis of proteins and polypeptides.
>Prokaryotes have 70S ribosomes. it is made up of 50S and 30S subunits. The 50S subunit is divided into 23 S and 5S rRNA. While 16S rRNA is the content of the 30S subunit.
>Decoding the message and formation of peptide bonds are the two main functions of a ribosome. The subunits of ribosomes are basically ribonucleoprotein particles of unequal size. Each subunit has its own rRNA and ribosomal proteins or r-proteins.
>Ribosomes are either free or membrane bound. They differ only in their spatial distribution but are identical in structure. The existence of a ribosome will be free or membrane bound depending on the presence of ER targeting signal sequence.

Hence the correct answer is option C.

Note: Free ribosomes have the liberty to float anywhere in the cytosol whereas membrane bound ribosomes are strictly attached to the membranes of cell organelles like endoplasmic reticulum. It is often called an organelle although the word organelle is specific to parts of the cell that has phospholipid membranes.