Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

Which of the following is a potential challenge associated with cell transplantation?

  1. Rejection

  2. Infection

  3. Bleeding

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Rejection, infection, and bleeding are all potential challenges associated with cell transplantation.

Multiple choice

Which type of immune cell is primarily responsible for the rejection of implanted tissue constructs?

  1. T cells.

  2. B cells.

  3. Natural killer cells.

  4. Macrophages.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

T cells, particularly cytotoxic T cells, are the primary immune cells responsible for recognizing and attacking foreign antigens on implanted tissue constructs, leading to their rejection.

Multiple choice

What is the role of B cells in immune modulation in tissue engineering?

  1. They produce antibodies, which recognize and neutralize pathogens.

  2. They help in the activation of complement proteins, leading to the destruction of pathogens.

  3. They promote the differentiation of memory B cells, which provide long-term immunity.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

B cells play a crucial role in immune modulation in tissue engineering by producing antibodies, activating complement proteins, and promoting the differentiation of memory B cells, providing both humoral and long-term immunity.

Multiple choice

What is the role of the variable region in an antibody molecule?

  1. Binding to specific antigens

  2. Activating complement proteins

  3. Regulating immune responses

  4. Producing cytokines
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The variable region of an antibody molecule, located at the tips of the arms, is responsible for binding to specific antigens. It consists of hypervariable regions, also known as complementarity-determining regions (CDRs), which are highly diverse and allow antibodies to recognize a wide range of antigens.

Multiple choice

What type of phagocytosis do neutrophils primarily perform?

  1. Opsonization-dependent phagocytosis

  2. Opsonization-independent phagocytosis

  3. Both opsonization-dependent and opsonization-independent phagocytosis

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Neutrophils can perform both opsonization-dependent phagocytosis, which involves the recognition of opsonized particles via surface receptors, and opsonization-independent phagocytosis, where they directly recognize and engulf non-opsonized particles.

Multiple choice

Which surface receptors are primarily involved in opsonization-dependent phagocytosis by neutrophils?

  1. Fc receptors

  2. Complement receptors

  3. Toll-like receptors

  4. Mannose receptors
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Neutrophils express various surface receptors, including Fc receptors for recognizing antibodies bound to pathogens and complement receptors for recognizing complement proteins deposited on pathogens, enabling opsonization-dependent phagocytosis.

Multiple choice

What is the role of neutrophil extracellular traps (NETs) in phagocytosis?

  1. Immobilization of pathogens

  2. Killing of pathogens

  3. Recruitment of other immune cells

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophil extracellular traps (NETs) are structures formed by neutrophils during phagocytosis. NETs consist of DNA, histones, and antimicrobial proteins. They immobilize and kill pathogens, recruit other immune cells to the site of infection, and contribute to the overall host defense.

Multiple choice

Which cytokine is primarily responsible for neutrophil recruitment to the site of infection?

  1. Interleukin-1β (IL-1β)

  2. Tumor necrosis factor-α (TNF-α)

  3. Interleukin-8 (IL-8)

  4. Interferon-γ (IFN-γ)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Interleukin-8 (IL-8) is a potent chemotactic cytokine that plays a crucial role in neutrophil recruitment to the site of infection. It is produced by various cell types, including macrophages, endothelial cells, and epithelial cells, in response to infection or tissue damage.

Multiple choice

Which condition is characterized by an excessive or inappropriate activation of neutrophils?

  1. Neutropenia

  2. Neutrophilia

  3. Neutrophil dysfunction

  4. Neutrophil-mediated tissue damage
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophil-mediated tissue damage occurs when neutrophils release excessive amounts of reactive oxygen species (ROS), antimicrobial peptides, and proteolytic enzymes, leading to tissue destruction. This can contribute to the pathogenesis of various inflammatory diseases.

Multiple choice

What is the primary mechanism by which neutrophils kill ingested pathogens?

  1. Phagocytosis

  2. Degranulation

  3. Respiratory burst

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophils employ a combination of mechanisms to kill ingested pathogens. Phagocytosis involves engulfing the pathogen, degranulation releases antimicrobial peptides and enzymes into the phagosome, and the respiratory burst generates reactive oxygen species (ROS) that contribute to pathogen killing.

Multiple choice

What is the role of neutrophils in the innate immune response?

  1. Recognition of foreign pathogens

  2. Activation of the complement system

  3. Release of inflammatory mediators

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophils play a crucial role in the innate immune response by recognizing foreign pathogens through pattern recognition receptors (PRRs), activating the complement system via the release of complement proteins, and releasing inflammatory mediators such as cytokines and chemokines to recruit other immune cells to the site of infection.

Multiple choice

Which signaling pathway is primarily involved in neutrophil activation?

  1. Toll-like receptor (TLR) signaling

  2. Fc receptor (FcR) signaling

  3. Complement receptor (CR) signaling

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophil activation can be triggered by various signaling pathways, including Toll-like receptor (TLR) signaling, Fc receptor (FcR) signaling, and complement receptor (CR) signaling. These pathways lead to the production of reactive oxygen species (ROS), antimicrobial peptides, and the release of inflammatory mediators.

Multiple choice

What is the role of reactive oxygen species (ROS) in neutrophil phagocytosis?

  1. Killing of ingested pathogens

  2. Activation of NADPH oxidase

  3. Recruitment of other immune cells

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reactive oxygen species (ROS) play a crucial role in the killing of ingested pathogens by neutrophils. ROS are generated during the respiratory burst and have potent antimicrobial activity against a wide range of microorganisms.

Multiple choice

What type of cells are commonly targeted by NK cells?

  1. Red blood cells

  2. Neutrophils

  3. Virus-infected cells

  4. Plasma cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

NK cells primarily target and eliminate virus-infected cells, as well as cancerous cells, by releasing cytotoxic molecules that induce cell death.

Multiple choice

Which receptor on NK cells recognizes and binds to ligands expressed on target cells?

  1. TCR (T cell receptor)

  2. BCR (B cell receptor)

  3. KIR (Killer cell immunoglobulin-like receptor)

  4. CD4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

KIRs are expressed on the surface of NK cells and recognize specific ligands, known as KIR ligands, which are present on target cells. This interaction triggers NK cell activation and cytotoxicity.