phelanphys3e

26.5–26.10: Specific immunity develops after exposure to pathogens.

The memory of the specific division of the immune system can confer immunity, a state of long-term protection against a specific pathogen.

Question 26.16

Why don’t people develop immunity to the common cold?

a) Actually, many people do develop immunity to the common cold and get sick only from bacterial infections.
b) There are at least 200 different viruses that can cause the common cold, and they change over time.
c) Only non-specific immunity helps individuals fight the common cold; specific immunity is not an effective defense against viruses.
d) The rhinovirus that causes the common cold has no surface antigens and so can move through the body without being detected.
e) The pathogen that causes the common cold attacks and kills memory cells, continually “erasing” the immune system’s memory of it.

Question 26.17

Antibodies:

a) are produced by helper B cells.
b) are produced by helper T cells.
c) are produced by B cells bound by a specific antigen.
d) are produced by plasma cells.
e) are made in the bone marrow.

Question 26.18

The polypeptides that make up the structure of an antibody consist of:

a) two heavy chains and two light chains, shaped like a “Y,” with a lower constant region and an upper variable region.
b) two heavy chains and two light chains, shaped like a “Y,” with an upper constant region and a lower variable region.
c) one heavy chain and one light chain, shaped like a “Y,” with a lower constant region and an upper variable region.
d) one heavy chain and one light chain, shaped like a “Y,” with an upper constant region and a lower variable region.
e) Both b) and d) can be correct, depending on the type of antibody

Question 26.19

Which of the following is not a function of helper T cells?

a) They stimulate B cells to proliferate and produce antibodies.
b) They activate cytotoxic T cells.
c) They stimulate B cells to secrete cytokines.
d) They recognize antigens presented on macrophage surfaces.
e) All of the above are functions of helper T cells.

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Question 26.20

Autoimmunity is:

a) one of three lines of defense in the vertebrate immune system.
b) responsible for muscular dystrophy, which occurs when immune cells destroy the myelin sheath, reducing motor control and balance.
c) the culprit in rheumatoid arthritis, which occurs when immune attack on the linings of joints causes inflammation.
d) a consequence of a body’s inability to produce antigens, leading it to attack its own cells as if they were pathogens.
e) All of the above statements about autoimmunity are correct.

Question 26.21

As the human immunodeficiency virus (HIV) begins to kill the host’s, the host’s immune system begins to fail.

a) thymus cells
b) spleen cells
c) red blood cells
d) white blood cells
e) liver cells

Question 26.22

Hay fever affects millions of individuals every year and is caused by an allergic reaction to pollen. Which of the following is not a step of the process in which a pollen grain causes an allergic reaction in an individual?

a) Mast cells burst when they encounter the pollen during the initial exposure, releasing histamine and other chemicals.
b) During the first exposure, B cells are activated by the pollen and differentiate into antibody-secreting plasma cells.
c) During the second exposure, the pollen grains are recognized by previously created antibodies on mast cells.
d) A type of antibody, specific to the pollen grain, is produced during the initial attack, and these antibodies adhere to mast cells, where they remain.
e) Histamine and other allergen chemicals cause itchy eyes and a runny nose.