Is it possible to cross over from chemistry to biology? I'm currently a chemistry major. However, I am more interested in the life science and want to be a molecular biologist in the future. However it is too late to change my degree to biology so I am wondering how to cross over into biology with my chemistry degree and whether is it possible for me to be a molecular biologist in the future? Will my chemistry degree be useful in helping me to become a biologist? Is there any relations between chemistry and biology?
I am a theoretical physicist reconverted to biology (bioinformatics) in his masters. I am sitting next to computer scientists, mathematicians, chemists... all working on life sciences.

Biology is a very complex subject. Most of the concepts are easy, but there are many devils in the details. Ergo, it is very suitable for multidisciplinary work, where people from different branches can contribute with solutions from their own field.

Focusing on your question, depending on your set of skills, you have several options: biochemistry, wet lab, computational chemistry oriented to biomolecules... You can probably swing by the molecular biology department and ask what kind of problems they would need a chemist for; and perhaps ask if they are willing to take you on board for an undergaduate project.