Imagine that you are trying to explain how the immune system functions to a chil
ID: 301302 • Letter: I
Question
Imagine that you are trying to explain how the immune system functions to a child. You want to describe it in terms the child can understand, so you invent a story in which the functioning of the immune system is analogous to the defense of a space station. The story that you use is written below. Please fill in each blank with the answer that best completes each statement. Each answer is used only once. “Imagine that your body is a space station named Homo sapiens. There are many evil aliens that can invade and destroy the space station. These aliens are called [a]. Surrounding the space station is a protective shield, which can often prevent the aliens from invading the space station. Because the shield helps to protect the space station against all types of aliens, it is called the [b]. Sometimes, however, the aliens penetrate the protective shield. There are soldiers living in the space station that can protect it from the aliens that get past the protective shield. These soldiers “lock on to” an alien before it reaches the space station and neutralize it. Only certain soldiers can lock on to and neutralize a particular type of alien. For example, only soldiers with fire extinguishers can neutralize aliens that shoot fire and only soldiers with shields can neutralize aliens with swords. This is called the [c], because only a certain type of soldier can neutralize each type of alien. Soldiers recognize each other because they all wear the same uniform, the [d]. There are different groups of soldiers. One group of soldiers are trash collectors. These soldiers, called [e], swallow up debris in the space station and hold up pieces of the debris for other soldiers to see. Another group of solders, called [f], produce [g], which attach to the aliens and keep them from entering rooms in the space station. The soldiers in a third group are called the [h]. These soldiers, with the assistance of [i] soldiers, “blow-up” aliens that have invaded rooms in the space station, destroying the rooms in the process. When a soldier locks on to an alien, the soldier makes many duplicate copies of itself, called clones. However, this takes time. Sometimes, the aliens can cause great damage, or even destroy the space station before there are enough soldiers to neutralize them. Therefore, the Intergalactic Physician may [j] the space station before the aliens arrive to prevent them from doing any damage or destruction. This is done either by sending dead, [k] aliens, living, [l] aliens that were captured and disarmed (have no weapons), or pieces of dead aliens called [m] aliens to the space station. The soldiers on the space station lock on to these aliens and duplicate themselves. Then, when the ‘real’ aliens, with real weapons, try to invade the space station, there are already many soldiers ready to neutralize them and no damage is done to the space station. Even after the attack is over, a few soldiers remain on “combat alert” and are ready should a second invasion occur. These soldiers are called [n]. In cases of great emergency, when the aliens have already invaded the space station and before the soldiers can duplicate in great enough numbers to neutralize them, the Intergalactic Physician may send soldiers from other space stations to help the one in distress. These are called [o] soldiers, and their function is to neutralize as many aliens as possible until the soldiers that live on the invaded space station can duplicate and protect the space station themselves. Occasionally, some solders become confused, and begin attacking parts of the space station that remind them of themselves. This is called [p]." adaptive immune response • IgG (antiserum or antitoxin) • antibodies • inactivated • antigens • innate immune response • attenuated • macrophages • autoimmunity • memory B and T cells • B cells • MHC • cytotoxic (CD8) T cells • sub-unit • helper (CD4) T cells • vaccinate
Explanation / Answer
(a) antigens
(b) innate immune response
(c) adaptive immune response
(d) IgG (antiserum or antitoxin)
(e) macrophages
(f) B cells
(g) antibodies
(h) cytotoxic (CD8) T cells
(i) MHC
(j) vaccinate
(k) inactivated
(l) attenuated
(m) sub-unit
(n) memory B and T cells
(o) helper (CD4) T cells
(p) autoimmunity