Question
Biology Question on the molecular basis of inheritance
A 'transcription unit' in DNA is defined primarily by the (i) promoter (ii) structural genes (iii) Okazaki fragments (iv) adenylate residues (v) terminator
A
(i), (ii) and (v) only
B
(ii), (iii) and (v) only
C
(iii), (iv) and (v) only
D
(ii), (iv) and (v) only
Answer
(i), (ii) and (v) only
Explanation
Solution
A transcription unit is a segment of DNA that takes part in transcription. It has three components: (i) a promoter (ii) a structural gene and (iii) a terminator. Besides a promoter, eukaryotes also ? require an enhancer. Promoter is located upstream of structural gene (at 5' end of coding strand). Terminator region is present downstream at ?3 end. Transcription factors attach at promoter region.