Consider the following diagrams representing three different DNA molecules. Mole
ID: 37709 • Letter: C
Question
Consider the following diagrams representing three different DNA molecules. Molecule (a) is single-stranded, while the other two (b and c) are double-stranded
a. 5'-------------------------------------------3'
b. 3'--------------------------5
5'------------------------------------------------------3'
c. 5'--------------------------3'
3'------------------------------------------------------5-
Assuming that DNA polymerase is the only enzyme present and that there is no additional DNA, state whether each of these molecules can serve as a substrate for DNA synthesis. Give reasons as to why or why not?
Explanation / Answer
a) since its a single strand of DNA it can initiate replication it will not need helicase to unwind double strand nor it ll need gyrase to relieve strain of uwinding. DNA will replicate.
b) and c) they are double stranded DNA molecule. they have 3' OH end available for initiation of replication. but, the enzymes required for unwinding and relieving strain as entioned above are not present. also, ssb proteins which keep strands in single strand unwound position are not there. ligase to seal nicks in laggin strand okazaki fragemtns is not there. thus, b and c) can not initiate DNA synthesis.