"Microbiology/Immunology Antibody Structure & Function" SANA

Question 1

Which immunoglobin class is the heaviest?

Answer 1

IgM

Question 2

Which Immunoglobin is primarily responsible for the neutralization and protection against foreign bodies?

Answer 2

IgG

Question 3

IgM is often found as a ______ (organization)

Answer 3

Pentamer

Question 4

True or false? The light chains and heavy chains are identical to each other

Answer 4

False, they are different but one light chain in an antibody is identical to another light chain in an antibody (same for heavy chains)

Question 5

Where is IgA usually found?

Answer 5

In mucus membranes because it can transport across the epithelium

Question 6

Which immunoglobin is usually responsible for allergic reactions?

Answer 6

IgE

Question 7

IgE is responsible for the sensitization of ______

Answer 7

Mast cells

Question 8

Which antibodies does the fetus get directly from its mother?

Answer 8

IgG because they can transport across the placenta

Question 9

Which antibodies can diffuse into extravascular sites?

Answer 9

IgG

Question 10

Which immunoglobin class is the most stable? What is its half life in serum?

Answer 10

IgG; about 3 weeks

Question 11

True or false? IgG can directly kill a bacteria without a complement system.

Answer 11

False: IgG does not directly kill bacteria alone, it binds to it and, in the presence of a complement system, can kill it.

Question 12

How do natural killer cells use antibodies to target a cell?

Answer 12

Using antibody dependent cellular cytotoxicity where antibodies direct the NK cell to the target

Question 13

IgG can cause the clumping of bacteria. What is this called?

Answer 13

Agglutination

Question 14

Why can’t IgM aid in opsonization without the help of a complement system?

Answer 14

Because immune cells don’t have IgM receptors

Question 15

Which immunoglobin is crucial in EARLY immune response?

Answer 15

IgM, its found as antigen receptors on naive B-lymphocytes.

Question 16

What is holding the IgM pentamer together?

Answer 16

The J chain

Question 17

IgA is found mostly as ____

Answer 17

Dimers

Question 18

What is a secretory piece?

Answer 18

A protein that wraps around the IgA molecule as it passes through the epithelial cell and keeps it from being hydrolyzed.

Question 19

In what secretions is the IgA usually found?

Answer 19

Mother’s milk, saliva, gut secretions

Question 20

Where is the variable region found once the antibody has been cleaved? In the Fab region or the Fc region?

Answer 20

The Fab region

Question 21

Why does the Fc region crystallize and not the Fab region?

Answer 21

The Fc region does not have a variable region and the structures can thus form crystals as they are constant to each other.

Question 22

On which portion of the variable region of the antibody do the antigen bind?

Answer 22

The hypervariable region, which provides specific complementarity to the specific antigen.