Antigen/Antibody Reactions

Question 1

What is an antigen?

Answer 1

An antigen is a substance that triggers an immune response, typically by being recognized by antibodies.

Question 2

True or False: Antigens can be proteins, polysaccharides, or nucleic acids.

Answer 2

True

Question 3

Fill in the blank: The primary function of antibodies is to __________ antigens.

Answer 3

neutralize

Question 4

What are the five main classes of immunoglobulins?

Answer 4

IgG, IgA, IgM, IgE, and IgD

Question 5

Which immunoglobulin is the most abundant in serum?

Answer 5

IgG

Question 6

Multiple Choice: Which immunoglobulin is primarily found in mucosal areas? A) IgG B) IgA C) IgM D) IgE

Answer 6

B) IgA

Question 7

What role does IgM play in the immune response?

Answer 7

IgM is the first antibody produced in response to an infection and is effective in forming complexes with antigens.

Question 8

True or False: IgE is primarily involved in allergic reactions and responses to parasitic infections.

Answer 8

True

Question 9

What is the structure of antibodies?

Answer 9

Antibodies are Y-shaped molecules consisting of two heavy chains and two light chains.

Question 10

Fill in the blank: The region of the antibody that binds to the antigen is called the __________.

Answer 10

antigen-binding site

Question 11

Which immunoglobulin is found on the surface of B cells?

Answer 11

IgD

Question 12

Multiple Choice: Which class of immunoglobulin is involved in the body’s first line of defense? A) IgG B) IgA C) IgM D) IgE

Answer 12

C) IgM

Question 13

What is the main function of IgA?

Answer 13

IgA plays a crucial role in mucosal immunity by preventing the colonization of pathogens.

Question 14

True or False: Antibodies can directly destroy pathogens.

Answer 14

False

Question 15

What type of immunity do antibodies provide?

Answer 15

Humoral immunity

Question 16

Fill in the blank: Antigens that are derived from pathogens are called __________ antigens.

Answer 16

infectious

Question 17

What is the difference between a T-dependent and T-independent antigen?

Answer 17

T-dependent antigens require T cell help for B cell activation, while T-independent antigens can activate B cells directly.

Question 18

Multiple Choice: Which immunoglobulin is associated with allergic reactions? A) IgG B) IgA C) IgM D) IgE

Answer 18

D) IgE

Question 19

What is the role of memory B cells?

Answer 19

Memory B cells provide long-term immunity by quickly producing antibodies upon re-exposure to the same antigen.

Question 20

True or False: All antibodies are produced by the same type of B cell.

Answer 20

False

Question 21

What triggers the production of antibodies?

Answer 21

The presence of antigens in the body triggers the production of antibodies.

Question 22

Fill in the blank: The part of the immune system that specifically targets antigens is called __________ immunity.

Answer 22

adaptive

Question 23

Which immunoglobulin is the first to appear in the bloodstream after an infection?

Answer 23

IgM

Question 24

Multiple Choice: Which class of immunoglobulin can cross the placenta? A) IgG B) IgA C) IgM D) IgE

Answer 24

A) IgG

Question 25

What is the significance of the constant region of an antibody?

Answer 25

The constant region determines the class of the antibody and mediates its effector functions.

Question 26

True or False: Antigens can only be proteins.

Answer 26

False

Question 27

What is a hapten?

Answer 27

A hapten is a small molecule that can elicit an immune response only when attached to a larger carrier protein.

Question 28

Fill in the blank: The process by which antibodies mark pathogens for destruction is called __________.

Answer 28

opsonization

Question 29

What is the difference between active and passive immunity?

Answer 29

Active immunity results from exposure to an antigen and the production of antibodies, while passive immunity involves the transfer of antibodies from another source.

Question 30

Multiple Choice: Which immunoglobulin is primarily involved in immune responses to helminths? A) IgG B) IgA C) IgM D) IgE

Answer 30

D) IgE

Question 31

What is papain?

Answer 31

Papain is a proteolytic enzyme derived from the papaya fruit.

Question 32

True or False: Papain can break down disulfide bonds.

Answer 32

True.

Question 33

What are disulfide bonds?

Answer 33

Disulfide bonds are covalent bonds formed between the sulfur atoms of cysteine residues in proteins.

Question 34

Fill in the blank: The Fab region of an antibody is responsible for _______.

Answer 34

antigen binding.

Question 35

What does Fc stand for in the context of antibodies?

Answer 35

Fc stands for fragment crystallizable.

Question 36

Multiple Choice: Which part of the antibody mediates immune cell interactions? A) Fab B) Fc C) Both

Answer 36

B) Fc.

Question 37

What is the primary function of the Fab region?

Answer 37

To bind specifically to antigens.

Question 38

True or False: The Fc region can activate complement proteins.

Answer 38

True.

Question 39

Fill in the blank: Disulfide bonds stabilize the _______ structure of proteins.

Answer 39

tertiary.

Question 40

How many disulfide bonds are typically found in an IgG antibody?

Answer 40

Four disulfide bonds.

Question 41

What type of bond is formed between two cysteine residues?

Answer 41

A disulfide bond.

Question 42

Multiple Choice: Which enzyme is commonly used in research to study protein structure? A) Papain B) Amylase C) Lipase

Answer 42

A) Papain.

Question 43

What is the role of papain in protein digestion?

