MCAT Biology Practice Questions And Answers

the chemical reaction that breaks down all the major macro-molecules - Answer- Hydrolysis What is the strongest type of INTER-molecular bonds? - Answer- Hydrogen bonds are the strongest intermolecular bonds.... diople-dipole bonds are weaker. . . Vander wall bonds are the weakest. Why is water a liquid at high temperatures? - Answer- Hydrogen bonding bonds the water molocules closer together. What is an ampipathic molecule? give an Example. - Answer- A molecule with both hydrophobic and hydrophilic regions. Example: PhoshpoLipid (Phospho=philic,lipid= phobic) What is a lipid? - Answer- A lipid is a biological molecule with low solubility in water. Lipid means fat. Liposuction is fat removal. Peptides are NOT lipids. What are the 6 major groups of lipids? - Answer- 1) fatty acids... the next 3 have a 3 carbon back bone: 2) Tri-glyceride 3) Phospholipids 4) Glycolipids 5) Steroids 6) Terpenes - A large class of organic compounds. examples: smelly pine oils, beer hops aroma and vitamin A. What is the structure of a Tri-glyceride? - Answer- triglicerides are esters. Composed from 3 carbon glycerol backbone and 3 fatty acid chains dangling. Each carbon chain is attached by an ester bond. What happens if you add water to an ester group in a Tri-glyceride? How is this reaction rate increased? - Answer- Water cleaves the ester bond into an alcohol and a carboxylic/ fatty acid. LIPASES speed are the enzyme that speed this reaction. in terms of water solubility, What is important to know about the longer the carbon chain in a Tri-glyceride when broken down? - Answer- longer carbon chains are less water soluble. In longer chains the polar carboxylic acid are less significant. How soluble is a Shorter chain fatty acids? - Answer- Shorter chain fatty acids are slightly water soluble. explain what