Biology 102 FINAL

Which of the following is a difference between B cells and T cells?

One has a major role in antibody production, while the other has a major role in cytotoxicity.

Clonal selection is an explanation for how _____.

an antigen can provoke production of high levels of specific antibodies

If a patient is missing B and T cells, what would be absent from the immune response

memory

Lymphocytes mature in the _____. I) spleen II) thymus III) bone marrow

only II and III

What major advantage is conveyed by having a system of adaptive immunity?

It enables a rapid defense against an antigen that has been previously encountered.

A newborn who is accidentally given a drug that destroys the thymus would most likely _____.

be unable to differentiate and mature T cells

An otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick. The EBV antigen fragments will be presented by the virus-infected cells along with _____.

class I MHC molecules

An antigen _____

is a foreign molecule that evokes a specific response by a lymphocyte

Vaccination increases the number of _____.

lymphocytes with receptors that can bind to the pathogen

An immunoglobulin (Ig) molecule, of whatever class, with regions symbolized as C or V, H or L, has a light chain made up of _____.

one C region and one V region.

Which of the following statements are fundamental to the clonal-selection theory of how the adaptive immune system functions? I) Each lymphocyte has a unique membrane receptor that recognizes one antigen. II) When the lymphocyte binds an antigen, it is activated and begins dividing to form many identical copies of itself. III) Cloned lymphocytes have slight differences and are selected by the spleen for removal if they do not bind an antigen. IV) Cloned cells descend from an activated lymphocyte and persist even after the pathogen is eliminated.

only I, II, and IV

Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by a(n)_____

recombinase

The fact that there are about a million different antigen receptors possible in human B cells is based on _____.

recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells

Clonal selection and differentiation of B cells activated by antigen exposure leads to the production of _____.

short-lived plasma cells that secrete antibodies for the antigen

Immunological memory accounts for _____.

the ancient observation that someone who had recovered from the plague could safely care for those newly diseased.