part 3:

Question 1

What are the cells involved in the adaptive immune response?

Answer 1

• B Cell: produce and secrete antibodies that target extracellular pathogens.
• Cytotoxic T cells: target and kill infected cells to limit the ability of pathogens to reproduce.
• ## Helper T cells: necessary for the activation of the other cells.

Question 2

What is the basic function of the adaptive immune response?

Answer 2

• these are lymphocytes that will become activated in response to exposure to a specific pathogen and then take a very specific response.

Question 3

Where are T & B cells born?

Answer 3

Bone marrow

Question 4

Where do the B cell precursors remain?

Answer 4

Bone Marrow

Question 5

Where do the T cell precursors remain?

Answer 5

They mature in the thymus and then can circulate the body in bloody, but primarily remain in the lymphatic system.

Question 6

What is an antigen?

Answer 6

Any molecule that is recognized by your lymphocytes (B and T cells.).

Question 7

What is an immunogen?

Answer 7

• an antigen that activates a T or B cell.

Question 8

What are the two different branches of the adaptive response and what represents each one?

Answer 8

• ## Humoral response is carried out by the B-Cells: B- cells secrete antibodies into the blood stream, interstitial and lymphatic fluid that bind to extra cellular antigens before they have infected a cell.
• Cell mediated response is carried out by T cells:
  T cells surveil the body looking for cells that have been infected by pathogens carrying a specific antigen and then will kill it

Question 9

How are helper T cells involved in both branches of the adaptive response?

Answer 9

• They assist the activation of cytotoxic T cells.

Question 10

How do B cells and T cells recognize specific antigens?

Answer 10

• They have receptors on their surface called B cell and T cell receptors, which is what the recognizes and directly binds to the antigen in the environment.

Question 11

Describe the B-Cell receptor?

Answer 11

• It is shaped like a Y
• it has two identical arms, composed of a half chain and light chain.
• Each arm serves as an antigen binding site, which means the will bind to the same type of antigen.
• transmembrane protein anchored in the cell membrane.

Question 12

Describe the T-Cell receptor?

Answer 12

• It is similar in composition to the B-Cell receptor.
• It can only bind to one antigen at a time.
• one arm composed of an alpha and beta chain.
• transmembrane protein.

Question 13

What is important to realize regarding the protein structure of both the B and T cell receptors.

Answer 13

• they are proteins composed of multiple sub-units, each subunit is composed by a different gene.
  EX: the b cell receptor contains heavy and light chains, each of which is encoded for by a different gene.

Question 14

What is the difference between an antigen and an epitope?

Answer 14

• a molecule that binds to a T or B cell receptor is an antigen.
• the specific site on the antigen where the receptor is bond is the epitope.

Question 15

What is it about B cell and T cell receptors that allow it to bind to a particular epitope?

Answer 15

• ## In lecture he focuses on the B-cell receptor,
• the light chains are encoded by one gene and the heavy chains are encoded by anther.
• On both the heavy and the light chain, if you were to dived the chain into to two.. the second half is referred to as the variable region. These are areas on the receptor that will be different in every single cell.
• ## The areas that remain the same which is everywhere besides the variable region is known as the constant region.
• Each B-cell, makes one particular type of B-cell receptor that will recognize one specific kind of epitope.
• ## Likewise with the T cells.
• involves a process called DNA recombination.
  occurs in the embryonic development of the B cell and T cell precursors.
• this all results in a massive variety of very specific options that can be seen in both heavy, light, and alpha/beta chains

Question 16

Describe the process of DNA recombination?

Answer 16

-involves a process called DNA recombination.
occurs in the embryonic development of the B cell and T cell precursors.
—————————————————————————-
- in the light chain for example, there are three segments: variable, joining, and constant.
- in the variable region there are 40 segments, in the joining region their are 5 different segments, and in the constant region there is just one segment.
- —————————————————————————-
- within the heavy chain region of the DNA:
- there is 51 variable segments, 27 diversity segments,, 5 joining segments, and one constant segment.
——————————————————————————
- When a B cell is developing it is going to remove all but one variable segment and joining segment from the light chain
&
- it is going to remove all but one variable, diversity, and joining segment in the heavy chain
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- same thing happens for the heavy chain.