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 molecule is recognized by T cells to initiate an immune response?

  1. Antibodies

  2. Antigens

  3. Cytokines

  4. Complement proteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

T cells recognize antigens presented on the surface of antigen-presenting cells (APCs) via major histocompatibility complex (MHC) molecules.

Multiple choice

What is the role of MHC molecules in cell-mediated immunity?

  1. They present antigens to T cells.

  2. They activate cytotoxic T cells.

  3. They produce antibodies to neutralize pathogens.

  4. They suppress the immune response to prevent excessive inflammation.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

MHC molecules bind to antigens and present them on the surface of APCs, allowing T cells to recognize and respond to the antigens.

Multiple choice

Which type of MHC molecule is responsible for presenting antigens to CD8+ cytotoxic T cells?

  1. MHC class I

  2. MHC class II

  3. MHC class III

  4. MHC class IV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

MHC class I molecules present antigens to CD8+ cytotoxic T cells, which are responsible for killing infected or cancerous cells.

Multiple choice

Which type of MHC molecule is responsible for presenting antigens to CD4+ helper T cells?

  1. MHC class I

  2. MHC class II

  3. MHC class III

  4. MHC class IV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

MHC class II molecules present antigens to CD4+ helper T cells, which activate other immune cells and help B cells produce antibodies.

Multiple choice

What is the role of memory T cells in cell-mediated immunity?

  1. They directly kill infected or cancerous cells.

  2. They activate cytotoxic T cells and B cells.

  3. They provide long-term immunity by responding quickly to reinfection.

  4. They suppress the immune response to prevent excessive inflammation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Memory T cells remain in the body after an infection and can quickly respond to the same pathogen if it is encountered again, providing long-term immunity.

Multiple choice

What is the difference between cell-mediated immunity and humoral immunity?

  1. Cell-mediated immunity involves T cells, while humoral immunity involves B cells.

  2. Cell-mediated immunity targets intracellular pathogens, while humoral immunity targets extracellular pathogens.

  3. Cell-mediated immunity provides long-term immunity, while humoral immunity provides short-term immunity.

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

Cell-mediated immunity involves T cells and targets intracellular pathogens, while humoral immunity involves B cells and targets extracellular pathogens. Cell-mediated immunity also provides long-term immunity through memory T cells.

Multiple choice

Which cytokine is produced by helper T cells to activate cytotoxic T cells?

  1. Interleukin-2 (IL-2)

  2. Interleukin-4 (IL-4)

  3. Interleukin-10 (IL-10)

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

Interleukin-2 (IL-2) is a cytokine produced by helper T cells that activates cytotoxic T cells and promotes their proliferation.

Multiple choice

What is the role of natural killer (NK) cells in cell-mediated immunity?

  1. They directly kill infected or cancerous cells.

  2. They activate cytotoxic T cells and B cells.

  3. They produce antibodies to neutralize pathogens.

  4. They suppress the immune response to prevent excessive inflammation.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Natural killer (NK) cells are a type of innate immune cell that can directly kill infected or cancerous cells without prior sensitization.

Multiple choice

Which molecule is expressed on the surface of cytotoxic T cells and is responsible for killing target cells?

  1. CD4

  2. CD8

  3. TCR

  4. MHC
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CD8 is a molecule expressed on the surface of cytotoxic T cells that binds to MHC class I molecules on target cells, allowing the cytotoxic T cell to kill the target cell.

Multiple choice

What is the role of regulatory T cells (Tregs) in cell-mediated immunity?

  1. They directly kill infected or cancerous cells.

  2. They activate cytotoxic T cells and B cells.

  3. They suppress the immune response to prevent excessive inflammation.

  4. They produce antibodies to neutralize pathogens.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Regulatory T cells (Tregs) are a type of T cell that suppresses the immune response to prevent excessive inflammation and autoimmune reactions.

Multiple choice

Which cytokine is produced by helper T cells to activate macrophages and promote phagocytosis?

  1. Interleukin-2 (IL-2)

  2. Interleukin-4 (IL-4)

  3. Interleukin-10 (IL-10)

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

Interferon-gamma (IFN-γ) is a cytokine produced by helper T cells that activates macrophages and promotes phagocytosis, helping to clear intracellular pathogens.

Multiple choice

Which of the following is an example of medical terminology?

  1. Hypertension

  2. Inflammation

  3. Hemoglobin

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

Medical terminology is the specialized language used in medicine to describe diseases, treatments, and other medical concepts. Hypertension, inflammation, and hemoglobin are all examples of medical terminology.

Multiple choice

What is the term for the mistaken attack of the immune system on healthy body tissue?

  1. Autoimmunity

  2. Allergy

  3. Infection

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

Autoimmunity occurs when the immune system mistakenly recognizes and attacks its own body's tissues, leading to tissue damage and dysfunction.

Multiple choice

Which type of immune cell is primarily responsible for recognizing and attacking foreign invaders?

  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, play a crucial role in recognizing and eliminating infected or cancerous cells, as well as foreign invaders.

Multiple choice

What is the role of B cells in the immune response?

  1. Producing antibodies

  2. Engulfing foreign particles

  3. Releasing inflammatory chemicals

  4. Activating T cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

B cells are responsible for producing antibodies, which are proteins that recognize and bind to specific antigens, marking them for destruction.