Structural Biochemistry is the field of biochemistry that focuses mainly on the components, functions, and structures of molecules of cells within living organisms. It helps us understand cells through the theories of Chemistry and the laws of Physics. Structural biochemistry concentrates on the study of macromolecules (such as carbohydrates, proteins, polysaccharides, lipids), their monomeric units (amino acids, nucleic acids, nucleotides) and important reactions involving them.
Biochemistry is interlinked between Biology and Chemistry. Biology is the study of the cell’s interaction within its environment. Chemistry takes these interactions and breaks it down to the molecular level and provides information on how these events occur. Structure is defined by how a system is composed. It is the way in which parts are arranged or put together to form the whole. As a result, when these two subjects are fused, Biochemistry and Structure, the subject known as Structural Biochemistry comes into being. Structural Biochemistry forms the basis of the molecular parts via interactions such hydrogen, ionic, and covalent bonding that form the cellular structure.
Structural Biochemistry 
Structural biochemistry is a study of various macromolecules and how their structure is appropriate to their functions. Macromolecules studied in structural biochemistry courses that consists of proteins, carbohydrates, lipids, and nucleotides. They cover everything from the multitude of functions that proteins participate in (such as transport of molecules, cytoskeleton formation, and cell growth) to the building blocks of DNA, and even to the catalytic mechanism of different enzyme. All macromolecules in general contribute to the survival of humans, as well as to the composition of inanimate objects.
Another way to define structural biochemistry is by stating that it is the scientific study of the biochemical systems of life and living organisms; it is about biological molecules that construct chemical forms, and the close correlation between structure and function. Furthermore, biochemistry applies chemistry to biological studies at the cellular and molecular level. It surfaces as a distinct category at the turn of the 20th century, as scientists combined chemistry, physiology, and biology to explore the chemistry of living environments and systems. Using this field, biochemical scientists have been attempting to understand and explain the many chemical mechanisms and biological structures shared by living organisms, and to formulate some basic organizing principles shared by all forms of life as well.
Today, biochemistry is considered as the study of life in its chemical processes; the study of both a life science and a chemical science. It investigates the chemistry of living organisms and the molecular basis for the alteration happening in the living cells. It uses the schemes of Chemistry, Physics, molecular biology and immunology to study the structure and behavior of the complex molecules found in biological material such as amino acids in a protein, a large organic compound. Along those lines, it also explores the ways these molecules interact to form cells, tissues, and whole organisms. The biochemist seeks to determine how specific molecules such as protein, nucleic acids , lipids, vitamins, and hormones function in such processes. Particular emphasis is placed on regulation of the chemical reactions in the living cells.
Biochemistry has become the foundation for understanding all biological processes. It has presented explanations for the sources of many diseases in humans, animals, and plants alike through laboratory techniques such as chromatography, and spectroscopy. It can frequently propose ways by which such diseases may be treated or cured. Because biochemistry community is interested in unraveling the complex chemical reactions that occur in a wide variety of life forms, it offers the basis for practical advances in medicine, veterinary medicine, agriculture, and biotechnology. It also includes such exciting new fields as molecular genetics and bioengineering. The knowledge and methods developed by biochemists are applied to in all fields of medicine, for example, in agriculture and in many chemical and health related industries. The structural biochemistry helped to fight the AIDS epidemic because the structure of HIV protease, which should be blocked in order to prevent virus spreading, could be used as a reference to determine the types of molecules that might block the enzyme. Also, it helped patients with arthritis through the study of painkillers such as ibuprofen at the molecular level and by creating a new painkiller to shut down COX-2 so that ulcers would not form, and therefore prevent the side effects.
Biochemistry is also unique in providing education and research in protein structure or function and genetic engineering, the two basic components of the rapidly expanding field of biotechnology. As the broadest of the basic sciences, biochemistry includes many subspecialties such as neurochemistry, bioorganic chemistry, clinical biochemistry, physical biochemistry, molecular genetics, biochemical pharmacology, and immunochemistry.
Distinguishing Features of Living Organisms 
- Complex Internal Structures, there is a high degree of chemical complexity and microscopic organization. Thousands of molecules allow cells to maintain a very intricate internal structure, which include long polymers, each with characteristic sequences of subunits, its unique 3D structure and specific selection of binding sites.
- Systems are able to maintain equilibrium by extracting, transforming and using energy from the environment. This enables organisms to do mechanical, chemical and osmotic work.
- Reproduction, with defined function of organism's components, organisms are interacting with one another The interplay between organism have allowed changed in components that cause coordination and compensation to necessary adaptation to environment.
- Mechanisms for sensing and responding to alterations in organism environments A constant adjusting of internal chemistry in order to adapt to change in their local environment for better survival.
- Ability for precise self-replication and self-assemblyConstruction of entirely complete genetic material in each and every individual cell unique to the organism.
- A capability to evolve over time This fundamental unity of the living organism is reflected at the molecular level in similarities of gene sequences and protein structures.