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a. Name one natural feature of the body that acts as a first line of defence when a person comes in contact with a pathogen - VCE - SSCE Biology - Question 8 - 2007 - Paper 1
Question 8
a. Name one natural feature of the body that acts as a first line of defence when a person comes in contact with a pathogen. b. Describe the role of interferons. ... show full transcript
Worked Solution & Example Answer:a. Name one natural feature of the body that acts as a first line of defence when a person comes in contact with a pathogen - VCE - SSCE Biology - Question 8 - 2007 - Paper 1
Step 1
a. Name one natural feature of the body that acts as a first line of defence when a person comes in contact with a pathogen.
Answer
One natural feature of the body that acts as the first line of defense is the intact skin. The skin acts as a physical barrier, preventing pathogens from entering the body.
Step 2
b. Describe the role of interferons.
Answer
Interferons are proteins produced by cells infected with viruses. They play a crucial role in the immune response by signaling neighboring cells to enhance their antiviral defenses. This leads to increased resistance to infection and stimulates the production of antiviral proteins.
Step 3
c. In the design of the vaccine, what feature prevents the virus-like particles infecting cells and causing disease?
Answer
The vaccine is designed to include virus-like particles that lack nucleic acids. This prevents them from replicating and infecting cells, thereby ensuring that they stimulate an immune response without causing disease.
Step 4
d. What is the purpose of injecting some women with a saline solution?
Answer
Injecting some women with a saline solution serves as a control. It allows for comparison between the immune responses of those receiving the vaccine and those receiving no active components, ensuring that any observed immune response in the vaccine group can be attributed to the vaccine itself.
Step 5
e. Why does the antibody response increase with each vaccination?
Answer
The antibody response increases with each vaccination due to the process of immunological memory. With each dose, the immune system is exposed to the antigen, leading to a more robust and faster production of antibodies upon subsequent encounters, as memory B cells are activated.