Organisms have a variety of mechanisms to combat disease. Antibodies play an important role
in the body’s response to infection.
Figure 1 represents an antigen (AN tih jihn) and an antibody. An antigen is a substance that
typically includes proteins of disease-causing cells or parts of viruses. The antigens of the
bacteria are shown as darkened dots in Figure 1. Antigens will trigger an immune response,
causing the organism to respond to infection.
An antibody, represented by letter C, is a defensive protein produced by an organism upon
exposure to a specific antigen. The organism’s antibody can bind to the antigen. The point
where the antibody joins to the antigen is called the antigen-binding site, represented by letter
B. Antigen-binding sites allow an antibody to bind to two antigens. By attaching to antigens,
antibodies can form a large mass that will be consumed by phagocytes (cells that eat-up foreign
or old cells), destroying the pathogens.
In active immunity, the body produces its own antibodies against a particular antigen. In passive
immunity, a person is given antibodies obtained from the blood of either another person or an
animal. Active immunity is a type of immunity that may develop as a result of having had a
disease, and the disease rarely recurs. Passive immunity, on the other hand, is only temporary
and usually does not last for more than several weeks.
1.
What does letter B represent?
The letter B represents as stated in the paragraph 2 the antigen-binding site. It allows an antibody
to bind two antigens. This allows phagocytes to eat-up foreign cells.
2.
What does letter C represent?
Paragraph 2 says letter C is an antibody. An antibody is a defensive protein produced by an
organism upon exposure to a specific antigen. Letter C in the image looks like a Y.
3.
What kind of immunity is represented in Figure 1? Why?
The immunity represented in Figure 1 is cell-mediated immunity. This is because antígena are
cells and they respond to threats.
4.
Explain how an individual develops active immunity.
An individual develops active immunity when getting sick multiple times. After that they can
fight it because it is not a new disease.
5.
Describe the role antigen-binding sites play in an infection.
The role of antigen-binding sites play in an infection is to bind to foreign antigens.
6.
Describe passive immunity.
Passive immunity is when a person is given antibodies to a disease rather than producing them
through his or her own immune system.
7.
Explain how an individual develops passive immunity.
Passive immunity can occur naturally, such as when an infant receives a mother's antibodies through the
placenta or breast milk, or artificially, such as when a person receives antibodies in the form of an
injection (gamma globulin injection).