Question

Hair pin loops are present in
A. DNA
B. RNA
C. Lampbrush chromosomes
D. Protein

Answer 1

Hint:- The nucleus of most of the organisms contains genetic information in the form of DNA. This DNA further replicates and then undergoes the process called, 'Transcription.” During the transcription, DNA is converted to RNA. After the transcription, another process called, 'Translation' occurs which determines the polypeptide chain synthesis.

Complete step-by-step solution:- The transcription is an enzymatic process that shows slight differences in eukaryotes and prokaryotes. Both prokaryotes and eukaryotes require an enzyme called RNA polymerase for the transcription process. The segment of the DNA that is involved in transcription is referred to as the 'transcription unit.” In both the prokaryotes, and eukaryotes a specific sequence of nucleotides called the promoter sequence is present on which the enzyme RNA polymerase binds and initiates the transcription process. Transcription terminates when RNA polymerase reaches the terminator site.
Termination of transcription requires a protein that binds to RNA before reaching the terminator site called rho-factor in the prokaryotes. In prokaryotes, termination of transcription may be rho — dependent or independent but in eukaryotes it is always rho- independent. The rho- independent termination of transcription in prokaryotes is achieved by the formation of Hairpin loop-like structures also called G-C rich loops or the Stem loops. These loops are formed when the two complementary nucleotide bases, pairs with each other in a strand of mRNA formed.
Thus, the mRNA strand got separated from the transcription unit of DNA and the transcription is terminated. So the hairpin loops are seen in mRNA during the termination of transcription. Lamp brush chromosomes are the chromosomes that are formed by the active and excessive transcription of many genes during the first meiotic division. Thus, the correct answer is option B.

Note:- In prokaryotes, the rho-factor has helicase-like activity as it breaks hydrogen bonds between RNA-DNA hybrids. In prokaryotes, fully functional mRNA is produced. Whereas in eukaryotes full functional mRNA is not produced. Thus, the m-RNA of the eukaryotes is called a pre-mRNA or hnRNA and it requires further processing which is carried out in nucleoplasm.