12: Chapter Replication Part 2 Bacterial Replication: What are the four steps of bacterial replication? 1. 2. 3. 4. Where does the initiator protein bind to start the replication process? What are the three unwinding proteins and what is the specific purpose of each? 1. 2. 3. The enzyme __________________________ catalyzes DNA synthesis using the dNTP substrates. However, it needs a 3'OH to begin synthesis so the enzyme _________________ (which does not need a 3'OH) lays down a primer. How long is the primer and what is it made out of?
Bacteria have five different types of DNA polymerases. Which polymerase is used to synthesize the new DNA strand? _____________ Which polymerase is used to remove RNA primers? _____________________ Which polymerases are used for DNA repair? __________________________ Place a check mark next to the capabilities that each of the DNA polymerases posses. 5' 3' polymerase 5' 3' 3' 5' activity exonuclease exonuclease activity activity DNA polymerase I DNA polymerase III DNA polymerase II ____________________ is an enzyme that connects discontinuous fragments, not by adding new nucleotides, but by creating a phosphodiester bond between the two fragments.
The ____________ protein binds to termination sequences and ends replication by blocking the helicase activity. How accurate is replication? In other words, how many mistakes are made?
What three processes contribute to this accuracy? (I do not think that you will need to know much about these right now since there is a whole chapter dedicated to them later) 1. 2. 3. Eukaryotic Replication The initiator proteins cannot bind to the origin of replication in eukaryotes until the _______________________________ binds first. Eukaryotes have many different DNA polymerases. You will need to know Which two: polymerase synthesizes the new DNA strand? ____________________ Which polymerase has primase activity? ______________________________ Why do linear chromosome ends (called telomeres) gradually get shorter after each replication cycle?
The enzyme ___________________ prevents the shortening of chromosome ends and is only active in ______________ cells and ________________ cells. True or False: Bacterial DNA also gets shorter after each replication round. The telomerase enzyme is composed of what two elements? 1. 2. Be able to explain how the telomerase enzyme lengthens the ends of the chromosome.
Questions from the back of the book: 19. A circular molecule of DNA contains 1 million base pairs. If the rate of DNA synthesis at a replication fork is 100,000 nucleotides per minute, how much time will theta replication require to replicate the molecule? How long will replication take by rolling-circle replication? (Ignore replication of the displaced strand in rolling-circle replication).
20. A bacterium synthesizes DNA at each replication fork at a rate of 1000 nucleotides per second. If this bacterium completely replicates its circular chromosome by theta replication in 30 minutes, how many base pairs of DNA will its chromosome contain?
22. What would be the effect on DNA replication of mutations that destroyed each of the following activities in DNA polymerase I? a. 3' 5' exonuclease activity b. 5' 3' exonuclease activity c. 5' 3' polymerase activity
24. A line of mammalian cells possesses a mutation that destroys the replication licensing factor. What would be the effect of this mutation on the cells? What would be the effect of if the cells possessed a mutation that caused the licensing factor to remain attached to origins even after replication?