Biochemistry science fair projects are all about the chemistry required for life processes. They can look at enzymes, hormones and the chemicals that make up DNA. If you are interested in chemistry and in biology then this is a great subject to explore.
When you are ready to work on your science fair project you need to first find a topic to work with. To start with you will select a broad category subject like biochemistry. Then you will narrow down your options to a sub-topic of biochemistry like hormones or enzymes.
Once you have a sub-topic that you are interested in you can start conducting background research. This will help you to find an interesting angle to approach your topic from. For example, you may find a news story about how scientists used the DNA from two female and one male monkey to create a single fertilized egg in order to combat a sex linked trait that produced a serious physical disorder.
After you have an angle for your project you will want to come up with a final topic for your science fair project. This final topic will be very specific. It will identify two variables related to your topic and it will identify a possible relationship between the two.