Answer 43

To cleave peptide bonds in proteins.

Question 44

True or False: The Fab region consists of heavy and light chains.

Answer 44

True.

Question 45

Fill in the blank: The Fc region of antibodies is involved in _______ signaling.

Answer 45

immune.

Question 46

What kind of enzyme activity does papain exhibit?

Answer 46

Proteolytic activity.

Question 47

Multiple Choice: Which of the following is NOT a function of the Fc region? A) Antigen binding B) Complement activation C) Binding to Fc receptors

Answer 47

A) Antigen binding.

Question 48

What structural feature allows disulfide bonds to form?

Answer 48

Oxidation of thiol groups (-SH) in cysteine.

Question 49

True or False: Papain can be used in meat tenderizers.

Answer 49

True.

Question 50

What is the significance of the hinge region in antibodies?

Answer 50

It allows flexibility between the Fab and Fc regions.

Question 51

Fill in the blank: Papain can cleave antibodies at the _______ region.

Answer 51

hinge.

Question 52

What is the effect of reducing agents on disulfide bonds?

Answer 52

They break disulfide bonds.

Question 53

Multiple Choice: Which of the following antibodies has a higher number of disulfide bonds? A) IgG B) IgM C) IgA

Answer 53

B) IgM.

Question 54

What type of bond stabilizes the structure of the Fab region?

Answer 54

Disulfide bonds.

Question 55

True or False: The Fc region can be involved in opsonization.

Answer 55

True.

Question 56

Fill in the blank: The Fab region is also known as the _______ fragment.

Answer 56

antigen-binding.

Question 57

What is chemotaxis?

Answer 57

Chemotaxis is the movement of an organism or cell in response to a chemical stimulus.

Question 58

True or False: Phagocytosis is a process used by cells to engulf and digest large particles.

Answer 58

True

Question 59

Fill in the blank: The ______ zone is the range of antibody concentrations where the amount of antigen and antibody are balanced.

Answer 59

zone of equivalence

Question 60

What occurs in the prozone phenomenon?

Answer 60

In the prozone phenomenon, an excess of antibody inhibits the formation of visible immune complexes.

Question 61

What is the postzone phenomenon?

Answer 61

The postzone phenomenon occurs when there is an excess of antigen, leading to a lack of visible immune complexes.

Question 62

Multiple Choice: Which of the following processes is primarily responsible for the removal of pathogens from the body? A) Chemotaxis B) Phagocytosis C) Both A and B D) None of the above

Answer 62

C) Both A and B

Question 63

What type of cells are primarily involved in phagocytosis?

Answer 63

Macrophages and neutrophils are primarily involved in phagocytosis.

Question 64

True or False: The zone of equivalence is characterized by a high concentration of free antigen.

Answer 64

False

Question 65

What is the primary function of chemotaxis in the immune response?

Answer 65

The primary function of chemotaxis in the immune response is to guide immune cells to sites of infection or inflammation.

Question 66

Fill in the blank: The ______ zone is where the amount of antigen exceeds the amount of antibody.

Answer 66

postzone

Question 67

What role do cytokines play in chemotaxis?

Answer 67

Cytokines act as signaling molecules that attract immune cells to the site of infection.

Question 68

Multiple Choice: Which type of immune response primarily utilizes phagocytosis? A) Humoral immunity B) Cell-mediated immunity C) Both A and B D) None of the above

Answer 68

B) Cell-mediated immunity

Question 69

What is the significance of the zone of equivalence in immunological assays?

Answer 69

The zone of equivalence is significant as it allows for optimal detection of antigen-antibody complexes.

Question 70

True or False: Chemotaxis occurs only in response to pathogens.

Answer 70

False

Question 71

What triggers the process of phagocytosis?

Answer 71

Phagocytosis is triggered by the recognition of pathogens or foreign particles by immune cells.

Question 72

Fill in the blank: In the prozone phenomenon, the excessive concentration of ______ can lead to false-negative results in immunological tests.

Answer 72

antibodies

Question 73

What is the relationship between chemotaxis and inflammation?

Answer 73

Chemotaxis is a critical process during inflammation, directing immune cells to the site of tissue damage or infection.

Question 74

Multiple Choice: Which of the following best describes phagocytosis? A) Active transport B) Passive diffusion C) Endocytosis D) Osmosis

Answer 74

C) Endocytosis

Question 75

What is the function of opsonins in phagocytosis?

Answer 75

Opsonins enhance the ability of phagocytes to recognize and engulf pathogens.

Question 76

True or False: The postzone phenomenon can complicate the interpretation of serological tests.

Answer 76

True

Question 77

Fill in the blank: The process of ______ allows immune cells to move toward higher concentrations of signaling molecules.

Answer 77

chemotaxis

Question 78

What is the effect of a high concentration of antigen in the postzone?

Answer 78

A high concentration of antigen can lead to a decrease in immune complex formation, complicating immune responses.

Question 79

What are the two main types of chemotactic signals?

Answer 79

The two main types of chemotactic signals are endogenous (produced by the body) and exogenous (produced by pathogens).

Question 80

Fill in the blank: Phagocytosis involves the formation of a ______ that encases the particle to be ingested.

Answer 80

phagosome

Question 81

What is the outcome of successful phagocytosis?

Answer 81

The successful outcome of phagocytosis is the destruction and clearance of pathogens from the body.