BIO 105 1st Edition Lecture 4Chemistry & MacromoleculesLast Lecture Review:The characteristics of communities and populations were defined. Lecture Outline:I. Be able to identify the difference between an element, compound, and atomII. Understand the charges that make up an atomIII. Know the different types of bonds and their characteristicsIV. Understand the pH scale V. Be able to identify and characterized macromoleculesLecture: Living Organisms are composed of about 25 chemical elements- 4 of these make up 96% of livingmatter & 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- H₂O 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 numberThese 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 protonso Repel one anothero Are attracted to protons in the nucleuso 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 Bondso Nonpolar- atoms share electrons- pull equallyo Polar- electrons spend more time near nucleus with most protons- unequal 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 andother “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 fluidHighest H+ Lowest H+0--------------------7--------------------14Acidic 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 pHREMEMBER ORGANIC=CARBON Organic Compounds- The following are Macromolecules: Carbohydrates (sugars)- immediate energyo Include both simple and complex sugarso 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 pieceso Plants storage form of carbohydrates is starcho Humans storage form of carbohydrates is Glycogen Lipids (fats)-long term storageo Only Macromolecule that does not form polymerso Hydrophobic- little or no affinity for water (does not like water)o Nonpolar covalent bondso Lipids are made up of glycerol and fatty acido Saturated Fatty Acid- no carbon-carbon double bonds, a hydrogen at every possible position **Hydrogen is everywhere, it is “saturated” in hydrogeno Unsaturated Fatty Acid- one or more carbon-carbon double bonds, have a “kink” where double bond iso The function of a lipid is for energy storage Proteins-everything elseo Amino acids make up proteinso Three main levels of structure: primary, secondary, tertiary Nucleic acids- informational polymerso 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