Question

In DNA replication, the Okazaki fragments on the lagging strand are joined together by,
A. DNA polymerase
B. primase
C. helicase
D. DNA ligase

Answer 1

Hint: The experiment which was done by MESELSON and STAHL in the nitrogen medium of the replication process of DNA or duplication of DNA, the discontinuous segment of DNA is called an Okazaki fragment. They are joined by a molecular glove.

Complete answer:
 As we know in DNA replication process two-strand are formed called as leading strand and lagging strand in which continuous part becomes leading and discontinuous become lagging which contains approximately 150 to 200 inactivated base pair of nucleotide base pair called an Okazaki segment.
These segments are combined from a strand called lagging strand. For this combining process, a joining enzyme is required which is called as DNA LIGASE or commonly known as a molecular glove.

Hence, the correct answer is option (D).

Additional information:
PRIMER: A primer may be a short, single-stranded DNA sequence employed in the polymerase chain reaction (PCR) technique for biosynthesis. In the PCR method, a pair of DNA primers are employed to hybridize with the sample DNA and define the region of the DNA that may be amplified. Primers also are observed as oligonucleotides i.e. having 2-9 pairs of nucleotides.
DNA POLYMERASE: A DNA polymerase could be a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphate. These enzymes are essential for DNA replication and typically add groups to make two identical DNA duplicates from one original DNA duplication.
HELICASE: It has the first function that is the separation of the DNA strands.in a eukaryote, it is called helicase but in a prokaryote, it is generally known as gyrase.

Note: In general all joining function in the DNA replication are done by the only one enzyme i.e. DNA ligase that’s why in molecular biology it is called as a trading name i.e. molecular glove.