Answer:
b. During replication there is both a leading strand and a lagging strand
.
c. Each replication bubble has two replication forks.
Explanation:
Eukaryotic chromosomes have multiple origins of replication to replicate the long chromosomes at a higher rate.
The two DNA strands have opposite polarity, that is, 5' end of the one DNA strand is present opposite to the 3' end of the other DNA strand. DNA replication occurs only in 5' to 3' direction and the direction of the movement of the replication fork is also 5' to 3' direction.
To allow the DNA replication in 5' to 3' direction on both strands, one strand is replicated discontinuously in the direction opposite to the movement of the replication fork.
The discontinuously replicated strand is lagging strand while the other one is the leading strand.
DNA replication in eukaryotes occurs bidirectionally as two replication forks are formed at each replication bubble, one at each end of the replication bubble.
The presence of multiple origins of replication and the bidirectional process allows the replication of large eukaryotic DNA at a considerable fast speed.
