BIOL260 Name_________________________
Homework #5
1. For a quick review of DNA, list four general characteristics related to the chemical structure of DNA.
2. Draw your own version of the chemical structure of DNA, include the key components. Be sure to include labels!
3. What is the role of the following enzymes in DNA replication?
DNA Polymerase
DNA ligase
Primase
Helicase
4. If you have a strand of DNA with the following sequence:
a. What is the complementary strand of DNA?
3’ G T T A C A A T A G C G T G G C A C C T A C T T G 5’
. If this DNA is transcribed, what is the co
esponding mRNA?
3’ G T T A C A A T A G C G T G G C A C C T A C T T G 5’
c. If the mRNA is translated, what is the order of amino acids found in this mRNA which code for a protein?
5. What is the definition of an operon?
6. You have E. coli growing in a flask with both glucose and lactose. After 12 hours of growth the following growth curve is generated.
a. Is this curve reflective of a typical growth curve? Explain why or why not.
. Next to the growth curve, draw what the curve would look like if the cells were growing in a
oth with only glucose.
7. The genes for metabolizing lactose in bacteria are located on the lactose operon. Draw the operon and label all the regulatory and gene coding regions.
8. If an E. coli cell is growing in a
oth with a high concentration of glucose and lactose, is the lactose operon “on”? Explain.
9. What is quorum sensing?
10. How does quorum sensing contribute to the ability of Vi
io cholerae to cause disease? (Review the Focus on a Case 7.1 on p. 192)