Chemistry Basics for Biologists

Welcome to our exploration of atomic structure and the elements of life!At the heart of all living things are atoms, the fundamental building blocks of matter.The nucleus contains positively charged protons, while negatively charged electrons orbit in energy shells.Life is primarily built from four key elements: Carbon, Hydrogen, Oxygen, and Nitrogen, known as CHON.Each element has a unique electron configuration that determines its chemical behavior.The electrons in the outermost shell, called valence electrons, are crucial for chemical bonding.These electrons can be shared between atoms to form chemical bonds, which we'll explore in our next section on chemical bonding.Covalent bonds form when atoms share electrons. Let's look at how two hydrogen atoms form a hydrogen molecule.Electronegativity measures an atom's tendency to attract electrons. This property determines whether bonds will be polar or nonpolar.Proteins form through peptide bonds between amino acids. These covalent bonds create the protein's primary structure.DNA's double helix structure is stabilized by hydrogen bonds between base pairs, while covalent bonds form the sugar-phosphate backbone.Lipid bilayers form through hydrophobic interactions, with polar heads facing the aqueous environment and nonpolar tails facing inward.pH is a measure of hydrogen ion concentration in a solution, ranging from 0 to 14.The pH scale is logarithmic, meaning each unit represents a tenfold change in hydrogen ion concentration.Buffer systems help maintain stable pH by resisting changes in hydrogen ion concentration.The bicarbonate buffer system is particularly important in blood pH regulation.pH changes can significantly affect protein structure. At optimal pH, proteins maintain their proper shape.When pH becomes too acidic or basic, proteins can become denatured, losing their functional shape.The body maintains blood pH within a very narrow range through multiple systems working together.This includes the respiratory system, renal system, and chemical buffer systems.pH disturbances can have serious consequences for cellular function and survival.