Biology Personal Statement 例文Oxford, Cambridge & Imperial出願用

Reading about AlphaFold2's performance in CASP14 in 2020 made me think differently about proteins. A polypeptide starts as a linear sequence, yet folds into a structure precise enough to determine binding and catalysis. What interested me was not just that a system could predict that structure, but what the prediction implied biologically: if folding is so constrained by sequence, why can one substitution leave a protein looking almost unchanged while still altering its function? That question sent me back to tertiary structure and enzyme action. I began to look beyond textbook diagrams of hydrogen bonds, ionic interactions and disulfide bridges and think about the balance they create: proteins have to be stable enough to work, but flexible enough to change and interact. That is what makes biology worth studying at degree level for me. I want to study molecular biology in more depth, especially where sequence, structure and regulation produce behaviour that is patterned but not simple.

My studies have given that interest a more precise direction. In A-level biology, the induced-fit model made me think about enzymes as dynamic rather than rigid. Catalysis depends on geometry, but also on movement, charge and environment, which helped me connect protein structure to function more carefully. Because I kept returning to the gap between tidy molecular explanations and messy biological behaviour, I used my EPQ to investigate how pH and temperature affect catalase activity in potato extract. I prepared the extract, reacted it with hydrogen peroxide under buffered conditions, collected oxygen with a gas syringe and used the earliest part of each run to calculate initial reaction rates in Excel. My first results looked suspiciously neat. Repeating the trials showed why: small differences in preparation changed the apparent enzyme concentration enough to distort the pattern. Standardising the extraction volume, keeping samples on ice between runs and focusing on the initial rate improved the reliability of the data, but the project mattered most because it made the limits of simple explanations visible. That process made me more careful about what counts as evidence in biology.