Why does it appear that each origin can only be activated once per cell cycle?
A)Mcm proteins are displaced from the DNA after replication and cannot reassociate with a replication origin that has already fired.
B)The ORC is denatured after replication and cannot return to the DNA.
C)The DNA becomes naked until the next round of cell division.
D)Mcm proteins reassociate with DNA immediately and prevent further replication from that DNA.
E)Mcm proteins bind to other proteins in the cytoplasm; together they actively inhibit further replication.

Question

Why does it appear that each origin can only be activated once per cell cycle?
A)Mcm proteins are displaced from the DNA after replication and cannot reassociate with a replication origin that has already fired.
B)The ORC is denatured after replication and cannot return to the DNA.
C)The DNA becomes naked until the next round of cell division.
D)Mcm proteins reassociate with DNA immediately and prevent further replication from that DNA.
E)Mcm proteins bind to other proteins in the cytoplasm; together they actively inhibit further replication.

Quizplus · Accepted Answer

Mcm proteins are part of the pre-replication complex that assembles at origins of replication. However, once replication is initiated, the Mcm proteins are displaced from the DNA and cannot reassociate with a previously fired origin. This prevents multiple rounds of replication initiation from the same origin in a single cell cycle.

Why Does It Appear That Each Origin Can Only Be