CHEMISTRY matter anything that takes up space and has mass composed of atoms molecules elements are fundamental units of matter energy capacity to do work used in cells to perform specific functions 4 main elements o carbon o oxygen o hydrogen o nitrogen atomic mass protons neutrons atomic number protons atoms of the same element share the same properties isotope elements can have atoms with diff masses Diff of neutrons CHEMICAL BONDS bond interaction bw 2 atoms many diff types of bonds Covalent bonds o Octet rule most atoms want 8 e s in outer shell o Single bond sharing 1 pair of e s 1 e from each atom o Double bond sharing 2 pairs of e s o Some are nonpolar electrically neutral some polar have a and charge o Polar covalent bond results in regions of slight pos charge and regions of slight neg charge o Polar molecules can interact with ionic bonds Ionic Bonds o Atoms may gain lose e s o charged ions are cations lose an e o charged atoms are anions gain an e o ions of opposite charges are electrically attracted to each other o electrical forces hold ions together o form when e s are transferred from 1 atom to another o ions donate or accept e s so they can have 8 s in outer shell Hydrogen Bonds o charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules o this attraction forms weak bonds called H bonds o weak electrical bond bw molecules o forms bw chemical groups that carry partial electrical charges o usually forms bw H atom of one and an O2 atom of another molecule Patterns of Chemical Rxns o Synthesis anabolic atoms or molecules combine E is absorbed for o Decomposition catabolic molecule is broken down chem E is bond formation released Some elements are inert bc they have a full outer e shell WATER IS REQUIRED FOR LIFE Properties of water o Polar molecule oxygen loves e s electronegative o H bonds make liquid water cohesive o Due to H bonding water molecules can move from a plant s roots to o Insects can walk on water due to surface tension created by cohesive o Ability to store heat high specific heat moderates body temp and its leaves water molecules climate o Takes a lot of E to disrupt H bonds so water is able to absorb a great deal of heat E w o a large increase in temp o A water molecule takes E heat with it when it evaporates leading to evaporative cooling o H bonds hold molecules in ice farther apart than in liquid water ice is less dense than liquid water which causes it to float o Floating ice protects lakes and oceans from freezing solid o Polar or charged solutes dissolve when water molecules surround them forming aqueous solutions o Amt of dissolve solutes in per liter of solution is osmolarity of osmoles of solute liter of solution o Osmolality of osmoles of solute per kg solvent o Water dissolves polar molecules hydrophilic but not nonpolar molecules hydrophobic Inorganic compounds Water o Most abundant inorganic compound o Vital properties High heat capacity Polarity solvent properties Chemical reactivity Cushioning Salts Acids o Easily dissociate into ions in presence of water o Vital to many body fxs o Include electrolytes which conduct electrical currents o Release hydrogen ions o Are proton donors Bases o Release hydroxyl ions o Are proton acceptors Neutralization reaction o Acids and bases react to form water and a salt pH Measures relative concentration of hydrogen ions pH is equal to log10 of the hydrogen ion concentration in moles per liter o buffers are chemicals that can regulate pH change by accepting or donating extra H ions when needed o blood plasma 7 4 physiological neutral measure of H concentration chemistry of life is sensitive to acidic and basic conditions extra free H or OH can interact with matter especially proteins and change their shape form fx Change form change function Biomolecules carbs energy o contain C H O o include sugars and starches o classified according to size monosaccharides simple sugars disaccharides 2 simple sugars joined by dehydration synthesis polysaccharides long branching chains of linked simple sugars o glucose monomers starch and glycogen are polysaccharides which are stores of sugar for later use cellulose is a polysaccharide found in plant cell walls lipids make cell membranes cushioning o diverse compounds o consist of carbon and hydrogen atoms linked by nonpolar covalent bonds o monomers are glycerol and fatty acids o lipids fx as E storage o triglyceride consists of glycerol linked to 3 fatty acids o not soluble in water proteins make us look different from each other o made of monomers of amino acids o contain C O H N and sometimes S o account for over body s organic matter provide for construction materials for body tissues play vital role in cell fx o act as enzymes hormones antibodies o much of our E is expended building and maintaining proteins nucleic acids energy ATp and is also a messenger o info rich polymers of nucleotides o nucleic acids such as DNA and RNA serve as the blueprints for proteins and thus control the life of a cell o nucleotide bases adenine guanine cytosine thymine uracil make DNA and RNA can also be used as E sources ATP ATP creates E used by all cells E is released by breaking high E phosphate bond ATP replenished by oxidation of food fuels
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