In: Biology
Which statement about DNA replication in eukaryotes is true?
Group of answer choices
Nucleotides are added from beginning to end of one strand, from 5' to 3', and then to the other strand.
Errors that occur during DNA replication are repaired by DNA polymerase.
DNA helicase adds nucleotides with complementary bases to the strand of DNA that is being synthesized.
DNA replication only occurs in somatic cells.
Nucleotides are added to the 5' end of the growing DNA strand.
DNA replication in eukaryotes involves formation of complementary strands of DNA by DNA polymerase. In eukaryotes, there are different polymerases involved in replication. These are alpha, beta, delta, epsilon, zeta, gamma, theta etc. The DNA polymerases delta and epsilon have 3’ to 5’ activity. Thus, they can carry out proof reading activity in order to correct errors during DNA replication. Thus, they can remove the incorrect base that is added during replication. These polymerases can also carry out nucleotide excision repair, base excision repair, mismatch repair and double stranded break repair, all of which are DNA repair processes. Thus, eukaryotic DNA polymerases can fix errors in DNA replication.
The replication of both DNA strands- leading and lagging strand occurs simultaneously and not one after the other. Direction of DNA replication is 5’ to 3’. Nucleotides are added to the 3’ end of growing strand as DNA polymerase requires as free 3’-OH group to add nucleotides. DNA replication occurs both in somatic and germ cells. However, only germ cells (sperm and egg) undergo meiosis. Somatic cells undergo mitosis. DNA helicase is involved in unwinding of DNA strand during replication.
Right choice: Errors that occur during DNA replication are repaired by DNA polymerase.