Q. Statements I. The four nucleotide bases are not necessarily present in DNA in exact equal proportions. II. The total amount of purines are equal to the total amount of pyrimidines. III. DNA ligase enzyme act to hydrolyse or breakdown a polynucleotide chain into its component nucleotides. IV. Nuclease enzymes are capable of restoring an intact DNA duplex. Of the above statements
A) II is correct, but I, III and IV are wrong
B) I and II are wrong but III and IV are correct
C) I, II and III are correct but IV is wrong
D) I and II are correct but III and IV are wrong
Explanation
DNA fragments can be rejoined under the appropriate renaturation conditions by using the enzyme DNA ligase to reform the missing phosphodiester linkages in each strand. An exonuclease in an enzyme which degrades nucleic acids from ends, while an endonuclease is an enzyme which degrades nucleic acid by making internal cuts.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.