Bio 99 Midterm 1 Lec: 6

Control of cell cycle:

CDKactivation by cyclin

Pre-replication Complex (preRC) formation is _________

preRC forms in __ phase

RC activated in __ phase

Why must replication be regulated?

DNA in the cell is _______

_________ alter the degree of supercoiling

After the unbroken strand passes through the nick in the DNA to relieve supercoiling, how is the nicked DNA strand made intact again?
A. DNA ligase seals the nick
B. The free 3’OH group on the nicked nucleotide attacks the topoisomerase-nucleotide bond
C. Topoisomerase uses ATP to reverse the strand break it created
D. The free 5’phosphate group on the nicked nucleotide attacks the topoisomerase-nucleotide bond

End Replication Problem
How do you replicate the end of DNA?

The End Replication Problem occurs because:
A. There is often a nucleotide shortage and the ends are replicated last
B. The RNA primer regions at the end of the DNA cannot be replaced with DNA
C. DNA polymerase cannot make the final Okazaki fragment
D. DNA ligase is unable to function at the end of a piece of DNA

Shortening of telomeric DNA during cell proliferation

Protection of chromosme ends

Structure of the t-loop