Pairing of nitrogenous bases: The pairing of nitrogenous bases make up the "rungs" of the DNA "ladder". The structure of DNA base pairing dictates that thymine always pairs with adenine.
Unsaturated and Polyunsaturated Fatty acids: Within a fatty acid, when at least double bond is in the carbon chain, it is said to be unsaturated; more than one double bond, the chain is polyunsaturated.
Aerobic respiration: The cellular process by which an aerobic organism produces ATP, with the final electron acceptor being Oxygen is called Aerobic respiration. Respiration is the process by which ATP is produced from the oxidation of molecules. This process may be aerobic or anaerobic.
Autotroph or heterotroph: With regard to their requirements for carbon, bacteria are generally characterized as Autotroph or heterotroph. “Troph” refers to eating. The ability to use CO2 as a carbon source, much like plants, makes an organism “autotrophic” while that use carbon sources other than CO2 are called heterotrophs.
Enzyme: A protein that speeds up a chemical reaction by lowering the activation energy is called an enzyme. Enzymes speed up chemical reactions, such that these reactions occur at the rate at which the end products are needed.