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 elementso carbono oxygeno hydrogeno 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 neutronsCHEMICAL BONDS- bond: interaction bw 2 atoms, many diff types of bonds- Covalent bondso Octet rule: most atoms want 8 e-s in outer shello Single bond: sharing 1 pair of e-s (1 e- from each atom)o Double bond: sharing 2 pairs of e-so Some are nonpolar (electrically neutral), some polar have a + and – chargeo Polar covalent bond: results in regions of slight pos charge and regions of slight neg chargeo Polar molecules can interact with ionic bonds - Ionic Bondso Atoms may gain/lose e-so + 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 othero electrical forces hold ions togethero form when e-s are transferred from 1 atom to anothero ions donate or accept e-s so they can have 8-s in outer shell- Hydrogen Bondso charged regions on water molecules are attracted to the oppositely charged regions on nearby moleculeso this attraction forms weak bonds called H bondso weak electrical bond bw molecules o forms bw chemical groups that carry partial electrical chargeso usually forms bw H atom of one and an O2 atom of another molecule- Patterns of Chemical Rxnso Synthesis: anabolic, atoms or molecules combine, E is absorbed for bond formationo Decomposition: catabolic, molecule is broken down, chem. E is released- Some elements are inert bc they have a full outer e- shellWATER IS REQUIRED FOR LIFE- Properties of watero Polar molecule: oxygen loves e-s (electronegative)o H bonds make liquid water cohesiveo Due to H bonding, water molecules can move from a plant’s roots to its leaveso Insects can walk on water due to surface tension created by cohesive water moleculeso Ability to store heat (high specific heat) moderates body temp and climateo 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 tempo A water molecule takes E (heat) with it when it evaporates leading to evaporative coolingo 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 solido Polar or charged solutes dissolve when water molecules surround them, forming aqueous solutionso 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 solvento Water dissolves polar molecules (hydrophilic) but not nonpolar molecules (hydrophobic)Inorganic compounds- Watero Most abundant inorganic compoundo Vital properties High heat capacity Polarity/solvent properties Chemical reactivity Cushioning- Saltso Easily dissociate into ions in presence of watero Vital to many body fxso Include electrolytes which conduct electrical currents- Acidso Release hydrogen ionso Are proton donors- Baseso Release hydroxyl ionso Are proton acceptors- Neutralization reactiono Acids and bases react to form water and a saltpH- Measures relative concentration of hydrogen ions- pH is equal to =log10 of the hydrogen ion concentration in moles per litero buffers are chemicals that can regulate pH change by accepting or donating extra H+ ions when neededo 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 functionBiomolecules- carbs-energyo contain C, H, Oo include sugars and starcheso classified according to size monosaccharides-simple sugars disaccharides-2 simple sugars joined by dehydration synthesis polysaccharides-long-branching chains of linked simple sugarso 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, cushioningo diverse compoundso consist of carbon and hydrogen atoms linked by nonpolar covalent bondso monomers are glycerol and fatty acidso lipids fx as E storageo triglyceride consists of glycerol linked to 3 fatty acidso not soluble in water- proteins-make us look different from each othero made of monomers of amino acidso contain C, O, H, N, and sometimes So account for over ½ body’s organic matter provide for construction materials for body tissues play vital role in cell fxo act as enzymes, hormones, antibodieso much of our E is expended building and maintaining proteins- nucleic acids-energy/ATp and is also a messengero info-rich polymers of nucleotideso nucleic acids such as DNA and RNA serve as the blueprints for proteins and thus control the life of a cello 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 breakinghigh E phosphate bond, ATP replenished by oxidation offood
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