4-6-Learning objectives

Question 1

Identify the four basic steps of genetic engineering.

Answer 1

Step 1 - cutting DNA: DNA containing the gene of interest is isolated from the organism and treated with a restriction enzyme. The vector (a DNA “agent” used to carry the gene of interest) is cut with the same restriction enzyme.

Step 2 - making recombinant DNA: The DNA fragments containing the gene of interest are combined with the DNA fragments from the vector. The DNA fragments are linked into a recombinant DNA molecule with the help of DNA ligase.

Step 3 - Cloning: Vectors carrying the gene of interest are inserted into bacteria, where they replicate.

Step 4 - Screening and protein production: Cells that have received the particular gene of interest are separated from cells that have not. The cells containing the gene of interest can then transcribe and translate the gene to make the protein of interest.

Question 2

Describe the importance of vaccines

Answer 2

Many viral diseases such as polio and smallpox cannot be treated effectively by existing drugs. Vaccines are important because they are used to fight such diseases.

Vaccines contain all or part of a harmless version of the pathogen (the disease-causing microorganism). When the vaccine is injected into the body, the body’s immune system produces defensive proteins (antibodies) against the pathogen’s proteins. In the future, when the infectious version of the pathogen enters the body, the antibodies will already be there to fight the pathogen before it causes a disease.

Question 3

Summarize how drugs produced by genetic engineering are being used.

Answer 3

Genetic engineering can produce large quantities of protein drugs such as insulin and human growth hormone that cannot be efficiently synthesized chemically or isolated from animal organs in pure and large quantities. Genetic engineering made such drugs available to the human population at large and have saved many lives.

Some genetically engineered drugs and their uses are:

• Human growth hormone for the treatment of growth defects
• Insulin for the treatment of diabetes
• Growth factors for the treatment of burns and ulcers
• Erythropoetin for the treatment of anemia
• Interferons for the treatment of viral infections and cancer
• Taxol for the treatment of ovarian cancer

Question 4

Explain two uses for DNA fingerprints

Answer 4

Two uses of DNA fingerprints are:

(1) identify a crime suspect from blood or semen samples
(2) determine the genetic make up of long-dead individuals or extinct organisms

Question 5

Describe three ways that genetic engineering has been used to improve crops.

Answer 5

Genetic engineering has been used to improve crops by introducing genes into the plants that:

(1) make them resistant to herbicides, pests, and/or diseases
(2) increase their tolerance to heat, cold, and/or drought
(3) make them more nutritious (e.g., rice rich in vitamin A)