Question

A nucleotide is about to be added to a growing strand of DNA. Which factor determines which type of nucleotide will be added?

A. Base-pairing rules

B. The type of cell in which replication is taking place

C. The length of the DNA strand

D. Random chance

Answer 1

Answer: The correct answer is- A) Base-pairing rules.

DNA replication is a biological process in which two identical replica of DNA are produced from single original DNA molecule through an enzyme called DNA polymerase.

The strands of double helical DNA are first separated so that the template DNA strands are exposed.

DNA polymerase adds nucleotides in the newly growing according to the Watson and Crick base pairing. The rules according to this base pairing are as follows-

1) Adenine pairs with Thymine ( through 2 bonds of hydrogen).

2) Cytosine pairs with Guanine ( through 3 bonds of hydrogen).