6.2.4 - Antigen & Antibodies

Question 1

Describe Antigens
(4 Points)

Answer 1

~ Molecules or molecular structures that are recognized by the immune system, specifically by antibodies, B cells, or T cells.

~ Are found on the cell surface membranes, bacterial walls and surfaces of viruses.

~ They can either by self or non-self.

~ Antigen presenting cells activate the specific immune response.

Question 2

Describe Self Antigens
(2 Points)

Answer 2

~ Produced by the organisms own body cells.

~ Do not stimulate an immune response.

Question 3

Describe Non-Self Antigens
(2 Points)

Answer 3

~ Are antigens not produced by the organisms own body cells.

~ They do stimulate an immune response.

Question 4

What Happens With Regards To Antigens After Pathogens Are Engulfed By Phagocytes?

Answer 4

Phagocytes then transfer the antigens of the digested pathogen to their cell surface membrane, becoming antigen presenting cells.

Question 5

What Can Antibodies Be Referred To As?

Answer 5

Immunoglobulins.

Question 6

Describe The Antibody Structure
(3 Points)

Answer 6

~ There are 4 polypeptide chains attached by disulfide bonds.
-> 2 heavy chains and 2 light chains.
-> The heavy chains are long and the light chains are short.
~ Each polypeptide chain has a constant region and a variable region.
~ At the end of the variable region is a site called the antigen binding site.

Question 7

What Do Disulfide Bonds Do?

Answer 7

Holds the polypeptide chain together.

Question 8

What Is The Constant Region?
(2 Points)

Answer 8

~ Always stays the same.
~ Allows binding to receptors on immune cells.

Question 9

What Is The Variable Region?
(3 Points)

Answer 9

~ Different for each antibody.
~ Complementary to a specific antigen.
~ Is where an antigen-antibody complex is formed.

Question 10

What Is The Antigen Binding Site?

Answer 10

Varies greatly, giving the antibody its specificity for binding to antigens.

Question 11

What Is The Hinge Region?

Answer 11

Gives the antibody flexibility, so it is easier to bind to the pathogen.

Question 12

Antibodies Can Either Be …?

Answer 12

~ Membrane bound.
~ Secreted directly into the blood.

Question 13

Describe Membrane Bound Antibodies
(2 Points)

Answer 13

~ Attached to the surface of lymphocytes.
~ Have an extra section of polypeptide chain within their heavy chains, which forms the attachment to lymphocytes.

Question 14

What Does Splicing Do?

Answer 14

Removes non-coding sections of mRNA called introns.

Question 15

What Does Alternative Splicing Do?

Answer 15

Removes coding sections called exons.

Question 16

What Is The Antibodies Function?
(3 Points)

Answer 16

~ Disable pathogens.
~ Act as anti-toxins.
~ Agglutination.

Question 17

What Is Agglutination?
(2 Points)

Answer 17

~ Causing pathogens to clump together.
~ Easier for antigens to engluf the pathogen.