Comprehension Questions

Section 19.1

Question 19.1

List some of the effects and practical applications of molecular genetic analyses.

Section 19.2

Question 19.2

What feature is commonly seen in the sequences recognized by type II restriction enzymes?

Question 19.3

What normal role do restriction enzymes play in bacteria? How do bacteria protect their own DNA from the action of restriction enzymes?

Question 19.4

Explain how gel electrophoresis is used to separate DNA fragments of different lengths.

Question 19.5

After DNA fragments have been separated by gel electrophoresis, how can they be visualized?

Question 19.6

What is the purpose of Southern blotting? How is it carried out?

Question 19.7

Give three important characteristics of cloning vectors.

Question 19.8

Briefly describe two different methods for inserting foreign DNA into plasmids, giving the strengths and weaknesses of each method.

Question 19.9

Briefly explain how an antibiotic-resistance gene and the lacZ gene can be used to determine which cells contain a particular plasmid.

Question 19.10

Briefly explain how the polymerase chain reaction is used to amplify a specific DNA sequence. What are some of the limitations of PCR?

Question 19.11

What is real-time PCR?

Section 19.3

Question 19.12

How does a genomic library differ from a cDNA library?

Question 19.13

How are probes used to screen DNA libraries? Explain how a synthetic probe can be prepared when the protein product of a gene is known.

Question 19.14

Briefly explain in situ hybridization, giving some applications of this technique.

Question 19.15

Briefly explain how a gene can be isolated through positional cloning.

Question 19.16

Explain how chromosome walking can be used to find a gene.

Section 19.4

Question 19.17

What is the purpose of the dideoxynucleoside triphosphate in the dideoxy sequencing reaction?

Question 19.18

What is DNA fingerprinting? What types of sequences are examined in DNA fingerprinting?

Section 19.5

Question 19.19

How does a reverse genetics approach differ from a forward genetics approach?

Question 19.20

Briefly explain how site-directed mutagenesis is carried out.

Question 19.21

What are knockout mice, how are they produced, and for what are they used?

Question 19.22

How is RNA interference used in the analysis of gene function?

Section 19.6

Question 19.23

What is gene therapy?

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