Saturated and Unsaturated . These terms refer to the number of available bonds for more hydrogens in a hydrocarbon or other organic compound. If the compound is saturated then all the available bonds are taken up by hydrogens and other atoms and there are only single bonds between the carbons. In unsaturated compounds, there are double bonds between at least two of the carbons which could be broken to add more hydrogens. Fats are typically saturated while oils are unsaturated.
Science is the systematic study of the natural world.
Secondary structure . For proteins refers to that aspect of a proteins three dimensional structure which is due to the geometry of amino acid bonding between adjacent amino acids and short range hydrogen bonding. Typical secondary structures are pleated plates and alpha helices. Second Law of Thermodynamics . Another way of stating this is that any process that does work produces heat.