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 type of MHC molecule is recognized by αβ T cell receptors?

  1. MHC class I

  2. MHC class II

  3. Both MHC class I and class II

  4. Neither MHC class I nor class II
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

αβ T cell receptors can recognize antigens presented on both MHC class I and class II molecules. MHC class I molecules present antigens derived from intracellular pathogens, while MHC class II molecules present antigens derived from extracellular pathogens.

Multiple choice

Which type of MHC molecule is recognized by γδ T cell receptors?

  1. MHC class I

  2. MHC class II

  3. Both MHC class I and class II

  4. Neither MHC class I nor class II
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

γδ T cell receptors do not recognize antigens presented on MHC molecules. Instead, they recognize non-peptide antigens, such as lipids and phosphoantigens, that are presented by other molecules on the surface of cells.

Multiple choice

What is the role of CD4 and CD8 co-receptors in T cell activation?

  1. They bind to MHC molecules and help stabilize the interaction between the TCR and MHC-antigen complex.

  2. They bind to antigens and help deliver them to the TCR.

  3. They bind to other T cells and help form an immunological synapse.

  4. They bind to cytokines and help regulate T cell responses.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CD4 and CD8 co-receptors bind to MHC molecules on the surface of antigen-presenting cells and help stabilize the interaction between the TCR and the MHC-antigen complex. This interaction is essential for the activation of T cells.

Multiple choice

What is the role of the Lck tyrosine kinase in T cell activation?

  1. It phosphorylates the ζ-chain and other signaling molecules, leading to T cell activation.

  2. It binds to the TCR and helps stabilize the TCR-MHC-antigen interaction.

  3. It helps recruit other signaling molecules to the TCR complex.

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

The Lck tyrosine kinase is a signaling molecule that is associated with the TCR complex. It phosphorylates the ζ-chain and other signaling molecules, leading to T cell activation.

Multiple choice

What is the role of the PLCγ1 enzyme in T cell activation?

  1. It hydrolyzes PIP2 to generate IP3 and DAG, leading to increased intracellular calcium levels and activation of PKC.

  2. It binds to the TCR and helps stabilize the TCR-MHC-antigen interaction.

  3. It helps recruit other signaling molecules to the TCR complex.

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

The PLCγ1 enzyme is a signaling molecule that is associated with the TCR complex. It hydrolyzes PIP2 to generate IP3 and DAG, leading to increased intracellular calcium levels and activation of PKC.

Multiple choice

What is the name of the treatment that uses the body's own immune system to fight cancer?

  1. Immunotherapy

  2. Radiotherapy

  3. Chemotherapy

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

Immunotherapy uses the body's own immune system to fight cancer.

Multiple choice

What are antigens?

  1. Substances that trigger an immune response

  2. Antibodies produced by the immune system

  3. Cells that recognize and attack antigens

  4. Proteins found in the blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Antigens are substances that are recognized by the immune system as foreign and potentially harmful. They can be proteins, carbohydrates, lipids, or nucleic acids.

Multiple choice

What are the two main types of antigens?

  1. Exogenous and endogenous antigens

  2. Humoral and cell-mediated antigens

  3. Primary and secondary antigens

  4. Native and denatured antigens
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Exogenous antigens are those that enter the body from the outside environment, such as bacteria, viruses, and toxins. Endogenous antigens are those that are produced inside the body, such as cancer cells and proteins that are released from damaged cells.

Multiple choice

What are epitopes?

  1. The parts of an antigen that are recognized by antibodies

  2. The parts of an antigen that are recognized by T cells

  3. The parts of an antigen that are recognized by both antibodies and T cells

  4. The parts of an antigen that are not recognized by the immune system
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Epitopes are the parts of an antigen that are recognized by antibodies. They are usually small, linear sequences of amino acids or sugars.

Multiple choice

What is the role of MHC molecules in the immune response?

  1. To present antigens to T cells

  2. To activate B cells

  3. To produce antibodies

  4. To kill infected cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

MHC molecules are proteins that are found on the surface of all cells. They present antigens to T cells, which then become activated and can kill infected cells or help B cells produce antibodies.

Multiple choice

What are the two main types of MHC molecules?

  1. MHC class I and MHC class II

  2. MHC class A and MHC class B

  3. MHC class I and MHC class III

  4. MHC class II and MHC class III
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There are two main types of MHC molecules: MHC class I and MHC class II. MHC class I molecules are found on all cells, while MHC class II molecules are found only on antigen-presenting cells, such as macrophages and dendritic cells.

Multiple choice

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

  1. Humoral immunity involves the production of antibodies, while cell-mediated immunity involves the activation of T cells

  2. Humoral immunity is more effective against extracellular pathogens, while cell-mediated immunity is more effective against intracellular pathogens

  3. Humoral immunity is faster than cell-mediated immunity

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

Humoral immunity involves the production of antibodies by B cells, while cell-mediated immunity involves the activation of T cells. Humoral immunity is more effective against extracellular pathogens, while cell-mediated immunity is more effective against intracellular pathogens. Humoral immunity is faster than cell-mediated immunity.

Multiple choice

Which type of immune cells are responsible for immunological memory?

  1. B cells

  2. T cells

  3. Macrophages

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

Both B cells and T cells play a role in immunological memory. B cells produce antibodies, while T cells help to activate B cells and kill infected cells.

Multiple choice

What are memory B cells?

  1. B cells that have been exposed to a pathogen and are now able to produce antibodies against it.

  2. B cells that are produced in the bone marrow.

  3. B cells that are found in the lymph nodes.

  4. B cells that are responsible for producing antibodies against self-antigens.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Memory B cells are a type of B cell that has been exposed to a pathogen and is now able to produce antibodies against it. These cells are long-lived and can provide protection against future infections.

Multiple choice

What are memory T cells?

  1. T cells that have been exposed to a pathogen and are now able to kill infected cells.

  2. T cells that are produced in the thymus.

  3. T cells that are found in the spleen.

  4. T cells that are responsible for regulating the immune response.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Memory T cells are a type of T cell that has been exposed to a pathogen and is now able to kill infected cells. These cells are long-lived and can provide protection against future infections.