Question 1

Which of the following best describes the role of PCR (Polymerase Chain Reaction) in genetic engineering?

Accepted Answer

PCR is used to amplify specific DNA sequences, enabling cloning and analysis.

Question 2

A researcher wants to create a genetically modified organism (GMO) that is resistant to a specific antibiotic. Which technique would most likely be used to confirm the presence of the resistance gene in the organism?

Accepted Answer

Hybridization using FISH (fluorescence in situ hybridization)

Question 3

Which of the following is a key function of the gut-brain axis in human health?

Accepted Answer

Regulation of mood and behavior through microbial metabolites

Question 4

A patient is exposed to a bacterial pathogen that produces endotoxin. Which of the following best explains the potential consequence?

Accepted Answer

Endotoxin can trigger pyrogenic responses, leading to fever and inflammation.

Question 5

Which immune cell type is primarily responsible for antigen presentation to T cells?

Accepted Answer

Dendritic cells

Question 6

A scientist is designing a monoclonal antibody to target a cancer cell surface protein. Which process is essential for producing monoclonal antibodies?

Accepted Answer

Fusion of B cells with myeloma cells to create hybridomas

Question 7

Which of the following best describes the function of TLRs (Toll-like receptors) in the immune system?

Accepted Answer

TLRs recognize pathogen-associated molecular patterns and activate innate immunity.

Question 8

A patient with a genetic defect in GALT (galactose-1-phosphate uridyltransferase) is most likely to experience which of the following?

Accepted Answer

Impaired metabolism of galactose leading to toxic accumulation

Question 9

Which of the following is a consequence of complement activation in the immune response?

Accepted Answer

Opsonization of pathogens, enhancing phagocytosis

Question 10

A researcher is studying the effect of a new drug on the LD50 of a bacterial toxin. If the LD50 increases after drug treatment, what does this indicate?

Accepted Answer

The drug reduces the toxicity of the bacterial toxin.

Question 11

Which of the following best explains why spontaneous cancer remission may occur after infection?

Accepted Answer

Activation of the immune system by infection can lead to destruction of cancer cells.

Question 12

Which of the following is a major difference between innate and adaptive immunity?

Accepted Answer

Adaptive immunity generates memory cells for faster response upon re-exposure.

Question 13

A patient is diagnosed with an autoimmune disease. Which of the following best describes the underlying cause?

Accepted Answer

The immune system attacks self-antigens, mistaking them for foreign invaders.

Question 14

Which of the following best describes the function of NK (Natural Killer) cells?

Accepted Answer

NK cells destroy infected or cancerous cells by recognizing abnormal surface markers.

Question 15

Which of the following is a real-world application of CRISPR-Cas9 technology?

Accepted Answer

Editing genes to correct inherited genetic disorders

Question 16

A patient receives a vaccine containing inactivated virus. Which immune response is most likely to be stimulated?

Accepted Answer

Production of specific antibodies by B cells

Question 17

Which of the following best explains the concept of 'keystone species' in the microbiome?

Accepted Answer

A keystone species has a disproportionately large effect on the structure and function of the microbial community.

Question 18

A scientist is analyzing the effect of a mutation in the host's physical barriers. Which of the following is most likely to occur?

Accepted Answer

Increased susceptibility to pathogen invasion due to compromised barriers

Question 19

Which of the following equations correctly represents the calculation of LD50 (lethal dose 50%)?

Accepted Answer

$$LD_{50} = 	ext{Dose at which 50\% of test population dies}$$

Question 20

A patient with a deficiency in complement proteins is most likely to experience which of the following?

Accepted Answer

Increased susceptibility to bacterial infections due to impaired opsonization

Microbiology Exam 3 Review: Biotechnology, Immunity, and Host-Pathogen Interactions

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