NEET BIOLOGY

Detailed explanation-1: -It synthesizes the RNA strand in the 5’ to 3’ direction, while reading the template DNA strand in the 3’ to 5’ direction. The template DNA strand and RNA strand are antiparallel. RNA polymerase always builds a new RNA strand in the 5’ to 3’ direction.

Detailed explanation-2: -Transcription and replication both occur in 5’-3’ direction. Thus, template DNA has 3’-5’ reading frame.

Detailed explanation-3: -DNA replication always happens in the 5’→ 3’ direction. This is because the enzyme DNA polymerase, responsible for adding nucleotides to the new strands being formed, can add nucleotides only to the 3’ end of an RNA primer.

Detailed explanation-4: -The need for accuracy probably explains why DNA replication occurs only in the 5′-to-3′ direction. If there were a DNA polymerase that added deoxyribonucleoside triphosphates in the 3′-to-5′ direction, the growing 5′-chain end, rather than the incoming mononucleotide, would carry the activating triphosphate.