NEET BIOLOGY

Detailed explanation-1: -In early bacterial genetics a cistron denotes a structural gene; in other words, a coding sequence or segment of DNA encoding a polypeptide.

Detailed explanation-2: -The correct option is C cistron. Cistron-segment of DNA which determines the synthesis of the complete polypeptide. Thus, it is considered as equivalent to a structural gene.

Detailed explanation-3: -A DNA sequence or cistron is composed of two parts; exons and introns. Exons are the coding sequences and introns are the non-coding sequences. A cistron consists of one gene, and can hence be called monocistronic (as compared to operons which are polycistronic).

Detailed explanation-4: -The main difference between a structural gene and cistron is that a gene is a nucleotide sequence responsible for the synthesis of an RNA whereas a cistron is a nucleotide sequence responsible for the synthesis of a polypeptide sequence of a functional protein.

Detailed explanation-5: -Answer is b) cistron is equivalent to structural gene in modern molecular biology. According to classical concept two or cistron may combine together to form a gene.