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Scientists investigated the role of a protein called CENP-W in mitosis - AQA - A-Level Biology - Question 5 - 2018 - Paper 3
Question 5
Scientists investigated the role of a protein called CENP-W in mitosis. Their method involved cell fractionation and ultracentrifugation. The scientists began by ly... show full transcript
Worked Solution & Example Answer:Scientists investigated the role of a protein called CENP-W in mitosis - AQA - A-Level Biology - Question 5 - 2018 - Paper 3
Step 1
Suggest how the detergent releases CENP-W from cells.
Answer
The detergent disrupts the cell membrane, which is primarily composed of phospholipids. By dissolving the lipid bilayer, the detergent effectively lyses the cells, allowing the contents, including the protein CENP-W, to be released into the surrounding solution.
Step 2
Explain how ultracentrifugation separates CENP-W from other molecules.
Answer
Ultracentrifugation separates molecules based on their size and density. When the sample is spun at high speeds, larger and denser molecules sediment faster than smaller or less dense ones. CENP-W can thus be isolated by adjusting the centrifugation speed to differentiate it from other cellular components.
Step 3
Suggest how the siRNA produced these results.
Answer
The siRNA binds to and degrades the mRNA specific to CENP-W, preventing its translation into the corresponding protein. This results in a decrease in the amount of CENP-W protein observed in the electrophoresis results as compared to tubulin, which remains unaffected by the siRNA treatment.