Part 2 – Biotechnological Applications in Health: Gene Therapy & Stem Cell Technology

Q1.

Which of the following best defines gene therapy?
a) Replacing a defective gene with a normal one
b) Cloning of human embryos
c) Producing insulin using bacteria
d) Stimulating immune system artificially

Answer: a) Replacing a defective gene with a normal one

Explanation:

(a) Correct → Gene therapy is about correcting defective genes.
(b) Cloning → Not gene therapy.
(c) Insulin in bacteria → rDNA technology, not gene therapy.
(d) Immunotherapy is different, not gene therapy.

Q2.

Which was the first human disease successfully treated by gene therapy?
a) Hemophilia
b) Severe Combined Immunodeficiency (SCID)
c) Cystic Fibrosis
d) Muscular Dystrophy

Answer: b) Severe Combined Immunodeficiency (SCID)

Explanation:

(a) Hemophilia → Gene therapy attempted, but not first.
(b) SCID → Correct, first gene therapy (1990, Ashanti DeSilva).
(c) Cystic Fibrosis → Still experimental.
(d) Muscular Dystrophy → Research stage.

Q3.

SCID is caused by a defect in the gene coding for:
a) Adenosine deaminase (ADA)
b) Hemoglobin
c) Insulin
d) Collagen

Answer: a) Adenosine deaminase (ADA)

Explanation:

(a) ADA → Correct, its deficiency leads to SCID.
(b) Hemoglobin → Causes thalassemia, not SCID.
(c) Insulin → Diabetes mellitus, not SCID.
(d) Collagen → Connective tissue disorders, not SCID.

Q4.

In ex vivo gene therapy for ADA deficiency, lymphocytes are:
a) Removed from bone marrow, corrected, and reintroduced
b) Treated inside the patient with DNA vectors
c) Stimulated with growth factors only
d) Destroyed and replaced with donor cells

Answer: a) Removed from bone marrow, corrected, and reintroduced

Explanation:

(a) Correct → Cells taken out, corrected with functional ADA gene, then reinfused.
(b) In vivo therapy → Different method.
(c) Growth factors → Do not replace genes.
(d) Replacement → Not gene therapy, that’s bone marrow transplant.

Q5.

Which of the following vectors is commonly used in gene therapy?
a) Retrovirus
b) Plasmid DNA only
c) Prions
d) Ribozymes

Answer: a) Retrovirus

Explanation:

(a) Correct → Retroviruses integrate DNA into host genome.
(b) Plasmid DNA → Limited efficiency in humans.
(c) Prions → Infectious proteins, not used.
(d) Ribozymes → Catalytic RNAs, not vectors.

Q6.

Which type of gene therapy targets only somatic cells, not germline cells?
a) In vivo therapy
b) Ex vivo therapy
c) Somatic cell gene therapy
d) Germline gene therapy

Answer: c) Somatic cell gene therapy

Explanation:

(a) In vivo → Direct treatment, not necessarily somatic-only.
(b) Ex vivo → Done outside body, but both can apply.
(c) Correct → Targets only body (somatic) cells, not heritable.
(d) Germline → Alters gametes/embryos, heritable.

Q7.

Which of the following is a major limitation of gene therapy?
a) Ethical concerns
b) Difficulty in targeting specific cells
c) Risk of immune response
d) All of the above

Answer: d) All of the above

Explanation:

(a) Ethics → True, especially for germline therapy.
(b) Targeting → A real technical problem.
(c) Immune response → Viral vectors may cause rejection.
(d) All of the above → Correct.

Q8.

The technique where a normal gene is directly introduced into tissues inside the patient’s body is called:
a) Ex vivo gene therapy
b) In vivo gene therapy
c) Somatic gene therapy
d) Germline therapy

Answer: b) In vivo gene therapy

Explanation:

(a) Ex vivo → Done outside patient.
(b) Correct → Directly inside patient.
(c) Somatic → General term, may include in vivo/ex vivo.
(d) Germline → Embryo/gametes, not in vivo.

