BIOL 101 1nd Edition Lecture 4 Outline of Last Lecture Macromolecules I II III Four major macromolecules Carbohydrates Lipids Outline of Current Lecture I Lipids continued II Protein Structure a Amino Acids b How are proteins made from amino acids c A protein shape determines its function Lets use this table to highlight the four different levels of protein structure and briefly characterize each Current Lecture 5 Trans fats are made when manufacturers add hydrogen to vegetable oil a process called hydrogenation This increases the shelf life and flavor stability of foods containing these fats Trans fat is known to increase blood levels of low density lipoprotein LDL or bad cholesterol while lowering levels of high density lipoprotein HDL known as good cholesterol B Phospholipids a major component of cell membranes 1 Monomers fatty acid glycerol phosphate group the hydrophilic part of the phospholipid 2 Hydrophobic tails hydrophilic heads tails don t like water while the heads like water C Other lipids Steroids cholesterol Detergents surround oil in water and form a protective layer so that the oil molecules cannot clump together The detergents disperse the oil into small droplets and in the water such as when you use soap to wash an oily dish What kind of properties would the detergent have to have to interact with both water and the lipid Draw a model of the oil dispersant and water mixed together 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 What did the dispersant detergent Corexit do to help during the BP oil spill Over 800 000 gallons of dispersants had been applied to Gulf waters mainly via helicopter but also includes 100 000 gallons that were injected deep underwater The detergent disperses the oil molecules and breaks up the oil slick so the molecules will be diluted IV Protein Structure A Amino acids monomers of protein 1 20 different amino acids 2 AA s consist of amino group NH2 and carboxyl group COOH 3 AA s have different R groups 4 How big is a protein 100 1000 can be very small You have been hired as an illustrator for a new introductory biology textbook The authors want you to draw a picture to demonstrate how two amino acids far apart in primary structure can interact in their tertiary structure What does your rough sketch look like Compare with and critique your partner s sketch Draw a second stretch demonstrating what a mutation in one amino acid might do to your tertiary structure Primary structure is a long chain Secondary structure forms a coil Tertiary structure the protein can fold When two amino acids have an interaction and form a 3d structure B How are proteins made from amino acids Through a dehydration reaction and the removal of a water molecule Amino acid OH H Amino Acid Amino acid Amino Acid aka dipeptide Removal of H2O Apply what you know about how proteins are made and predict how amino acids could be released from the polypetide chain Through hydrolysis adding a water molecule C A proteins shape determines its function Lets use this table to highlight the four different levels of protein structure and briefly characterize each Peptide bond forms between two amino acids Protein Structure Description Definition Types of Bonds found in this structure Primary Linear sequence of amino acids Covalent peptide bonds strong bond Hydrogen bonding between atoms of the polypeptide backbone Hydrogen weak bonds Secondary Its curled up like a coil alpha helix Tertiary Folds into a 3D globular shape formed specifically by interactions between the R groups Ioninc bonds Hydrogen bonds Covalent bonds occasionally Quaternary Multiple polypeptides two polypeptides coming together and interacting ALL of the above Observation Hair is made of proteins primarily a structural fibrous protein called keratin People with curly hair have more covalent bonds between R groups in their keratin compared to people with straight hair When curly hair is straightened with heat like a flat iron or blow dryer the straightening is not permanent Water humidity causes it to curl up again Curly hair can be permanently straightened using a chemical Propose an explanation for why heat is not permanent but chemical straightening is Use words related to protein structure The heat breaks the hydrogen bonds which are weak and can reform when exposed to water molecules in the air Chemicals can break the covalent bonds which are much stronger than the hydrogen bonds