Biotechnological techniques can help to diagnose the pathogen much before the symptoms of the disease appear in the patient. Suggest any two such techniques.
Answers
Answer:
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Explanation:
The Lesson
Part I: Using Biotechnology to Detect Infectious Disease (45-minute period)
1. Infectious diseases pose a threat to humans because they can pass quickly from person to person and affect a large number of people in a very short time. Influenza, or "the flu," is an infectious disease. You may have heard about avian and swine flus in the news. With the growing fear of bioterrorism and a pandemic flu, scientists are using biotechnology to develop new diagnostic tools for rapid and sensitive detection of pathogens. Biotechnology is used extensively in the study of emerging infectious diseases. To begin this lesson, show students the Genetically Engineering the Avian Flu QuickTime Video.
Note to teacher: Before showing the video, you can explain in more detail the mechanism flu viruses use to transfer their genetic information to host cells. Hemagglutinin ("H") and neuraminidase ("N") are proteins produced inside an avian flu virus particle. Hemagglutinin helps the virus gain access to a host cell. Once inside, the virus releases strands of RNA that contain the virus’s genetic material. The RNA hijacks the host cell’s nucleus, causing the host cell to manufacture viral proteins. These proteins then assemble new virus particles. Once the new virus copies are complete, neuraminidase frees them from the host cell. New virus particles may now spread infection in this same manner to other host cells.
2. In groups of four, have students discuss some of the consequences and concerns expressed in the video. Tell them they have 10 minutes to confer and should be ready to be called on to contribute to a class discussion.
Have the groups discuss the following:
What part of Dr. Tumpey's experiment is considered "genetic engineering"?
Why might Dr. Tumpey's "virus engineering" be considered controversial?
What are the potential benefits of Dr. Tumpey's "virus engineering" approach?
Identify a challenge scientists might face in developing vaccines to eradicate viruses such as the flu or HIV.
Do you think this challenge can be or will be overcome? Why or why not?
Next, lead a class discussion of the group discussions.
3. Extension Activity: For homework, ask students to go online and find other diseases that are caused by viruses. Students can fill out a 3-by-5-inch card with five facts about the viral disease they researched. Post the viral fact cards in the classroom.
Part II: Using Biotechnology to Detect Inherited Disease (45-minute period)
4. Disease does not only occur through infection. Inherited genes that reside in chromosomes and determine how proteins are formed in the body may be faulty or otherwise damaged. Genes code for the production of proteins in all living things. Changes that occur naturally in our genes are called mutations. While mutations are responsible for the genetic variation that makes living things different from one another, some mutations may produce defective proteins that cause disease. The tools and techniques researchers use to hunt down disease-causing genes change with a deepening understanding of genomes and with integration of new technologies.
Have students view A Family Disease QuickTime Video. This compelling story demonstrates the detective work scientists use to recognize a gene linked with breast cancer. Then show them Genetic Therapy and Breast Tumors QuickTime Video.
Lead a class discussion of how the dark bands on the PCR gel photo in the second video are the result of making millions of copies of a mutant gene in an individual. A band's intensity reflects the average gene copy number per cell. The highlighted bands on this gel photo show an abundance of oncogenes—genes that dispose normal cells to change into cancerous tumor cells. This may lead to a higher-than-normal expression of the protein that it encodes, which would indicate increased susceptibility for breast cancer. You can project the PCR Photo JPEG Image.
5. Then, ask students to view the Polymerase Chain Reaction Flash Interactive, which includes an animated sequence that demonstrates this important technique. While the animation features DNA from a plant source, it's important to note that the PCR process is the same regardless of the source of DNA, be it plant, human, bacteria, or other organism. Lead a summary discussion of how PCR is an automated DNA replication technique, in which small sections of the genome are recognized and copied over and over again. This provides enough of the target DNA sample to work with in the lab. Give each student the PCR Amplification Graph PDF Document, which reinforces the idea that PCR can amplify a specific DNA sequence more than a billion times in a matter of hours.
6. Extension Activity: For homework, ask students to go online and find examples (news articles) of other uses for PCR technology in DNA fingerprinting (genetic recognition) of humans, plants, or animals.