Q9.

Stem cells are defined as cells that:
a) Divide rapidly without limit
b) Can differentiate into one or more cell types
c) Are only present in embryos
d) Are terminally differentiated

Answer: b) Can differentiate into one or more cell types

Explanation:

(a) Rapid division → Not always true.
(b) Correct → Stem cells are undifferentiated with differentiation potential.
(c) Incorrect → Also found in adults.
(d) Incorrect → Differentiated cells cannot revert.

Q10.

Embryonic stem cells are considered pluripotent because:
a) They can form all cell types of the body
b) They form only blood cells
c) They are immortal
d) They cannot differentiate

Answer: a) They can form all cell types of the body

Explanation:

(a) Correct → Pluripotent cells form all body cell types.
(b) Incorrect → That’s multipotent, like bone marrow stem cells.
(c) Incorrect → Not immortal.
(d) Incorrect → They can differentiate.

Q11.

Which of the following is a source of adult stem cells?
a) Umbilical cord blood
b) Bone marrow
c) Adipose tissue
d) All of the above

Answer: d) All of the above

Explanation:

(a) Umbilical cord → True.
(b) Bone marrow → True.
(c) Adipose tissue → True.
(d) Correct → All of these provide adult stem cells.

Q12.

Hematopoietic stem cells are responsible for:
a) Repairing nerve cells
b) Producing blood cells
c) Healing skin wounds
d) Bone regeneration

Answer: b) Producing blood cells

Explanation:

(a) Incorrect → Neural stem cells repair nerves.
(b) Correct → Hematopoietic stem cells give rise to RBCs, WBCs, platelets.
(c) Incorrect → Skin stem cells do that.
(d) Incorrect → Bone marrow stem cells may regenerate bone, but hematopoietic are specific to blood.

Q13.

Which type of stem cells are used in bone marrow transplantation?
a) Pluripotent embryonic stem cells
b) Hematopoietic stem cells
c) Mesenchymal stem cells
d) Induced pluripotent stem cells

Answer: b) Hematopoietic stem cells

Explanation:

(a) Incorrect → Embryonic stem cells not used clinically.
(b) Correct → Bone marrow transplant uses hematopoietic stem cells.
(c) Incorrect → Mesenchymal cells are different.
(d) Incorrect → iPS cells are experimental.

Q14.

Induced pluripotent stem (iPS) cells are created by:
a) Exposing differentiated cells to mutagens
b) Reprogramming adult cells with specific genes
c) Removing nucleus and inserting new DNA
d) Fusion of two stem cells

Answer: b) Reprogramming adult cells with specific genes

Explanation:

(a) Mutagens → Cause mutations, not pluripotency.
(b) Correct → Yamanaka factors reprogram somatic cells.
(c) Nuclear transfer → Different technique.
(d) Fusion → Not iPS technology.

Q15.

Which of the following diseases is NOT currently targeted by stem cell therapy research?
a) Parkinson’s disease
b) Diabetes
c) Alzheimer’s disease
d) Common cold

Answer: d) Common cold

Explanation:

(a) Parkinson’s → Target for neural stem cells.
(b) Diabetes → Pancreatic beta-cell regeneration studied.
(c) Alzheimer’s → Neural stem cell research ongoing.
(d) Common cold → Caused by viruses, not stem cell target.

Q16.

A major ethical concern with embryonic stem cells is:
a) Risk of immune rejection
b) Destruction of embryos
c) Low growth rate
d) Cost of culture media

Answer: b) Destruction of embryos

Explanation:

(a) Rejection → True but not ethical issue.
(b) Correct → Embryo destruction raises ethical debates.
(c) Incorrect → Embryonic stem cells divide well.
(d) Cost → Not ethical, but practical.

Q17.

