Answer: 2.2 metres.
- A 0.22 millimetres
- B 22 centimetres
- C 2.2 metres
- D 22 metres long
Correct answer: C. 2.2 metres
Explanation: The 6.6 x 10<sup>9</sup> base pairs in a human diploid cell give a total DNA length of about 2.2 metres when fully stretched.
Helicase unwinds the double helix at the replication fork; one new strand (leading) is synthesised continuously toward the fork, while the other (lagging) must be made in short, separate Okazaki fragments because DNA polymerase only adds nucleotides 5'→3'.
Concept context
DNA structure, replication, transcription, translation, the genetic code, and gene regulation (lac operon). The single most important chapter for NEET molecular biology.