A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? Okazaki fragments nucleotides DNA ligase primase DNA polymerase

Answer: DNA ligase

Explanation: During replication, two new strands are synthesized: The leading strand and the lagging strand.

The leading strand is synthesized in a continuous manner while the lagging strand is synthesized discontinuously in short segments called the Okazaki fragments. The leading strand is the strand whose 5'->3' synthesis is in the direction of the fork movement while the lagging strand is the strand whose 5'->3' synthesis is in the direction opposite to the fork movement. The Okazaki fragments are joined by an enzyme known as DNA ligase. DNA ligase is one of the enzymes involved in DNA replication which catalyzes the joining of two or more polynucleotide chains.

The correct answer is DNA ligase.

Explanation:

DNA Ligase is an enzyme with links 2 strands of DNA by creating a bond between the phosphate group of 1 strand and deoxyribose group of the other strand of DNA.

In cells, it is used to join the Okazaki fragments together which are formed on the lagging strand during the process of DNA replication.

Okazaki fragments are tiny pieces of DNA nucleotide which are formed in a discontinued manner but latter they are joined by DNA ligase enzyme.