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

What is the function of the membrane attack complex (MAC) in the complement cascade?

  1. Activates the alternative complement pathway

  2. Promotes inflammation through anaphylatoxins

  3. Forms pores in the cell membrane, leading to cell lysis

  4. Binds to immune cells to initiate phagocytosis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The membrane attack complex (MAC) forms pores in the cell membrane of foreign cells, causing cell lysis and destruction.

Multiple choice

Which complement protein is involved in the regulation of the complement cascade, preventing excessive activation?

  1. C1 inhibitor

  2. Factor H

  3. C4 binding protein

  4. C5 convertase inhibitor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

C1 inhibitor is a regulatory protein that controls the classical complement pathway by inhibiting the activity of C1, preventing excessive activation.

Multiple choice

What is the role of C5a in the complement system?

  1. Activates neutrophils and macrophages

  2. Promotes inflammation through mast cell degranulation

  3. Inhibits the alternative complement pathway

  4. Binds to foreign cell surfaces to initiate opsonization
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

C5a is a complement protein that activates neutrophils and macrophages, promoting inflammation and enhancing phagocytosis.

Multiple choice

What is the role of properdin in the alternative complement pathway?

  1. Activates C3 convertase

  2. Stabilizes the C3 convertase complex

  3. Inhibits the classical complement pathway

  4. Binds to foreign cell surfaces to initiate opsonization
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Properdin is a protein that stabilizes the C3 convertase complex in the alternative complement pathway, enhancing its activity and promoting complement activation.

Multiple choice

Which complement protein is responsible for the generation of anaphylatoxins, such as C3a and C5a?

  1. C1q

  2. C3

  3. C4

  4. C5
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

C5 is the complement protein that undergoes cleavage to generate anaphylatoxins, including C3a and C5a, which have various inflammatory and immune-modulating effects.

Multiple choice

What is the role of C3aR and C5aR in the complement system?

  1. Inhibit the alternative complement pathway

  2. Bind to foreign cell surfaces to initiate opsonization

  3. Activate neutrophils and macrophages

  4. Regulate the activity of C3 convertase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

C3aR and C5aR are receptors for C3a and C5a, respectively. When activated, these receptors trigger various responses, including the activation of neutrophils and macrophages, promoting inflammation and phagocytosis.

Multiple choice

What is the role of factor D in the alternative complement pathway?

  1. Activates C3 convertase

  2. Cleaves C5 into C5a and C5b

  3. Stabilizes the C5 convertase complex

  4. Binds to foreign cell surfaces to initiate opsonization
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Factor D is a serine protease that activates C3 convertase in the alternative complement pathway, leading to the cleavage of C3 into C3a and C3b.

Multiple choice

What is the role of C4bp in the regulation of the complement system?

  1. Activates C3 convertase

  2. Inhibits the alternative complement pathway

  3. Stabilizes the C5 convertase complex

  4. Binds to foreign cell surfaces to initiate opsonization
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

C4bp (C4 binding protein) is a regulatory protein that inhibits the alternative complement pathway by binding to C4b and preventing its interaction with C2a, thereby preventing the formation of C3 convertase.

Multiple choice

What is the most common type of leukemia?

  1. Acute lymphoblastic leukemia (ALL)

  2. Acute myeloid leukemia (AML)

  3. Chronic lymphocytic leukemia (CLL)

  4. Chronic myeloid leukemia (CML)
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

ALL is the most common type of leukemia, accounting for about 25% of all cases.

Multiple choice

What is the most common type of allergic reaction?

  1. Anaphylaxis

  2. Hives

  3. Eczema

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

Hives are the most common type of allergic reaction. This occurs when the skin develops red, itchy welts.

Multiple choice

What is an antigen?

  1. A substance that triggers an immune response

  2. A type of white blood cell

  3. A protein produced by the immune system

  4. A type of antibody
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An antigen is any substance that is recognized by the immune system and triggers an immune response.

Multiple choice

What are the two main types of antigens?

  1. Exogenous and endogenous

  2. Humoral and cell-mediated

  3. Primary and secondary

  4. Active and passive
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Exogenous antigens are those that enter the body from outside, while endogenous antigens are those that are produced inside the body.

Multiple choice

What is the role of antigen-presenting cells (APCs) in the immune response?

  1. To phagocytize antigens and present them to T cells

  2. To produce antibodies against antigens

  3. To release cytokines that activate other immune cells

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

APCs are specialized cells that phagocytize antigens and present them to T cells, which are essential for the activation of the adaptive immune response.

Multiple choice

What are the two main types of T cells involved in the immune response to antigens?

  1. Helper T cells and cytotoxic T cells

  2. Regulatory T cells and memory T cells

  3. Naive T cells and effector T cells

  4. Central T cells and peripheral T cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Helper T cells help to activate other immune cells, while cytotoxic T cells kill infected cells.

Multiple choice

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

  1. To present antigens to T cells

  2. To activate B cells

  3. To produce antibodies

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

MHC molecules are cell surface proteins that present antigens to T cells, which are essential for the activation of the adaptive immune response.