Question 1

Which of the following is a vector used to deliver genes in human gene therapy?

Accepted Answer

Adeno-associated virus (AAV) is commonly used as a vector for gene therapy because it has a low incidence of causing human disease and can efficiently deliver genetic material to target cells. Parvovirus, rabies virus, and Ebola virus are not commonly used as vectors in human gene therapy due to their pathogenicity and potential to cause harm. E. coli is not a virus and is not typically used as a vector in gene therapy.

Question 2

The defect in Canavan disease that causes the symptoms is

Accepted Answer

The defect in Canavan disease is the lack of an enzyme called aspartoacylase, which normally breaks down a substance called N-acetylaspartic acid (NAA) in the brain. The build-up of NAA results in the stripping of the lipid layer from brain neurons, leading to the symptoms of Canavan disease.

Question 3

Which of the following would provide the longest lasting treatment for adenosine deaminase (ADA)deficiency?

Accepted Answer

Supplying progenitor T cells genetically modified to carry functional ADA genes shortly after birth would provide the longest lasting treatment for ADA deficiency. This is because progenitor T cells are able to differentiate into various immune cells including T cells, B cells, and natural killer cells, which can produce ADA proteins. Therefore, this treatment can provide long-term production of ADA proteins in the patient's immune system.

Question 4

Muscle is a good target for gene therapy because

Accepted Answer

Muscle is a good target for gene therapy because it is an abundant tissue with a rich blood supply, allowing for efficient delivery of therapeutic genes to the affected area.

Question 5

A difficulty in developing gene therapy for diseases of the nervous system is that

Accepted Answer

Nerve cells (neurons) do not divide, so any genetic modification would not be naturally propagated through cell division, making it challenging to achieve widespread and lasting effects in the nervous system.

Question 6

A serious limitation of using a retrovirus as a vector for gene therapy is that

Accepted Answer

Retroviruses have the potential to insert their genetic material into the host genome, but this insertion may occur near or within a proto-oncogene, causing it to become overactive and potentially causing cancer. This is a serious limitation to retroviral vectors for gene therapy.

Question 7

Reginald receives a stem cell transplant to treat a blood cancer,multiple myeloma.His treatment is an example of

Accepted Answer

Reginald's treatment involves the use of stem cells from a donor to replace his own damaged cells. This is an example of somatic gene therapy, as it targets the cells of the body (somatic cells) rather than the reproductive cells (germline cells). Options A, B, and C involve manipulation of the genetic material in reproductive cells, whereas option E refers to a method of assisted reproductive technology and is not related to gene therapy.

Question 8

Germline gene therapy would correct a genetic defect in

Accepted Answer

Germline gene therapy targets the reproductive cells, meaning that the genetic correction is passed on to all descendants of the affected individual, correcting the defect in both the individual and their future offspring.

Question 9

Many children born with ornithine transcarbamylase deficiency (OTC)die within seventy-two hours of birth.Jesse Gelsinger was not diagnosed with OTC until he was two because _______ and therefore his symptoms were milder.

Accepted Answer

Jesse Gelsinger was not diagnosed with OTC until he was two years old because he was a mosaic, which means that not all of his cells carried the defective gene. Therefore, his symptoms were milder.

Question 10

A patient received bone marrow modified by an adeno-associated virus (AAV)carrying the human gene that encodes an enzyme her body could not make.This is an example of

Accepted Answer

This is an example of somatic gene therapy, as the modification only occurred in the patient's bone marrow cells and not in their germ cells (eggs or sperm). Protein therapy involves the administration of proteins, while germline gene therapy involves modifying the DNA in reproductive cells and retroviral gene therapy involves using a retrovirus to deliver genetic material. IVF (in vitro fertilization) does not apply to this scenario as it is a method of assisted reproductive technology and does not involve gene therapy.

Question 11

A retrovirus is given a functional version of a gene that a patient lacks and used to infect the patient's skin cells growing in culture.Skin is grown from the altered cells and grafted onto the patient.If all works well,the graft will

Accepted Answer

The retrovirus is used to insert a functional version of a missing gene in the patient's skin cells. This altered skin is then transplanted into the patient's body. If all goes well, the graft will be accepted by the patient's immune system and secrete the protein product of the inserted gene. Option A, C, D, and E are incorrect because the retrovirus is used to insert a functional gene, not activate an abnormal gene or lead to apoptosis.

Question 12

A nasal spray for cystic fibrosis patients,which contains adenovirus particles carrying a normal human CFTR gene,is an example of

Accepted Answer

The nasal spray for cystic fibrosis patients that contains adenovirus particles carrying a normal human CFTR gene is an example of in vivo gene therapy, as the gene therapy is being administered directly to the patient's body.

Question 13

Which is an example of a germline gene therapy?

Accepted Answer

Germline gene therapy involves altering genes in the germ cells (sperm, eggs, or embryos) so that the changes are heritable. A transgenic plant or animal involves altering the germline to introduce new traits, making it an example of germline gene therapy.

Question 14

Adenosine deaminase (ADA)deficiency results in

Accepted Answer

ADA deficiency results in severe combined immune deficiency, also known as "bubble boy" disease. This is because ADA is necessary for the development of functional T and B cells, resulting in a severely compromised immune system.

Question 15

Performing gene therapy on somatic cells removed from the body and then returned to the body is called _______ gene therapy.

Accepted Answer

Ex vivo gene therapy involves removing cells from the body, performing gene therapy on them in the lab, and then returning the cells to the body. This is different from in vivo gene therapy, where the gene therapy is performed directly in the body, and in situ gene therapy, where the gene therapy is performed at the site of the disease. In vitro refers to performing experiments or procedures outside of a living organism, and ex geno is not a commonly used phrase in the field of gene therapy.

Question 16

Gene therapy to treat muscular dystrophy targets the gene that encodes

Accepted Answer

Muscular dystrophy is caused by a mutation in the gene that encodes dystrophin, which is essential for muscle function. Gene therapy aims to replace the defective gene with a functional one.

Question 17

Using gene therapy to correct ornithine transcarbamylase deficiency (OTC)would prevent buildup of _________ in the blood.

Accepted Answer

Ornithine transcarbamylase deficiency (OTC) is a genetic disorder that results in the buildup of ammonia in the blood, which can lead to neurological damage and other serious health complications. Gene therapy has the potential to correct this deficiency by introducing a functional copy of the OTC gene into affected cells, thereby restoring proper metabolism of ammonia and preventing its accumulation in the blood.

Question 18

Introducing a gene in a liposome through holes bored into the skull is a(n)_______ gene therapy.

Accepted Answer

In vivo gene therapy involves introducing a gene directly into the body or target organ. In this case, the gene is introduced through the skull using liposomes. Ex vivo therapy takes place outside of the body, while in situ therapy targets the affected tissue directly without introducing the gene into the body. "Ex hubris" and "et al" are not relevant choices in this context.

Question 19

An effective vector to genetically alter respiratory cells might be

Accepted Answer

Adenovirus vectors are commonly used for gene therapy in the respiratory system as they can efficiently infect respiratory cells and have a strong ability to express foreign genes. Ti plasmids are commonly used in plant genetic engineering, while herpes simplex virus and HIV have been shown to cause disease in humans and are not appropriate choices for gene therapy. Human papilloma virus is most commonly associated with causing cervical cancer and is not an appropriate choice for respiratory gene therapy.

Question 20

The liver is a good candidate for gene therapy because

Accepted Answer

Only part of the liver may need to be corrected through gene therapy, as the liver has the ability to regenerate and function even if only a portion is functioning properly.

Quiz 20: Genetic Testing and Treatment