The Basic Chemistry of Life - Biochemistry, Bonds, Molecules, Reactions SGN 2 To really have an understanding of biology requires an appreciation of, and some knowledge of, biochemistry

We should all have a basic understanding of the fundamental characteristics of atoms   We should all have a basic understanding of the fundamental characteristics of molecules and ions

But in biology, compounds (2 or more atoms bonded together) can get very complex, so we must more closely consider biological compounds DNA Complex carbohydrates

In biological systems (“under physiological conditions”) molecules can be huge, ionized and can often exist as multimolecular complexes Multimolecular complexes can be stable and stay together for long periods DNA Hemoglobin (a protein) Multimolecular complexes can be transient Large multienzyme factors, called transcription factors, regulate protein synthesis

The forces that synthesize and shape these compounds, hold them together and modify them, and break them down, are fundamentally important in biological systems In most cases understanding the form of these biomolecules is essential to understanding their function Chemical bonds are largely responsible for giving compounds their shape and form

Strong bonds Covalent bonds always intramolecular

Weak bonds intra and intermolecular Hydrophilic bonds – between moieties of full or partial charge Hydrogen bond – attraction between 2 partially charged moieties Ionic bond (salt bridge) – attraction between 2 fully charged moieties Mixed bond - attraction of partial charge to full charge

Weak bonds intra and intermolecular Hydrophobic – forced attraction between two moieties with no charge or no partial charge

Molecules can … …be primarily hydrophobic or primarily hydrophilic …have hydrophobic and hydrophilic regions …can have one region that is entirely hydrophobic and one region that is entirely hydrophilic – this is called an amphipathic molecule

Chemical reactions make and break chemical bonds, reshaping reactants into products Students should know how to read a chemical equation Factors affecting the rate of a chemical reaction are extremely important in biological systems, as is regulating the rate of reactions and maintaining homeostasis Rate can be affected by catalysts, temperature, pH, concentration of reactants and products, etc.