BSCI 105 Atomic Structure and Bonds 9 2 11 Thermonuclear fusion E mc2 Hydrogen Atoms Energy Mass Lost Speed of light squared What causes building of larger elements Caused the creation of elements Doppler Shift the change in wavelengths as an object approaches and leaves Sun burns hydrogen and makes helium ATOMIC NUMBER of protons ATOMIC MASS of protons neutrons Electron orbital shells are spherical 1s first shell has least energy INERT an element with only paired electrons Lithium splits water leaving a hydroxyl group and hydrogen gas ION charged atom OCTET RULE 8 electrons in outermost shell Covalent Bond Sharing of electrons between atoms Equal sharing NON POLAR covalent bond CH4 Unequal sharing POLAR covalent bond H2O Polar dissolves in polar CATIONS Atoms that give up one or two electrons give them up to become ANIONS Atoms that gain one or two electrons assume a negative charge positively charged Monovalent cation gave up one electrons Divalent cation gave up two electrons Monovalent anions gains one electrons Divalent anions gains two electrons Structure leads the function structure of molecules Functional Groups HYDROXYL group OH always polar METHYL CH3 non polar AMINO NH2 polar CARBOXYL O C OH COOH polar A MOLE is a measure of concentration of solute in a solution One MOLE 6 02 x 1023 PRESSURE is the concentration of gas in a solution Atomic COMPOSITION gives a molecule a specific 3 dimensional shape polarity and chemical reactivity 9 7 11 Water And Life Water molecules have hydrogen bonds between an oxygen atom and another molecule s Hydrogen atom When water is in its liquid form Hydrogen bonds are very fragile about 1 20th as strong as a covalent bond and they break and reform very frequently each lasting a few trillionths of a second Properties of Water Four emergent properties of water Cohesive behavior Ability to Moderate Temperature Expansion upon Freezing and Versatility as a Solvent Surface Tension COHESION Water molecules sticking together by polar hydrogen bonds ADHESION Water molecules hang on to other surfaces High boiling point High specific heat Specific Heat The amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1oC Solvent for other polar molecules Evaporation takes heat away Sweating or Panting Forces non polar molecules to adhere together in an organized structure Only substance that freezes from top down density decreases when frozen It ionizes or dissociates At equilibrium there is a ratio of products to reactants Not all reactants become products COLLOID a stable suspension of fine particles in a liquid MOLARITY the number of moles of solute per liter of a solution When water dissociates it leaves a Hydrogen ion H and a Hydroxide ion OH LAW OF MASS ACTION restores equilibrium in a reaction Add reactants to one side of reaction drives to other side Human pH 7 4 ACID donates a proton H The more Hydrogen H ions the more Acidic BASE removes or accepts a proton H The more Hydroxide OH ions the more Basic Life is based on macromolecules changing shape When you hyperventilate your pH goes UP Lose protons pH becomes very basic pH of 1 molar is 0 pH of 10 molar is 1 9 9 11 Proteins All proteins have an amino group NH2 at one end and a Carboxyl group COOH at the other end at pH 7 4 and R group in between Amino Acids Essential amino acids must take into diet Nonessential amino acids If the pH of the protein is lowered the protein s charge becomes more positive By adding more protons H Blood can get more acidic with certain diseases Diabetes Enzymatic Proteins regulate metabolism by acting as CATALYSTS Chemical agents that selectively speed up chemical reactions without being consumed by the reaction All proteins are unbranched polymers constructed from the same set of 20 amino acids Polypeptides Polymers of amino acids Peptide bond Covalent bond between two amino acids A protein s function depends on its ability to recognize and bind to some other molecule Four levels of protein structure 1 Linear chain of amino acids 2 Regions stabilized by hydrogen bonds between atoms of the polypeptide backbone Coils and folds in polypeptide chains a Alpha Helix b Beta Pleated Sheet 3 Three dimensional shape stabilized by interactions between side chains a The protein s functional shape b Prosthetic group not an amino acid artificial group that helps function c Hemoglobin i HbF Hemoglobin fetal binds oxygen very tightly ii HbA Hemoglobin adult binds oxygen less tightly d Hydrophobic interactions occur during formation of tertiary structure where the hydrophobic side chains cluster in the center of the protein e Difulside Bridges covalent bonds that further reinforce the shape of a protein 4 Association of multiple polypeptides forming a functional protein Denaturation protein unravels and loses its native shape causing it to become inactive Due to alteration of pH Salt Concentration Temperature etc Often Occurs when transferred from an aqueous solution to a nonpolar solvent or overheat Chaperone Proteins aids the correct folding of proteins Protein Functions Enzymes Transport Sites For polar molecules through membranes Membrane Channels Extracellular matrix Intracellular structural elements Receptors for signal molecules ORGANIC MOLECULES have at least carbon hydrogen and oxygen With any source of energy it is very simple to make organic molecules starting with any variety of inorganic molecules ABIOGENIC synthesis of organic molecules without life 9 9 11 Living Growth Response to Environment Reproduction Contains Cells Respiration Metabolism Different Levels of Organization Homeostasis 9 12 11 Carbohydrates Polymers form by dehydration synthesis Take out HO and H Dehydration reaction Two molecules bonded together with the loss of a water molecule Hydrolysis In order to break down a polymer add water Add H2O between polymer and unlinked monomer Carbohydrates Triose sugars Pentose sugars Hexose sugars Include Glucose and Galactose Monosaccharide single sugar Disaccharide two sugar units Tri and Polysaccharides Disaccharides Polysaccharides link from Carbon 1 to Carbon 4 of another Sugar is POLAR sugar Called a 1 4 Linkage Alpha Linkage is when all Carbon 6 are on top Starch Beta Linkage is when Carbon 6 s alternate top and bottom Cellulose We have enzymes to break down alpha but not to break down beta When linked from Carbon 6 a branch is created off of the polysaccharide helices 1 6 linkage Why is alpha 1 4 1 6 good for
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