Water is the most important compound in living organisms. Organisms are comprised of 70-90% H2O. Water resists temperature change and when frozen is less dense than liquid H2O. Water is polar, has adhesive and cohesive properties. Proteins provide structure for tissues and Nucleic acids are the most complex organs. They also carry out cell metabolism. biomolecule that stores cellular Proteins are comprised of amino acids. information. They are polymers Enzymes are types of proteins that act as formed from nucleotides. Two catalysts. Proteins twist and fold, keeping nucleic acids are DNA and RNA. their shape with the help of hydrogen bonds. • Carbohydrates are composed of carbon, hydrogen and oxygen. Simple sugars are monosaccharide's and complex sugars are polysaccharides. Starch, glycogen and cellulose are all forms of carbohydrates. It can give structural support, energy and is also found in the cell wall. • Glucose • Lipids are nonpolar and are usually referred to as fats. They can store energy in the cell and be found in the cell membrane. Lipids are either saturated and unsaturated. Cholesterol is also a lipid.