What is biochemistry, and how it does differ from the fields of genetics, biology, chemistry, and molecular biology?

Biochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level.
Biology is the science that studys living organisms. It examines the structure, function, growth, origin,evolution,distribution and classification of all living things. Chemistry  is the study of matter and energy and the interactions between them. It tends to focus on the properties of substances and the interactions between different types of matter.
Biochemistry is both a life science and a chemical science. It explores the chemistry of living organisms and the molecular basis for the changes occurring inliving cells. It uses the methods of chemistry.
Molecular biology tends to deal with the molecular manipulation of DNA study and understands genes and their functions. It is a branch of biology that deals with the molecular basis of biological activity.. This field is related to biochemistry as well. It mainly concernes with understanding the interaction between types of DNA, RNA, and protein synthesis.
Genetics is the study of the effect of genetic differences on organisms. It includes a greater amount of theory and it analyses the inheritance of genes.


ref work


William A. Denny, ACS publications: Biochemistry