Question

Balbiani rings (puffs) are sites of
A. DNA replication
B. RNA and protein synthesis
C. Synthesis of polysaccharides
D. Synthesis of lipids

Answer 1

Hint: A Balbiani ring is a large chromosome puff present in the polytene chromosome. These chromosome puffs are used to refer to the diffused and uncoiled regions of the genome present in the polytene of the cell.

Complete answer:
Cell division is a very important process for the survival of organisms on this earth. Because cell division is required to carry out reproduction, to increase biomass, to heal wounds and there are so many other advantages of cell division.
Polytene chromosomes are the groups of the large set of chromosomes having thousands DNA strands. These structures of the chromosome groups are very helpful for tissues like salivary glands of the different organisms.
This uncoiling of the chromosomes, causes an increase in the volume of the nuclei of the cell and helps in the expansion of the cell which is required for the cell division. Polytene cells also have more metabolic activities due to presence of the multiple copies of the genes and chromosomes.
Another function of the polytene chromosome is involvement of inter-bands in the interactions with the active chromatin proteins which help in nucleosome remodelling and it acts as binding site for RNA polymerase II.
Balbiani rings are the sites for active RNA synthesis that means site for transcription, at the polytene chromosomes of the nucleus. Thus, we can say that Balbiani rings are involved in the synthesis of RNA and proteins.

Hence, option ‘B’ is correct.

Note: For cell division, DNA or genetic material of an individual should be doubled which takes place by replication. Then cells undergo cell division according to cell cycle which involve different phases that is, G1 phase, S-phase, G1 phase, and M-phase.