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Fundamental Building Blocks



The fundamental building blocks of life form all the structures that make up microorganisms and drive all processes that make microbial life possible. At the smallest level, specific configurations of subatomic components form atoms of elements. Atoms of elements combine through chemical bonds and intermolecular forces such as hydrogen bonds and van der Waals forces to form molecules and compounds. Chemical reactions provide energy for microbial life as electrons involved in bonding move from an excited state to a lower energy state. Water and solutions containing water or other solvents play an important role in cell processes. Microbial survival depends on the balances between external and internal pH values and ranges. Critical biomolecules, such as carbohydrates, proteins, nucleic acids, and lipids, are important to sustaining microbial life, from generating and storing energy to maintaining genetic information.

At A Glance

  • Atoms are tiny particles that cannot be subdivided into smaller substances without losing their chemical properties.
  • Elements are made up entirely of one unique type of atom and are defined by the subatomic particles that come together in different combinations to form those atoms.
  • Different types of chemical bonds form when two or more atoms lose, gain, or share electrons. A covalent bond forms between atoms that share electrons, and an ionic bond forms when electrons are transferred from one atom to another.
  • Intermolecular forces include a hydrogen bond between a hydrogen atom and a negatively charged atom in a nearby molecule and a van der Waals attraction between temporarily charged atoms in neighboring molecules.
  • The energy that cells need in order to function is released in chemical reactions in cells.
  • Solutions are homogeneous mixtures of molecules in which one or more substances (solutes) dispersed in a dissolving medium (solvent).
  • The pH scale is used to measure the acid and base concentrations of solutions.
  • Biomolecules are organic compounds produced by living things. The four biomolecule families are carbohydrates, lipids, proteins, and nucleic acids, which form the basic structural units for DNA and RNA.
  • Carbohydrates are compounds consisting of only carbon, hydrogen, and oxygen that have structural and energy storage or transport roles
  • Lipids are nonpolar and hydrophobic chains of carbon with bound hydrogen atoms that are used to construct membranes and store chemical energy. Phospholipids, composed of two fatty acid chains and a phosphate group attached to a glycerol molecule, are used in the construction of the plasma membrane.
  • Proteins are complex folded chains of amino acids that provide structure and perform most of the functions in cells.
  • Nucleic acids provide the instructional material that guides the development, growth, and reproduction of cells.