12.7 - 12.9

Question 1

Note 1 —-»

Answer 1

Two products made using recombinant cells are human insulin and human growth hormone. Insulin, normally secreted by the pancreas, is a hormone that helps regulate the levels of glucose in the blood. Insulin must be injected daily by people with type I diabetes. Before 1982, the main sources of this hormone were slaughtered pigs and cattle. Although insulin extracted from these animals is chemically similar, it is not identical to human insulin and can therefore cause allergic reactions in some people. Genetic engineering has largely solved this problem by developing bacteria that synthesize and secrete the human form of insulin.

Question 2

Note 2 —-»

Answer 2

Treatment with human growth hormone (HGH) is a boon to children born with a form of dwarfism caused by inadequate amounts of this hormone. Because growth hormones from other animals are not effective in humans, children with HGH deficiency historically have had to rely on scarce and expensive supplies extracted from human cadavers. In 1985, however, molecular biologists made an artificial gene for HGH. Using this lab-made gene, they were able to create recombinant E. coli that produce HGH. Human growth hormone from recombinant bacteria is now widely used.

Question 3

Note 3 —-»

Answer 3

DNA technology can pinpoint microorganisms responsible for disease outbreaks. For example, DNA analysis can help track down and identify elusive viruses, such as HIV, which causes AIDS. The Centers for Disease Control and Prevention regularly uses DNA technology to identify the precise strain of bacteria that is causing a food poisoning outbreak, allowing officials to announce and implement more stringent food safety measures.

Question 4

Vaccine

Answer 4

A harmless variant or derivative of a pathogen used to stimulate a host organism’s immune system to mount a long-term adaptive response against the pathogen.

Question 5

Note 4 —-»

Answer 5

DNA technology is helping medical researchers develop vaccines. A vaccine is a harmless variant (mutant) or derivative of a pathogen—usually, a bacterium or virus—that is used to stimulate the immune system to mount a lasting defense against that pathogen, thereby preventing disease.

Question 6

If insulin and human growth hormone are both natural products, why use genetic engineering to make them?

Answer 6

DNA technology can provide these drugs in much larger quantities than can be naturally obtained.

Question 7

Genetically Modified Organisms (GMOs)

Answer 7

Any organism whose genetic material has been altered using genetic engineering techniques.

Question 8

Transgenic Organism

Answer 8

An organism that contains genes from another species.

Question 9

What are the odds that you consumed a transgenic plant or animal today?

Answer 9

If you live in the United States, it is highly likely that you consumed a transgenic plant, but highly unlikely that you consumed a transgenic animal.

Question 10

Note 5 —»

Answer 10

Advocates of a cautious approach toward GMO crops fear that transgenic plants might pass their new genes to related species in nearby wild areas, disturbing the composition of the natural ecosystem. Critics of GMO crops can point to several studies that do indeed show unintended gene transfer from engineered crops to nearby wild relatives. But GMO advocates counter that no lasting or detrimental effects from such transfers have been demonstrated and that some GMOs (such as bacteria engineered to break down oil spills) can actively help the environment.

Question 11

Why is it often necessary to run both human and animal studies to learn about human health?

Answer 11

Animal diets and lifestyles can be closely controlled, but the results may not apply directly to humans.