Exam 10: DNA Replication and Recombination

Which protein is responsible for the initial step in unwinding the DNA helix during replication of the bacterial chromosome?

DNA strand replication begins with an RNA primer.

DNA polymerase I is thought to add nucleotides ________.

Given that the nature of DNA replication in eukaryotes is not as well understood as in prokaryotes,(a)present a description of DNA (chromosome)replication as presently viewed in eukaryotes and (b)state the differences known to exist between prokaryotic and eukaryotic DNA replication.

Assume that you were growing cells in culture and had determined the cell-cycle time to be 24 hours.You introduce ³H thymidine and prepare autoradiographs of metaphase chromosomes after 48 hours.Of the chromosomes that are labeled,you expect two classes: one class that had completed one S phase in the label,and a second class that had completed a cellular division and an additional S phase in the label.Draw the DNA (double-stranded)labeling pattern for each chromosome that you would expect to find in these two types of metaphase chromosomes.(Use a broken line {- - -} for labeled single strands of DNA and a solid line for unlabeled single strands of DNA.) (a)metaphase chromosome having replicated once in label (b)metaphase chromosome having gone through two S phases in label

Given the diagram below,assume that a G1 chromosome (left)underwent one round of replication in ³H-thymidine and the metaphase chromosome (right)had both chromatids labeled.Which of the following replicative models (conservative,dispersive,semiconservative)could be eliminated by this observation?

The discontinuous aspect of replication of DNA in vivo is caused by ________.

Describe the DNA base sequence arrangement at the end of the Tetrahymena chromosome and the resolution of DNA replication at the end of a linear DNA strand.

Given that the origin of replication is fixed in E.coli,what signals the location of the origin?

Structures located at the ends of eukaryotic chromosomes are called ________.