Which property distinguishes embryonic stem cells from adult stem cells?
a) Ability to divide
b) Pluripotency
c) Presence in all tissues
d) Short lifespan

Answer: b) Pluripotency

Explanation:

(a) Both can divide.
(b) Correct → Embryonic are pluripotent, adult are multipotent.
(c) Incorrect → Adult stem cells are tissue-specific.
(d) Incorrect → Lifespan varies.

Q18.

Which of the following methods is used to deliver genes in gene therapy?
a) Liposomes
b) Electroporation
c) Viral vectors
d) All of the above

Answer: d) All of the above

Explanation:

(a) Liposomes → Synthetic carriers.
(b) Electroporation → Electric pulses introduce DNA.
(c) Viral vectors → Common carriers.
(d) Correct → All methods are used.

Q19.

Which statement about somatic cell gene therapy is TRUE?
a) The effects are heritable
b) It modifies gametes
c) It affects only the treated individual
d) It is banned worldwide

Answer: c) It affects only the treated individual

Explanation:

(a) Incorrect → Not heritable.
(b) Incorrect → Does not affect gametes.
(c) Correct → Only patient benefits.
(d) Incorrect → It is permitted with regulations.

Q20.

The first clinical gene therapy trial used:
a) Retrovirus as vector
b) Liposomes as vector
c) CRISPR technology
d) Naked DNA injection

Answer: a) Retrovirus as vector

Explanation:

(a) Correct → ADA-SCID therapy used retrovirus.
(b) Incorrect → Liposomes less efficient.
(c) Incorrect → CRISPR is recent.
(d) Incorrect → Naked DNA not efficient.

Q21.

Stem cell therapy for spinal cord injury aims at:
a) Blocking nerve impulses
b) Regenerating nerve cells
c) Producing hormones
d) Preventing infections

Answer: b) Regenerating nerve cells

Explanation:

(a) Blocking → Not useful.
(b) Correct → Goal is neural regeneration.
(c) Incorrect → Hormone production unrelated.
(d) Incorrect → Not infection therapy.

Q22.

Which of the following is NOT a stem cell property?
a) Self-renewal
b) Differentiation
c) Terminal differentiation
d) Clonogenicity

Answer: c) Terminal differentiation

Explanation:

(a) True → Self-renew.
(b) True → Differentiate into cell types.
(c) Correct → Once terminally differentiated, a cell is no longer a stem cell.
(d) True → Stem cells can form clones.

Q23.

Which Nobel Prize-winning discovery is directly related to stem cells?
a) Induced pluripotent stem cells (iPS) – Shinya Yamanaka
b) Insulin production – Banting and Best
c) Double helix structure of DNA – Watson and Crick
d) PCR – Kary Mullis

Answer: a) Induced pluripotent stem cells (iPS) – Shinya Yamanaka

Explanation:

(a) Correct → Nobel Prize 2012 for iPS discovery.
(b) Insulin → Important, but not stem cells.
(c) DNA helix → Genetics, not stem cells.
(d) PCR → DNA amplification, not stem cells.

Q24.

Which of the following is an example of autologous stem cell therapy?
a) Using patient’s own bone marrow cells
b) Using donor’s stem cells
c) Using embryonic stem cells
d) Using iPS cells from another person

Answer: a) Using patient’s own bone marrow cells

Explanation:

(a) Correct → Autologous means from the same individual.
(b) Donor → Allogeneic.
(c) Embryonic → Not autologous.
(d) iPS from another person → Not autologous.

Q25.

Which is the most promising tool for precise gene editing in gene therapy today?
a) Retrovirus
b) CRISPR-Cas9
c) Electroporation
d) Liposome-mediated transfer

Answer: b) CRISPR-Cas9

Explanation:

(a) Retrovirus → Older method.
(b) Correct → CRISPR is precise and revolutionary.
(c) Electroporation → Delivery method, less precise.
(d) Liposomes → Delivery, not editing tool.

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Part 2 – Biotechnological Applications in Health: Gene Therapy & Stem Cell Technology