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Human immunodeficiency virus (HIV) is a pathogen - AQA - GCSE Biology - Question 7 - 2022 - Paper 1
Question 7
Human immunodeficiency virus (HIV) is a pathogen. Give one way HIV can spread from one person to another person. Table 8 shows information about new cases of HIV d... show full transcript
Worked Solution & Example Answer:Human immunodeficiency virus (HIV) is a pathogen - AQA - GCSE Biology - Question 7 - 2022 - Paper 1
Step 1
Step 2
Describe the trends shown in Table 8 between 2010 and 2018.
Answer
The data indicates that the number of new HIV cases diagnosed in women shows a general decline from 2010 to 2018, starting from 376 cases in 2010, peaking at 397 in 2014, and then decreasing to 242 cases in 2018. In contrast, the number of new cases in men initially increased from 2266 in 2010, reaching a peak of 2370 in 2014, before declining to 1288 by 2018.
Step 3
Suggest one reason for the change in the number of new HIV cases between 2014 and 2018.
Answer
One reason for the decline in new HIV cases from 2014 to 2018 could be the increased awareness and availability of preventative measures, such as PrEP (pre-exposure prophylaxis) and better access to testing and treatment.
Step 4
Calculate the ratio of new cases of HIV in women to new cases of HIV in men in 2018.
Answer
In 2018, there were 242 new cases in women and 1288 in men. The ratio of new cases of HIV in women to men can be calculated as follows:
Thus, the ratio to 3 significant figures is:
Ratio (3 significant figures) = 0.188 : 1
Step 5
Suggest how the data could be presented differently so that a more valid comparison can be made.
Answer
The data could be presented as a percentage of the total new cases in each year for both men and women rather than just raw numbers. This would allow for a more valid comparison between the two groups, especially considering the difference in population sizes.
Step 6
Explain how a vaccine for HIV could work to prevent a person developing HIV infection.
Answer
A vaccine for HIV would work by introducing inactive or weakened forms of the virus into the body, prompting the immune system to produce antibodies. This prepares the immune system to recognize and combat the active virus if exposed in the future, thereby preventing infection.
Step 7
Describe how the monoclonal antibody for HIV can be produced.
Answer
Monoclonal antibodies for HIV are produced by first injecting a specific part of the HIV virus into a mouse. The mouse's immune system generates lymphocytes that produce antibodies against the virus. These lymphocytes are then fused with a hybridoma cell line to create a hybridoma, which multiplies and produces large quantities of the specific antibodies.
Step 8
Suggest how the monoclonal antibody for HIV helps to prevent a person infected with HIV developing AIDS.
Answer
The monoclonal antibody for HIV is designed to be complementary and specific to HIV antigens. When introduced into the body, it binds to the virus, preventing it from entering human cells and thus inhibiting viral replication. This action can delay or prevent the progression of HIV infection to AIDS.