Download Bio 313 worksheet 7 - Iowa State University

BIO 313 SI
WORKSHEET 7
Leader:
Course:
Instructor:
Supplemental Instruction
Date:
Iowa State University
1. (#18 from book) Draw a pair of homologous chromosomes from these cells (grown in
15
N medium before being placed in 14N medium) at the following stages showing the two
strands of DNA molecules found in the chromosomes, Use labels to represent 14N and
15
N.
a. Cells in G1, before switching to medium with 14N
b. Cells in G2, after switching to medium with 14N
c. Cells in anaphase of mitosis, after switching to medium with 14N
d. Cells in metaphase I of meiosis, after switching to medium with 14N
e. Cells in anaphase II of meiosis, after switching to medium with 14N
2. How does initiation occur?
3. What role does DNA Helicase perform?
4. What does DNA Gyrase (a type of Topoisomerase) do?
5. What does DNA polymerase III do? What is required for this enzyme to start?
6. Elongation at the replication fork requires 5 basic components. What are they?
7. Primers are synthesized where on the lagging strand?
A. Only at the 5’ end of the newly synthesized strand
B. Only at the 3’ end of the newly synthesized strand
C. At the beginning of every Okazaki fragment
D. At multiple places within an Okazaki fragment
1060 Hixson-Lied Student Success Center  515-294-6624  [email protected]  http://www.si.iastate.edu
8. What enzyme adds the RNA primers?
9. What enzyme removes and replaces primers with dNTP?
10. How are Okazaki fragment ends joined together? What type of bond is formed?
11. How would DNA replication be affected in a bacterial cell that is lacking DNA gyrase?
12. What are the two basic cell types? Give two examples of how they differ.
13. List several characteristics that eubacteria and archaea have in common and that
distinguish them from eukaryotes.
14. How does bacterial DNA differ from eukaryotic DNA?