AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA REPLICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, 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
DNA ligase
B
nucleotides
C
DNA polymerase III
D
Okazaki fragments
Explanation: 

Detailed explanation-1: -When she adds some DNA to the mixture, 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? DNA polymerase.

Detailed explanation-2: -What has she probably left out of the mixture? The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine.

Detailed explanation-3: -Correct answer: Explanation: The only false statement is that DNA replication of the lagging strand is continuous. The leading strand features continuous replication while the lagging stand is initially made up of discontinuous Okazaki fragments, which are sealed later by ligase.

Detailed explanation-4: -Abstract. DNA polymerase III holoenzyme (Pol III HE) is an enzyme that catalyzes elongation of DNA chains during bacterial chromosomal DNA replication.

Detailed explanation-5: -DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied.

There is 1 question to complete.