COMPREHENSION QUESTIONS

Section 12.1

Question 1

1.Why is gene regulation important for bacterial cells?

Question 2

2.Name six different levels at which gene expression might be controlled.

Section 12.2

Question 3

3.Draw a picture illustrating the general structure of an operon and identify its parts.

Question 4

4.What is the difference between positive and negative control? What is the difference between inducible and repressible operons?

Question 5

5.Briefly describe the lac operon and how it controls the metabolism of lactose.

Question 6

6.What is catabolite repression? How does it allow a bacterial cell to use glucose in preference to other sugars?

Section 12.3

Question 7

7.What changes take place in chromatin structure and what role do these changes play in eukaryotic gene regulation?

Question 8

8.What is the histone code?

Question 9

9.Briefly explain how transcriptional activator and repressor proteins affect the level of transcription of eukaryotic genes.

Question 10

10.What is an enhancer? How does it affect the transcription of distant genes?

Question 11

11.What role does mRNA stability play in gene regulation? What controls mRNA stability in eukaryotic cells?

Question 12

12.Briefly list some of the ways in which siRNAs and miRNAs regulate genes.

Question 13

13.How does bacterial gene regulation differ from eukaryotic gene regulation? How are they similar?

Section 12.4

Question 14

14.What are epigenetic effects? How do they differ from other genetic traits?

Question 15

15.What types of changes are thought to be responsible for epigenetic traits?

Question 16

16.How are patterns of DNA methylation maintained across cell divisions?

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