1. What are the four main types of organic compounds found in living organisms? Give an example and a function of each type. - The four main types of organic compounds are carbohydrates, lipids, proteins and nucleic acids. Carbohydrates are molecules composed of carbon, hydrogen and oxygen that provide energy and structural support for cells. Examples of carbohydrates are glucose, starch and cellulose. Lipids are molecules composed of carbon, hydrogen and oxygen that are insoluble in water and serve as energy storage, membrane components and signaling molecules. Examples of lipids are fats, oils and steroids. Proteins are molecules composed of amino acids that perform various functions such as catalysis, transport, movement, defense and regulation. Examples of proteins are enzymes, hemoglobin, actin and antibodies. Nucleic acids are molecules composed of nucleotides that store and transmit genetic information. Examples of nucleic acids are DNA and RNA. 2. What is the difference between a saturated and an unsaturated fatty acid? How does this affect their physical properties and health effects? - A saturated fatty acid is a fatty acid that has no double bonds between the carbon atoms in its hydrocarbon chain, while an unsaturated fatty acid has one or more double bonds. The presence of double bonds creates kinks in the hydrocarbon chain, which prevent the fatty acids from packing tightly together. This affects their physical properties such as melting point and solubility. Saturated fatty acids tend to have higher melting points and are more solid at room temperature than unsaturated fatty acids, which tend to have lower melting points and are more liquid at room temperature. The health effects of saturated and unsaturated fatty acids also differ. Saturated fatty acids are associated with increased risk of cardiovascular diseases, while unsaturated fatty acids are beneficial for lowering cholesterol levels and preventing inflammation. 3. What is the difference between a primary, secondary, tertiary and quaternary structure of a protein? How do these structures affect the function of a protein?