Download AP Biology: Immune System WebQuest

Name: ____________________________________________________ Date: _____ Period: ____
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AP Biology: Immune System WebQuest
In this webquest, you will explore how the human body protects itself from invaders through three lines of defense. You
will be going to different websites to see videos, animations, and images and to read explanatory text that will give you
information that you will need in order to answer a series of questions about the immune system and how it works.
Type your answers to the following questions. Be sure to write in your own words and use complete sentences.
Perform a google search to answer the following 3 questions:
1. Define pathogen and list 4 types of pathogens.
Disease-causing organisms such as bacteria, viruses, fungi and parasites that can trigger a specific immune
response
2. Define antigen and give 3 examples of common antigens.
Any substance that stimulates a specific immune response. Bacteria, fungi, pollen grains, environmental
chemicals, certain foods, bee venom.
3. What is the purpose of the first line of defense? Is it general or specific?
These are a combination of external physical and chemical barriers that prevent all types of foreign agents from
penetrating the outer layer of the body. This is a general defense.
Watch the first 2:40 of the following video that shows gives an overview of how the body protects
itself from microbes and explains how the first and second lines of defense work.
http://www.youtube.com/watch?v=IWMJIMzsEMg
4. What are the body’s three defenses? How do they differ from each other?
First line: keep pathogens out (general, nonspecific defense).
Second line: pathogens that have entered body are fought by nonspecific defenses (NK cells, neutrophils,
macrophages, inflammatory response, histamines, complement, interferons)
Third line: immune system that battles specific microbes
5. How do the skin, sweat glands, mucus membranes, and acids in the stomach protect the body? To what level of
defense do these belong?
The skin, sweat glands, mucus membranes and stomach acids are all parts of the first line of defense, which all
prevent pathogens from entering the body. The skin creates a barrier against pathogens using hard proteins on
its surface. The sweat glands produce a body fluid that contains acids and natural antibiotics (lysozymes) which
stop bacteria and fungi from growing. The mucus membranes coat the linings of the entrances to the digestive
and respiratory systems. The membranes secrete mucus, a sticky substance that traps bacteria and other foreign
particles. Mucus also contains antibacterial enzymes that break down bacterial cell walls. Under the mucus
layer, there are cilia that sweep the mucus & foreign substances out of the body. Acids in the stomach kill
bacteria and other microorganisms.
6. What are three nonspecific internal defenses?
Inflammatory response, phagocytic cells, natural killer cells, fever
Watch the following video about natural killer cells. NOTE: You need to have YouTube open before clicking
on this link at school.
http://www.youtube.com/watch?v=HNP1EAYLhOs
Name: ____________________________________________________ Date: _____ Period: ____
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7. What are natural killer cells? What kinds of cells do they attack? How do they work? Is this a specific or
nonspecific defense?
Natural killer cells are nonspecific cells that circulate through the body and detect the abnormal array of surface
proteins characteristic of virus infected cells and cancerous cells. They release chemicals like perforin that lead
to cell death, inhibiting spread of the virus or cancer.
Watch the following podcast about the inflammatory response. NOTE: You need to have YouTube open
before clicking on this link at school.
http://www.youtube.com/watch?feature=fvwp&v=_bNN95sA6-8&NR=1
8. When does the inflammatory response occur? What are three signs of the inflammatory response?
When the skin is cut/injured. Redness, swelling, pus are signs of the inflammatory response.
9. What cells release histamine? How does the body respond to the release of histamine?
Damaged mast cells release histamine. Histamine causes arterioles to open and venules to narrow, which leads
to increased blood flow to the area. (Thus, redness and heat). Capillaries dilate and become leaky to platelets
and clotting factors.
10. How do platelets play a role in the inflammatory response?
Platelets and clotting factors will migrate to site of injury from capillaries. These will help close wound and
confine infectious agent to the wound site.
Watch the Bozeman podcast on The Immune System and answer the following questions.
http://www.youtube.com/watch?v=z3M0vU3Dv8E
NOTE: You need to have YouTube open before clicking on this link at school. If you had to search for this
podcast from YouTube, make sure you open “THE IMMUNE SYSTEM” and not just “IMMUNE SYSTEM.”
11. Describe what a virus, such as small pox, does in a human body. Virus gains entry into cells, use cell’s machinery
to make thousands of copies of itself and then kills cell and spread to infect other cells.
12. Mr. Anderson compares the defense of a castle to the defense of a human body. Complete the following chart
of that analogy. Mention three specific parts of the castle and the parts of the human body that correspond and
explain why they are similar.
