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From time to time, local health agencies such as councils, health centres and doctors distribute information about recommended immunisation schedules for vaccination of Australian children and adults - VCE - SSCE Biology - Question 7 - 2004 - Paper 1
Question 7
From time to time, local health agencies such as councils, health centres and doctors distribute information about recommended immunisation schedules for vaccination... show full transcript
Worked Solution & Example Answer:From time to time, local health agencies such as councils, health centres and doctors distribute information about recommended immunisation schedules for vaccination of Australian children and adults - VCE - SSCE Biology - Question 7 - 2004 - Paper 1
Step 1
a. Explain why dead or attenuated cells are effective as a vaccine.
Answer
Dead or attenuated cells are effective as vaccines because they are recognized by the immune system as foreign substances. When introduced into the body, these altered cells stimulate an immune response without causing the disease. This response involves the activation of T cells and B cells, leading to the production of specific antibodies against the antigens present on the surface of the dead or attenuated cells.
Step 2
b. Explain how vaccination leads to the production of memory cells.
Answer
Vaccination leads to the production of memory cells through a process called clonal expansion. After vaccination, the antigens interact with B cells, triggering them to divide and reproduce extensively. Some of these cells differentiate into plasma cells that produce antibodies. Importantly, a subset of these B cells will become memory cells that remain in the body for years, allowing for a faster and more effective immune response upon subsequent exposures to the same antigen.
Step 3
c. Explain the likely source of antibodies a baby may have between the ages of 0 and 2 months.
Answer
The likely source of antibodies for a baby between the ages of 0 and 2 months is maternal antibodies. These antibodies are transferred from the mother to the baby during pregnancy through the placenta. Additionally, if the baby is breastfed, some maternal antibodies can also be passed through breast milk, providing passive immunity during the early stages of life.
Step 4
d. Draw a graph indicating the level of diphtheria antibodies you would expect in the baby from the age of 2 to 18 months.
Answer
The graph should show an initial rise in diphtheria antibodies following vaccinations at 2, 4, and 6 months, where peaks may occur after each injection. It should indicate a gradual decline in antibody levels after the initial peaks, illustrating the waning of maternal antibodies and the buildup of the baby’s own antibody response. From 12 months to 18 months, the antibody levels may stabilize or show a slight increase, depending on routine booster vaccinations.