Writing a good essay on the subject of Biophysics would inevitably involve a literature research in the recent peer-reviewed publications. Appropriate publication databases should be searched for relevant articles and reviews. Usual web search is unlikely to produce a comprehensive overview of existing body of knowledge since these days many scientific articles are simply not available in the free access.
Clear well-defined structure with logical and coherent flow of information is critically important. Your essay should tell a “story”, which would include basic well-established facts, recent findings (which might, on some occasions, contradict the existing dogmas), their interpretations and relevant scientific theories (either old or newly formulated), gaps in knowledge and potential future research directions needed to fill these gaps. In the essay on biophysical subject, it is particularly important to show the connections between the physical properties of the system in question and its biological structure and functions.
Reviewing up-to-date information would help to demonstrate not only your ability to learn the things taught at the classes but also to research and interpret new data. The latter is the most important skill for any independent researcher and something that, in the short terms, would bring you excellent marks.
Together with molecular and cell biology, biophysics helped to describe exactly which mechanisms are involved in the functioning of biological systems such as cells, tissues and organs in the normal circumstances and in the pathology. In conjunction with biotechnology and nanoscience, biophysics helps to explain and exploit the behaviour of biological systems at microscopic level. Keeping in mind this interdisciplinary nature of biophysics is important when you write your essay. Connecting physical data and theories with molecular, chemical and cellular information on the functions and properties of the biological systems adds to the value of your essay tremendously.
Research data and examples selected for essay should follow the logics of your essay. They should be not just relevant, but arranged in an order that helps to illustrate the right points at the right time. This would make the essay easily readable and understandable. Ability to communicate your thought clearly is always one of the points your essay will be marked for.
Obviously, the structure, depth and complexity of essay depend on the particular task at hands. The requirements for short undergraduate work and postgraduate dissertation are very different. But the major “selling” points mentioned above are always highly appreciated.