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Hepatitis B is a life-threatening liver infection caused by the hepatitis B virus (HBV) - AQA - A-Level Biology - Question 7 - 2021 - Paper 1
Question 7
Hepatitis B is a life-threatening liver infection caused by the hepatitis B virus (HBV). Figure 7 shows the structure of HBV. Figure 7 HBV infects a liver cell. Th... show full transcript
Worked Solution & Example Answer:Hepatitis B is a life-threatening liver infection caused by the hepatitis B virus (HBV) - AQA - A-Level Biology - Question 7 - 2021 - Paper 1
Step 1
Use Figure 7 to calculate how many times larger in diameter this cell is than HBV.
Answer
To determine how many times larger the liver cell is compared to HBV, we first need to measure the diameter of HBV from Figure 7. Assuming the lipid layer of HBV measures approximately 40 nm (or 0.04 µm), we can use the formula:
ext{Ratio} = rac{ ext{Diameter of liver cell}}{ ext{Diameter of HBV}} = rac{25 ext{ µm}}{0.04 ext{ µm}} = 625.Thus, the liver cell is 625 times larger in diameter than HBV.
Step 2
Suggest why this increases uptake of RNAi molecules into cells.
Answer
The incorporation of RNAi molecules with lipids facilitates their entry into cells due to the lipid’s compatibility with the cell membrane, which consists of a phospholipid bilayer. This means that the RNAi lipid complexes can fuse with the membrane more effectively, promoting the uptake of these molecules into the cytoplasm.
Step 3
Evaluate the use of the two types of RNAi in treating hepatitis B in humans.
Answer
Both types of RNAi show potential in treating hepatitis B. They can effectively reduce the viral load. However, significant differences in their effectiveness may exist, as evidenced by the results from experiments. For instance, shRNA may lead to a 7.5% reduction compared to a control. Moreover, replication is decreased but not eliminated. It is worthy to note that, while both RNAi types are effective, the exact mechanisms and efficiency in humans are yet to be fully understood and require further investigation.
Some important points to consider include the implications of the observed differences, the necessity for human trials, and the importance of understanding side effects. Continuous research is needed to ascertain the long-term benefits and potential risks associated with both strategies.