BIO 101 1st Edition Lecture 3 Outline of Last Lecture I Diets II Matter and Energy III Biological Molecules a Where are they Outline of Current Lecture IV Proteins a Can you eat too much b Functions V Enzymes and their functions a Enzymes in your life VI Alcohol Metabolism and Enzymes Current Lecture Pumpkin seeds Do they have biological Molecules o Enormous biological molecules in them Are they alive o It has the potential to grow Are vitamins and minerals biological molecules Vitamins are organic molecules Minerals are inorganic molecules These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Proteins are versatile macromolecules that serve as building blocks Protein diversity o Structural Hair fingernails feathers horns cartilage tendons o Protective Help fight invading microorganisms coagulate blood o Regulatory Control cell activity constitute some hormones o Contractile Allow muscles to contract heart to pump sperm to swim o Transport Carry molecules such as oxygen around your body Proteins are an essential dietary component Growth Repair Replacement Most individuals need 40 80 grams of protein per day As we eat protein and break it down into its parts through digestion our bodies are collecting the amino acids needed for various building projects Protein needs are higher for those who want to achieve the extensive muscle growth Pregnant woman also need more protein Can you eat too much protein YES Excess protein is converted into fat Excess protein makes your kidneys work harder Red meat pork poultry and seafood average 6 9 grams of protein per ounce o A serving of meat is about the size of the palm of your hand o 3 ounce chicken breast has about 20 grams of protein Seeds and nuts contain on average 4 8 grams of protein per quarter cup Cooked beans average about 7 8 grams per half cup Eggs contain about 6 8 grams of protein per egg Most vegetables contain about 1 2 grams of protein per ounce Take home Message 8 of the 20 amino acids are essential amino acids and cannot be made by the body so must be consumed in the diet Complete proteins contain all 8 essential amino acids while incomplete proteins do not Protein functions are influenced by their three dimensional shape Proteins are very specialized due to their complex shapes o Primary structure o Secondary structure o Tertiary Structure o Quaternary Structure Proteins are formed by linking individual amino acids together with a peptide bond in which the amino group of one amino acid is bonded to the carboxyl group of another Egg whites contain much protein Why does beating them change their texture making them stiff o Extreme environment heat pH disrupts protein shape and function Take home Message The particular amino acid sequence of a protein determines how it fold into a particular shape This shape determines many of the protein s features such as which molecules it will interact with When a protein s shape is deformed the protein usually loses its ability to function Enzymes make chemical reactions happen faster It is the speed of the chemical reactions that allow them to be alive Some reactions cant happen without them o Enzymes facilitate chemical reactions Enzymes can help to bring about chemical reactions in a variety of ways The enzyme lactase breaks down the milk sugar lactose into two simple sugars that can be used for energy Each enzyme has an active site that is perfect fit for its substrate An enzyme can help to bring about the reaction in a variety of ways These include o 1 By stressing bending or stretching critical chemical bonds increasing their likelihood of breaking o 2 By directly participating in the reaction perhaps temporarily sharing one or more electrons with the substrate molecule thereby giving it chemical features that increase its ability to make or break other bonds o 3 By creating a microhabitat that is conducive to the reaction For instance the active site might be a water free nonpolar environment or it might have a slightly higher or lower pH than the surrounding fluid Both of these slight alterations might increase the likelihood that a particular reaction occurs o 4 By simply orienting or holding substrate molecules in place so that they can be modified Enzymes are very choosy They bind only with their appropriate substrate molecules much like a lock that can be opened with one key Why do some adults get sick when they drink milk Are they allergic to milk Lactose intolerance o Even a slight alteration to an enzyme s active site can disrupt its functioning If the enzyme lactase is not built just right an individual cannot digest milk properly a condition called lactose intolerance Take Home Message Enzymes are proteins that help make and speed up chemical reactions They aren t permanently altered in the process but rather can be used again and again Enzymes in your life Meat Tenderizer o Contains enzymes called proteases breakdown proteins Contact lens solution o Contains proteases breakdown proteins o In your tears there are proteins those proteins can build on your contact lenses If you just use saline it doesn t work as well Spot removers for laundry o Contains proteases Breakdown proteins o Contains lipases breakdown lipids Enzymes only work in a narrow range of environmental conditions Hot water can help the enzymes in your laundry detergent work but temperatures that are too high can destroy enzymes o Cooking an egg destroys denatures the protein o High fever can kill a person The level of acidity is critical to enzyme functioning o Some digestive enzymes work in the acid environment of the stomach o Other digestive enzymes ex Pancreatic amylase need a more basic environment so it is secreted into the small intestine Salt concentration is also critical to enzyme functioning o Severe dehydration can alter salt concentrations and denature enzymes o Salting meat to make jerky denatures enzymes Alcohol Metabolism and Enzymes Acetaldehyde is a poison that is used to make plastics and tanning of leather Similar to formaldehyde Effects on the body o 1 Dehydration o 2 Damage to the liver o 3 Premature aging Problems with alcohol metabolism Alcohol intolerance is genetic caused by the inability to make the enzyme aldehyde dehydrogenase Many people of Chinese Korean and Japanese descent lack this enzyme 40 60 of vulnerability to addiction is genetic Alcohol addiction is not the same as