(3) Chapter 9: Biotechnology

What is Bacillus thuringiensis (Bt)?

A bacterium that naturally produces a toxin that kills certain insects.

What is Bt toxin?

An insecticidal protein naturally produced by Bacillus thuringiensis.

How are Bt crops created?

The Bt toxin gene is inserted into the plant's DNA so the plant produces the insecticidal protein.

What is the purpose of Bt corn and Bt cotton?

To kill insect pests that feed on the plants.

Why are Bt crops beneficial to farmers?

They reduce insect damage and decrease the need for chemical insecticides.

Does Bt toxin harm the plant itself?

No. It is produced by the plant to kill susceptible insect pests.

What genetic modification is used to extend the shelf life of tomatoes and raspberries?

An antisense gene blocks pectin degradation, slowing ripening.

Why are genetically modified tomatoes and raspberries slower to ripen?

Pectin breakdown is reduced, delaying softening and spoilage.

What advantage does delayed fruit ripening provide?

Longer shelf life during storage and transportation.

According to the professor, why do some genetically modified fruits never seem to ripen?

Their ripening process has been genetically slowed to increase shelf life.

What are Roundup Ready crops?

Genetically modified crops that are resistant to the herbicide glyphosate (Roundup).

Why were Roundup Ready crops developed?

So weeds can be killed without harming the crop.

What is glyphosate?

The herbicide used in Roundup.

How do Roundup Ready crops survive herbicide treatment?

They contain a bacterial gene that makes them resistant to glyphosate.

What genetic modification was discussed for Aedes aegypti mosquitoes?

Male mosquitoes carry a gene that causes their offspring to die.

Why are genetically engineered Aedes aegypti mosquitoes released?

To reduce mosquito populations and decrease disease transmission.

Which disease did the professor specifically associate with Aedes aegypti?

Zika virus.

Why are only male genetically modified mosquitoes released?

Male mosquitoes do not bite people and pass the lethal gene to offspring.

What is GloFish?

Fluorescent fish created by inserting genes for fluorescent proteins from marine organisms.

Why were GloFish originally developed?

As an example of genetic engineering and fluorescent protein expression.

What are Atlantic salmon genetically modified to do?

Grow faster than normal salmon.

What genetic changes allow Atlantic salmon to grow faster?

Genes from Chinook salmon and regulatory DNA from another fish increase growth.

Why are genetically modified salmon commercially useful?

They reach market size more quickly.

What was the professor's point about genetically modified foods?

Many foods people eat every day contain genetically modified ingredients.

Why did the professor mention a hamburger as an example?

Many ingredients in a typical hamburger meal come from genetically modified crops.

What did the professor say about genetically modified decaffeinated coffee?

Genetic engineering may remove the caffeine-producing gene instead of chemically extracting caffeine.

Why would genetically engineered decaffeinated coffee be advantageous?

It would reduce the cost and water required for traditional decaffeination.

What is cloned meat?

Meat produced from cloned animals.

Did the professor encourage students to research other genetically modified foods?

Yes. She suggested students could easily find many additional examples.

What term did the professor mention that is sometimes used in Europe for genetically modified foods?

Frankenfood.

What did the professor say about genetically modified foods in some European countries?

Some countries have banned or restricted them because of ethical and social concerns.

What are some concerns about genetically modified organisms (GMOs)?

Ethical issues, environmental effects, and potential impacts on human health.

How many serious genetic disorders did the professor say exist?

More than 15,000.

What is gene therapy?

The introduction of a normal gene into a patient to treat a genetic disorder.

What is the goal of gene therapy?

To replace or compensate for a defective gene.

Why is gene therapy considered a potential cure for genetic diseases?

It addresses the underlying genetic defect rather than only treating symptoms.

Can traditional treatments cure most genetic disorders?

No. They usually treat symptoms rather than correcting the defective gene.

What genetic disorder did David Vetter have?

Severe Combined Immunodeficiency (SCID).

What is Severe Combined Immunodeficiency (SCID)?

A genetic disorder in which patients are born with little or no functional immune system.

Why was David Vetter called the "Bubble Boy"?

He lived in a sterile environment to avoid life-threatening infections.

Why did David Vetter require complete isolation?

Without an immune system, ordinary microbes could be fatal.

How old was David Vetter when he received a bone marrow transplant?

About 11 years old.

Did David Vetter survive after his bone marrow transplant?

No. He later died from cancer.

Why did the professor discuss David Vetter?

To illustrate the limitations of early treatments before successful gene therapy.

Who was Ashanti DeSilva?

One of the first successful patients treated with gene therapy for SCID.

Why is Ashanti DeSilva important in biotechnology?

She demonstrated that gene therapy could successfully treat a genetic disease.

What was the outcome of Ashanti DeSilva's gene therapy?

She developed a functioning immune system and survived.

How was early gene therapy performed for SCID?

A healthy gene was inserted into bone marrow cells using a viral vector.

What cells were modified during early SCID gene therapy?

Bone marrow cells.

Why were bone marrow cells chosen for SCID gene therapy?

They produce immune system cells.

What type of vector was used in early gene therapy?

A modified animal virus.

Why are viral genes removed from gene therapy vectors?

To prevent the virus from causing disease.

What replaces the viral genes in a gene therapy vector?

The healthy therapeutic gene.

Did every treated cell receive the new gene during early gene therapy?

No. Only some cells incorporated the gene.

Why was early gene therapy considered successful even if only some cells received the gene?

Enough corrected cells produced a functional immune response.

What major problem did the professor describe with early gene therapy?

The inserted gene entered the DNA at unpredictable locations.

Why is random insertion of therapeutic genes dangerous?

It can disrupt important genes or activate cancer-causing genes.

What type of gene can become activated and cause cancer after random insertion?

A proto-oncogene.

What is a proto-oncogene?

A normal gene that can become cancer-causing if altered or improperly activated.

What other complication of early gene therapy did the professor mention?

Some patients developed severe allergic reactions to the viral protein coat.

Why could viral vectors trigger allergic reactions?

The immune system recognized viral proteins as foreign.

Why was early gene therapy considered unpredictable?

Scientists could not control exactly where the new gene inserted into the genome.

What is CRISPR?

A gene-editing technology that allows precise modification of DNA.

Why is CRISPR considered a major breakthrough?

It allows scientists to edit genes at specific locations instead of randomly inserting DNA.

What is another name for CRISPR technology?

Gene editing.

Who received the 2020 Nobel Prize for developing CRISPR gene editing?

Jennifer Doudna and Emmanuelle Charpentier.

Where does Jennifer Doudna work according to the professor?

The University of California, Berkeley.

Why did Jennifer Doudna and Emmanuelle Charpentier receive the Nobel Prize?

For developing CRISPR gene-editing technology.

What is the major advantage of CRISPR over older gene therapy techniques?

It edits DNA precisely at a chosen location.

Can CRISPR remove defective genes?

Yes. It can remove defective DNA and replace it with healthy DNA.

Why is CRISPR safer than early viral gene therapy?

It greatly reduces random insertion into the genome.

What did the professor say about CRISPR clinical trials?

The first approved clinical trial began in 2016 for cancer patients.

What successful CRISPR experiment did the professor mention?

Repairing the defective gene responsible for muscular dystrophy in mice.

What blood disorder did the professor mention is being treated with CRISPR research?

Sickle cell anemia.

Why did the professor describe CRISPR as promising?

It has the potential to precisely correct disease-causing mutations.

What did the professor call CRISPR technology?

A very promising technology for treating genetic diseases.