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5. (7 marks) Yellow fever is a potentially fatal, mosquito-borne, viral disease that occurs in many countries in Africa, the Caribbean, and Central and South America - VCE - SSCE Biology - Question 5 - 2016 - Paper 1
Question 5
5. (7 marks) Yellow fever is a potentially fatal, mosquito-borne, viral disease that occurs in many countries in Africa, the Caribbean, and Central and South Ameri... show full transcript
Worked Solution & Example Answer:5. (7 marks) Yellow fever is a potentially fatal, mosquito-borne, viral disease that occurs in many countries in Africa, the Caribbean, and Central and South America - VCE - SSCE Biology - Question 5 - 2016 - Paper 1
Step 1
a. What is a vaccine?
Answer
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease. It typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. Vaccination stimulates the body's immune system to recognize the agent as foreign, destroy it, and 'remember' it, enabling the immune system to more easily recognize and destroy any of these microorganisms that it encounters in the future.
Step 2
b. Why is this time frame recommended?
Answer
The time frame of approximately two to four weeks is recommended for vaccination to allow sufficient time for the immune system to generate a robust response. During this period, the body produces specific antibodies and memory cells that are essential in mounting an effective immune response upon exposure to the actual pathogen. This preparation helps ensure the traveler is adequately protected when arriving in areas where yellow fever is prevalent.
Step 3
c. Name two different cell types that would be important in providing lifelong immunity and explain the role of each in providing lifelong immunity.
Answer
Name of cell type 1: T memory cells
Role: T memory cells survive for many years and proliferate rapidly into T helper (Th) and T cytotoxic (Tc) cells when the body is exposed to a pathogen for the second time. This results in a faster and more efficient immune response against the pathogen due to the body's prior exposure.
Name of cell type 2: B memory cells
Role: B memory cells will rapidly divide and form new antibody-producing plasma cells that are crucial for neutralizing pathogens and preventing reinfection. They act as a long-term repository of information regarding previous infections, enabling a swift and effective immune response.