BIO 105 1st Edition Lecture 4 Chemistry Macromolecules Last Lecture Review The characteristics of communities and populations were defined Lecture Outline I Be able to identify the difference between an element compound and atom II Understand the charges that make up an atom III Know the different types of bonds and their characteristics IV Understand the pH scale V Be able to identify and characterized macromolecules Lecture Living Organisms are composed of about 25 chemical elements 4 of these make up 96 of living matter are the main ingredients of macromolecules Oxygen Hydrogen Carbon Nitrogen Matter anything that takes up space and has mass Element substance that cannot be broken down to other substances by ordinary means smallest fundamental unit Compound substance containing two or more elements in a fixed ratio H O Atom smallest unit of an element Smallest to Biggest Atom Element Compound Atoms are made up of Protons Electron Neutrons Protons have positive charges each has a unique number 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 Electrons have negative charges equals the number of protons o Repel one another o Are attracted to protons in the nucleus o Move in orbitals volumes of space that surround the nucleus Neutrons have no charge 0 variations in numbers are called isotopes How atoms work The atom s center is made up of protons and neutrons Around the atom are rings or layers In the first layer there are ONLY two seats for electrons On the next layers there are ONLY eight seats for electrons The electrons must fill up the seats in layer one before filling up the seats in layer two and so on In layer two where there are eight seats the electrons sit the farthest from one another Basically like when a guy uses the urinals they do not stand directly next to another person instead they go farther down When the electrons fill up the seats farthest away they then fill in the rest of the seats This is the same concept with electrons P rotons are P ositive N eutrons are N eutral Isotopes are atomes of an element with different numbers of neutrons Electron Arrangement determines the chemical properties of an atom Bond union between electron structures of atoms Ionic bonds weak strong One atom loses electrons becomes positively charged ion Another atom gains these electrons becomes negatively charged ion Charge difference attracts the two ions to one another Covalent bonds strong Atoms share a pair or pairs of electrons to fill outermost shell Ex Big dog playing tug of war versus small dog playing tug of war Nonpolar Bonds vs Polar Bonds o Nonpolar atoms share electrons pull equally o Polar electrons spend more time near nucleus with most protonsunequal pull Hydrogen bonds weak Atom in one polar covalent molecule is attracted to oppositely charge atom in another such molecule or in same molecule these are important in proteins and other folded molecules like DNA Properties of Water Bonds to hydrophilic water loving substances like sugars Repels hydrophobic ones like oils Stabilizes temperature release heat stabilize cells Expands when it freezes hydrogen bonds resist breaking Cohesive resists breaking when stretched Capacity to dissolve substances ions and polar molecules easily dissolve in it pH Scale Measures H concentration of fluid Highest H Lowest H 0 7 14 Acidic Neutral Basic A comes before B so acidic comes before Basic Acids and Bases Acids Donate H when dissolved in water Acidic solutions have pH 7 Bases Accept Take H when dissolved in water Basic solutions have pH 7 Buffer System Minimizes shifts in pH REMEMBER ORGANIC CARBON Organic Compounds The following are Macromolecules Carbohydrates sugars immediate energy o Include both simple and complex sugars o Easier to breakdown simple sugars than complex sugars Ex It is easier for a kid to break apart to lego pieces rather than 2 000 lego pieces o Plants storage form of carbohydrates is starch o Humans storage form of carbohydrates is Glycogen Lipids fats long term storage o Only Macromolecule that does not form polymers o Hydrophobic little or no affinity for water does not like water o Nonpolar covalent bonds o Lipids are made up of glycerol and fatty acid o Saturated Fatty Acid no carbon carbon double bonds a hydrogen at every possible position Hydrogen is everywhere it is saturated in hydrogen o Unsaturated Fatty Acid one or more carbon carbon double bonds have a kink where double bond is o The function of a lipid is for energy storage Proteins everything else o Amino acids make up proteins o Three main levels of structure primary secondary tertiary Nucleic acids informational polymers o Store and transmit hereditary information Making Polymers Condensation Reactions also called Dehydration Synthesis Forms polymers from subunits Enzymes remove OH from one molecule ex an alcoholic beverage Less water larger molecules Breaking Apart Polymers cleavage or hydrolysis Add water smaller molecules