2 x 25 min interviews over 2 days
Pre-reading article, chemistry, personal statement, and genetics
Mock interview and read books
Don't be afraid to ask questions
Remember this advice isn't official. There is no guarantee it will reflect your experience because university applications can change between years. Check the official Cambridge and Oxford websites for more accurate information on this year's application format and the required tests.
Also, someone else's experience may not reflect your own. Most interviews are more like conversations than tests and like, any conversation, they are quite interactive.
Test taken: None
Number of interviews: 2
Time between interviews: A day
Length of interviews: Around 25 minutes
Online interview: No
We were told at a meeting the evening before that we would have pre-reading for the first interview. This involved a 30 minute slot reading through a magazine article, not everyone got the same article. So, part of the first interview was talking through what we learned from the article. Then we discussed topics I talked about on my personal statement and I was asked to look at some microscope images and suggest what they were displaying. Both my interviewers were very relaxed which encouraged me to be more comfortable, especially once we finished with the pre-reading discussion which is what I was most worried about. The second interview was at a different college, and was more split into a genetics part and a chemistry part. This interview didn't bring up my personal statement at all, unlike the first one. For the genetics section, I was given a small problem sheet and they discussed each question with me, asking little questions as we worked through it. There was a bit of maths here but not actual calculations, more suggesting how you would work it out. The chemistry section involved me drawing some molecules and also them giving me some molecules and discussing how they would interact with each other and different environments. The second interview felt a bit more formal as we were all sat round a table as opposed to one of my first interviewer's office. But, I could see that again both my interviewers were very friendly which helped me settle into the interview. They also were both understanding when I got flustered on a question and helped me get to the answer - this is because they prefer to see how you get to an understanding of a new problem rather than watching you struggle on your own and not get anywhere.
I had a mock interview at school which showed that I needed to be able to comfortably talk about everything I mentioned on my personal statement. I talked a lot about genetic diseases there and so I read Genome by Matt Ridley which was very helpful. I found a reading list on the website and so I bought a couple of the books - including Genome - but I did not thoroughly read them and there was no need to.
Remember that the interviewers are people themselves who want you to do well and understand things. Don't be afraid to ask questions yourself if you don't understand a word or how they phrased the question. Especially with biochemistry not being an A-level subject they understand that there may be some gaps in your knowledge and that at the time of the interview you may not have been taught everything at school. I would have a brief look at the specification and see what topics you haven't covered so you can say "oh we haven't looked at that yet" if they ask you about NMR for example, and they may ask you a different question. Also, if you know what college/colleges you are getting interviewed at I would see if you can figure out who may be interviewing you and look at what they research. This doesn't work all the time as they may just not ask you about a relevant topic or they may not be your interviewer.