Back
Problem 1
Imagine you have found a small quantity of DNA. Fill in the following diagram, which outlines a series of DNA technology experiments you could perform to study this DNA.
<IMAGE>
a.
b.
c.
d.
e.
Problem 2
Which of the following would be considered a transgenic organism?
a. A bacterium that has received genes via conjugation
b. A human given a corrected human blood-clotting gene
c. A fern grown in cell culture from a single fern root cell
d. A rat with rabbit hemoglobin genes
Problem 3
The DNA profiles used as evidence in a murder trial look something like supermarket bar codes. The pattern of bars in a DNA profile shows
a. The order of bases in a particular gene.
b. The presence of various-sized fragments of DNA.
c. The presence of dominant or recessive alleles for particular traits.
d. The order of genes along particular chromosomes.
Problem 4
A paleontologist has recovered a tiny bit of organic material from the 400-year-old preserved skin of an extinct dodo. She would like to compare DNA from the sample with DNA from living birds. Which of the following would be most useful for increasing the amount of DNA available for testing?
a. Restriction fragment analysis
b. Polymerase chain reaction
c. Molecular probe analysis
d. Electrophoresis
Problem 5
How many genes are there in a human sperm cell?
a. 23
b. 46
c. About 21,000
d. about 3 billion
Problem 6
When a typical restriction enzyme cuts a DNA molecule, the cuts are uneven, giving the DNA fragments single-stranded ends. These ends are useful in recombinant DNA work because
a. They enable a cell to recognize fragments produced by the enzyme.
b. They serve as starting points for DNA replication.
c. The fragments will bond to other fragments with complementary ends.
d. They enable researchers to use the fragments as molecular probes.
- Why does DNA profiling rely on comparing specific genetic markers rather than the entire genome?
Problem 7
- Recombinant DNA techniques are used to custom-build bacteria for two main purposes: to obtain multiple copies of certain genes and to obtain useful proteins produced by certain genes. Give an example of each of these applications in medicine and agriculture.
Problem 8
- A biochemist hopes to find a gene in human cells that codes for an important blood-clotting protein. She knows that the nucleotide sequence of a small part of the blood-clotting gene is CTGGACTGACA. Briefly outline a possible method she might use to isolate the desired gene.
Problem 9
Problem 10
A biologist isolated a gene from a human cell, inserted it into a plasmid, and inserted the plasmid into a bacterium. The bacterium made a new protein, but it was nothing like the protein normally produced in a human cell. Why? (Explain your answer.)
a. The bacterium had undergone transformation.
b. The gene did not have sticky ends.
c. The human gene contained introns.
d. The gene was not synthesized from scratch.
Problem 11
Explain how you might engineer E. coli to produce human growth hormone (HGH) using the following: E. coli containing a plasmid, DNA carrying the gene for HGH, DNA ligase, a restriction enzyme, equipment for manipulating and growing bacteria, a method for extracting and purifying the hormone, and an appropriate DNA probe. (Assume that the human HGH gene lacks introns.)
- What is left for genetic researchers to do now that the Human Genome Project has determined nearly complete nucleotide sequences for all of the human chromosomes? Explain.
Problem 12
- Today, it is fairly easy to make transgenic plants and animals. What are some important safety and ethical issues raised by this use of recombinant DNA technology? What are some of the possible dangers of introducing genetically engineered organisms into the environment? What are some reasons for and against leaving decisions in these areas to scientists? To business owners and executives? What are some reasons for and against more public involvement? How might these decisions affect you? How do you think these decisions should be made?
Problem 13
- In the not-too-distant future, gene therapy may be an option for the treatment and cure of some inherited disorders. What do you think are the most serious ethical issues that must be dealt with before human gene therapy is used on a large scale? Why do you think these issues are important?
Problem 14
Problem 15a
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. For example, should employers or potential employers have access to such information?
Problem 15b
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. Should the information be available to insurance companies? Why or why not?
Problem 15c
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. Is there any reason for the government to keep genetic files?
Problem 15d
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. Is there any obligation to warn relatives who might share a defective gene?
Problem 15e
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. Might some people avoid being tested for fear of being labeled genetic outcasts?
Problem 15f
The possibility of extensive genetic testing raises questions about how personal genetic information should be used. Or might they be compelled to be tested against their wishes? Can you think of other reasons to proceed with caution?
Problem 15g
The possibility of extensive genetic testing raises questions about how personal genetic information should be used.
Problem 16
Scientists investigate hypotheses using a variety of methods, depending on the circumstances behind the research. Human nutrition studies (such as those studying whether GMO foods have any health effects) are particularly problematic. Can you design a hypothetical human nutrition study to test whether GMO corn is less healthy than traditional corn? Can you identify real-world problems that may interfere with your design and confound your results?
Problem 18
The fruits of wild species of tomato are tiny compared with the giant beefsteak tomatoes available today. This difference in fruit size is almost entirely due to the larger number of cells in the domesticated fruits. Plant biologists have recently discovered genes that are responsible for controlling cell division in tomatoes.
Why would such a discovery be important to producers of other kinds of fruits and vegetables?
To the study of human development and disease?
To our basic understanding of biology?