Part of Castle
Part of Human Body
Explanation of why they are similar
wall/ moat
skin
Creates a barrier from outside (enemies)
Soldiers
inflammation
Attack when enemies enter through the barrier
spies
Specific immune response
Attacks specific targets
b-cells and t-cells
13. What are 4 ways that skin defends the body from infection? Is this a specific or a nonspecific defense?
Barrier of cells prevents pathogens from crossing through skin
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Low pH that inhibits or stops bacterial or fungal growth
Chemicals that disrupt viruses
Normal bacterial flora that crowd out pathogenic bacteria.
This is a nonspecific defense.
What is an “antigen”? An antigen is an invader.
How was the name “antigen” derived? Carefully draw an antibody and its antigen. Explain how an antibody
works to protect the body and explain how the structure of an antibody relates to its function.
Antigen means antibody generating substance. An antibody is a special Y shaped protein that is secreted by
specific lymphocytes and has a specific molecular shape that matches the molecular shape of an antigen. The
shape of the antibody gives it the ability to combine with and inactivate the antigen.
Antibodies mark the antigen so macrophages can find the antigen and prevent it from functioning properly.
Explain what it means for a person to have specific immunity to an antigen.
That person has the ability to produce antibodies specific to those antigens.
What are lymphocytes and what are the two major classes of lymphocytes?
A type of white blood cell. B and T are the two major classes.
In what part of the body are each type created?
B in the bone marrow responsible to humoral response. T mature in the thymus & responsible for cell-mediated
response.
Explain the humoral response. What causes this type of response? What kinds of cells and chemicals are
involved? Explain the functions of each of these cells and chemicals.
Viruses or bacteria free in the fluids in the body. B cells produce antibodies specific to that antigen, and make
memory cells so you have long- term protection.
Explain the cell-mediated response. What causes this type of response? What kinds of cells are involved?
Explain the functions of each of these cells.
T cells become activated and become killer T cells that dock with infected cells and cancer cells and then kill
those cells.
What is the role of a macrophage in the immune response?
A Macrophage eats antigens, chops up and presents pieces of the antigen on surface within the MHCII. T-helper
cell will dock with macrophage and recognize the shape of the presented antigen.
What specific kind of cell is attacked by HIV? Why is this so damaging to the immune system? Be specific.
Helper T cells are attacked by HIV. T- Helper cells tell the shape of the antigen to the B cells and activate them,
activate macrophages, activate killer T cells to kill virus–infected or cancer cells.
Give three examples of cell-cell communication in the immune response to an antigen.
Macrophage tells Helper T cells the shape of the antigen and activates the helper T cell by releasing cytokines.
Helper T cell activates B cells and killer T cells.
Explain how a person can be infected by a disease pathogen and not know it.
If a person already has memory cells against that pathogen, then the immune response (production of
antibodies and killer T cells) is so fast that the body does not know that it was infected before the immune
system clears the infection.
How do viruses and bacteria get around the immune system?
They mutate and have so many different types that body does not have antibodies that work against that
specific antigen.
Do a google search to answer question #26.
Name: ____________________________________________________ Date: _____ Period: ____
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26. Distinguish between self and non-self antigens.
Self antigens are surface marker proteins on the individual cells of multicellular organisms that the body’s
immune system recognizes. Non-self antigens are markers on cells and tissues which may have entered the
organism -eg. transplant, virus, bacteria, and which the body's immune system recognizes as foreign and as a
result will initiate an immune response.
Watch the video on the development of vaccines.
http://www.pbs.org/wgbh/rxforsurvival/series/video/d_pol1_dis_vaccine.html
27. How did Jenner use cow pox to protect individuals from small pox? He developed a vaccine for the small pox
virus by inoculating a young boy with cow pox. The viruses were so similar that the immune response to the
cow pox virus gave the boy immunity to the small pox virus.
28. How did Louis Pasteur cure the boy who was bitten by a rabid dog?
He developed his rabies vaccine by growing the rabies virus in rabbits, then drying the affected nerve tissue to
weaken the virus. He then injected the vaccine into the boy that had been bitten. The boy survived and avoided
contracting rabies.
Go to the following website and work through the click and learn.
http://www.hhmi.org/biointeractive/disease/immunology_primer/01.html
29. Watch the page 3 video and contrast B cells, Helper T cells, Cytotoxic T cells, and antigen presenting
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Watch the page 4 video and explain the humoral response.
Summarize the page 5 video.
How do macrophages participate in adaptive immunity?
What is a TCR and how are they similar to antibodies?
Watch the video on page 8 and describe how helper T cells work.
Watch the page 9 video and explain how cytotoxic T cells work.
Contrast MHC class 1 and 2 presentation systems.