Question

Balbiani rings are sites of

• A. Lipid synthesis
• B. Nucleotide synthesis
• C. Polysaccharide synthesis
• D. RNA and protein synthesis

Answer 1

The correct option is D

RNA and protein synthesis

The correct option is D.

Explanation of correct option:

1. The polytene chromosomes, in some developmental stages, comprise conspicuous swellings known as chromosome puffs.
2. The larger swellings are known as Balbiani rings.
3. In the region of a Balbiani ring, the strands of DNA become active, uncoil, and generate several copies of mRNA (messenger ribonucleic acid).
4. The mRNAs may get briefly stored in the puff and they may go through the process of transcription to produce proteins.
5. Therefore, Balbiani rings are the locations of RNA and protein synthesis.

Explanation of incorrect options:

Option A:

1. The prime site of lipid synthesis is the endoplasmic reticulum.
2. A network of membranous tubules within the eukaryotic cell’s cytoplasm, that is continuous with the nuclear membrane is called the endoplasmic reticulum.

Option B:

1. The nucleotides can be further differentiated into pyrimidines and purines.
2. In the complex multicellular species, they both are mainly produced in the liver, the process is known as de novo nucleotide synthesis.

Option C:

1. The synthesis of polysaccharides takes place in the Golgi apparatus.

Final answer: Balbiani rings are the sites of RNA and protein synthesis.