Concept Questions

Take some time to write answers to these questions. If you can answer them, you have a good grasp of the material!

1. Define genetic engineering and biotechnology, and summarize the important purposes of these fields. Review the use of the terms genome, chromosome, gene, DNA, and RNA from chapter 9.

2. Describe the processes involved in denaturing and renaturing of DNA. What is useful about this procedure? Why is it necessary to denature the DNA in the Southern blot test? How would the Southern blot be used with PCR?

3. Given the shorthand for the following restriction endonucleases: Arthrobacter luteus I; Providencia stuartii I; Bacillus amyloliquefaciens H I What kind of cut will HaeIII make? Using nucleotide letters, show how a piece of DNA can be cut to circularize it. What are restriction length polymorphisms, and how are they used?

4. Explain how electrophoresis works and the general way that DNA is sized. Estimate the size of the DNA fragment in base pairs in the first lane of the gel in figure 10.4. Define oligonucleotides, explain how they are formed, and give three uses for them.

5. Briefly describe the functions of DNA synthesizers and sequencers. How would you make a copy of DNA from an mRNA transcript? Show how this process would look, using base notation. What is this DNA called? Why would it be an advantage to synthesize eucaryotic genes this way?

6. Explain the meaning of this shorthand to represent the polymerase chain reaction: Describe the effects of temperature change in PCR. Exactly what are the functions of the primer and Taq polymerase? Explain why the PCR is unlikely to amplify contaminating bacterial DNA in a sample of human DNA.

7. What characteristics of plasmids and bacteriophages make them good cloning vectors? Name several types of vectors, and explain what benefits they have. List the types of genes that they can contain.

8. Describe the principles behind recombinant DNA technology. Outline the main steps in cloning a gene. Once cloned, how can this gene be used? Characterize several ways that recombinant DNA technology can be used.

9. What characteristics of bacteria make them good cloning hosts? What is one way to determine whether a bacterial culture has received a recombinant plasmid?

10. What is transfection, and what are transgenic organisms? Explain how Agrobacterium is used to transfect plants. Describe a method for transfecting animals. Summarize some of the uses for transgenic plants and animals.

11. What is the main difference between ex vivo and in vivo gene therapy? Does the virus vector used in gene therapy replicate itself in the host cell? Why would this not be a good idea? What are some of the main problems with gene therapy?

12. Describe the molecular mechanisms by which a DNA antisense molecule could work as a genetic medicine. Do the same for triplex DNA. Are the therapies permanent? Why or why not?

13. What is a gene map? Show by a diagram how chromosomal, physical, and sequence maps are different? Which organisms are being mapped, and what uses will these maps perform? Why is the human genome map going to require 20 years? What are some possible effects of knowing the genetic map of humans?

14. Describe what a DNA fingerprint is and why and how restriction fragments can be used to form a unique DNA pattern. Discuss briefly how DNA fingerprinting is being used routinely by biomedicine, the law, the military, and human biology.

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