Chapter 2. Matter – anything that occupies space and has mass Molecules – particles of matter...
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Transcript of Chapter 2. Matter – anything that occupies space and has mass Molecules – particles of matter...
Levels of Chemical Organization
Matter – anything that occupies space and has mass
Molecules – particles of matter made up of atoms
Atoms – protons, neutrons, electrons
•Atomic number is equal to the number of protons•Atomic mass is equal to the number of protons plus neutrons
CHEMICAL BONDING
Ionic bond – strong electrical attraction between ions that bare opposite electrical charges (Fig. 2-2); ionic molecules dissolve easily in water (dissociate)
Covalent bond – bond formed between two atoms that share a pair of electrons (Fig. 2-3)
Polar vs. Nonpolar Covalent Bonds
Polar Covalent Bond – electrons are not shared equally (ex. H2O)
Non Polar Covalent Bond – electrons are shared equally (ex. C-H)
Inorganic Chemistry
Molecules that generally do not contain carbon; there are no C-H or C-C bonds; smaller than organic molecules
H2O is an inorganic molecule – “universal solvent”
Organisms are composed mainly of water
Dehydration Synthesis – chemical reaction in which 2 molecules become covalently bonded by removing –H from one and –OH from another, removed atoms form water(Fig. 2-4)
Hydrolysis – the breaking apart of a molecule into its monomer subunits by the addition of the components of a H2O molecule into each of the covalent bonds linking the monomers
Acids, Bases & Salts – Fig. 2-5
Acid – a substance that releases H+ (hydrogen ions); pH<7
Base (alkaline) – a substance that releases OH- (hydroxide ions) or decreases H+ ; pH>7
Salt – substance composed of positively charged ions (not H+ ) and negatively charged ions (not OH-); usually neutral
Buffers – substances that react with strong acid or base to keep pH constant by absorbing or releasing H+ or OH- as needed; helps to maintain homeostasis
Organic Chemistry – Table 2-3Molecules contain H-C & C-C bonds
Carbohydrates – carbon + water – Fig. 2-6 glycogen – animals store energy in this carb. Starch – plants store energy in this carb.
Lipids – fats, oils and waxes – non polar, therefore they do not dissolve appreciably in water – Fig. 2-7, 2-8
Phospholipids – major component of cell membranes
Triglycerides – energy storage Cholesterol – steroid lipid – component of
cell membrane; precursor to steroid hormones
Proteins - most varied of all the organic molecules in function; enzymes, structural, hormones, immunological, membrane components – building blocks are amino acids
Enzyme – protein that acts as a catalyst – Fig. 2-10
Co-enzyme – some enzymes don’t function unless a co-enzyme is present (vitamins may serve this function)