you join a lab studying DNA replication in bacteria. the bacteria that you are s
ID: 13139 • Letter: Y
Question
you join a lab studying DNA replication in bacteria. the bacteria that you are studying has a circular chromosome and a single origin of replication.a)the student working next to you in lab says, I will bet that if bacteria didnt make Okazaki fragments, they could still replicate their DNA. it would just take them a little bit longer.is this student right? breifly explain.
b)the student decided to test her idea by using a bacterial strain that has a temperature-sensitive mutation in the primase enzyme (since primase synthesize the most 5' end of all Okazaki fragment),will examining replication in a bacterial strain where you can inactivate the primase enzyme allowe the student to test this idea? explain briefly.
Explanation / Answer
a. The student is wrong. The DNA helix has two strands. One strand is 5'-3' and the other strand is 3'-5'. As replication occurs only from 5'-3' direction, only the 3'-5' strand can be directly replicated. The 5'-3' strand can be replicated only in the form of Okazaki fragments. This is accomplished by synthesizing many primers for this strand. The other strand has only one primer. Later, the primers are removed and filled in with DNA nucleotides. Hence, if there was no synthesis of Okazaki fragments, only one strand of the DNA would be replicated. -------------------------------------------------- b. The idea will not work out as both strands need primers. The leading strand needs one primer while the lagging strand needs many primers. Hence, if a bacterium has a temperature sensitive mutation in the primase enzyme, replication will not occur in the bacterium. As the primase is needed for both strands, both strands cannot undergo replication.Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.