#Question id: 3827
#Unit 3. Fundamental Processes
It takes about the same amount of time for eukaryotic chromosomes to be replicated in vivo as it does for E. coli. Why is this true?
#Question id: 3828
#Unit 3. Fundamental Processes
Why does E. coli need both DNA polymerase III and DNA polymerase I?
#Question id: 3829
#Unit 3. Fundamental Processes
Why is only one copy of DNA made per cell division cycle in eukaryotes despite the presence of multiple origins of replication?
#Question id: 3830
#Unit 3. Fundamental Processes
Why is DNA damage in skin cells from exposure to excessive UV light not completely reversed by photoreactivation?
#Question id: 3831
#Unit 3. Fundamental Processes
State whether the following statements is true/false regarding DNA replication.
1. In E. coli replication begins at the origin of replication and proceeds in one direction until the entire circular DNA molecule has been copied.
2. The chromosome of the fruit fly (D. melanogaster) is about twice as large as the E. coli chromosome.
3. Prokaryotic DNA replication occurs in two steps. First, ATP provides a phosphate to the growing DNA chain. This is followed by addition of a nucleoside.
4. DNA polymerase III is the largest DNA polymerase in E. coli.
5. The β subunits of E. coli DNA polymerase form a sliding clamp that surrounds the DNA strands at the replication fork.
#Question id: 3832
#Unit 3. Fundamental Processes
You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). Which two classes of DNA do these different samples represent?