AP Biology Unit 1: Chemistry of Life

essential elements (CHOPN)

carbon, hydrogen, oxygen, phosphorus, nitrogen

electronegativity

the measure of an atom’s ability to attract electrons to itself

covalent bond

when two or more atoms share electrons (between two nonmetals)

nonpolar covalent bond

electrons are shared equally

polar covalent bond

electrons are not shared equally

ionic bond

transfer of electrons from one atom to another atom (metal and nonmetal)

polarity

property of water to form polar covalent bonds between oxygen and hydrogen

cohesion

property of water to be attracted to other water molecules

adhesion

property of water to be attracted to other molecules

capillary action

the upward movement of water due to the forces of cohesion, adhesion, and surface tension

surface tension

surface water molecules experience a greater inward pull because there are no molecules above them to balance the forces

high specific heat

property of water to resist changes in temperature

high heat of vaporization

property of water to require a large amount of energy to evaporate due to strong hydrogen bonds

density

property of water to expand and become less dense when solidified due to hydrogen bonds

universal solvent

water’s ability to dissolve most molecules due to its polarity

organic compounds

compounds that contain carbon and hydrogen

macromolecules

molecules made of smaller subunits

four classes of macromolecules (CPNL)

carbohydrates, proteins, nucleic acids, lipids

polymers

chain-like macromolecules of similar or identical repeating units that are covalently bonded together

monomers

the repeating units that make up polymers

dehydration synthesis

two monomers are covalently bonded with the loss of water

hydrolysis

breads the covalent bonds in a polymer by adding water

carbon valence electrons

4 valence electrons

carbohydrate essential elements

carbon, hydrogen, oxygen

carbohydrates

includes sugars and polymers of sugars

monosaccharide

simple sugars

disaccharide

two monosaccharides joined together by covalent bonds; energy transfer

polysaccharide

polymer with many sugars joined via dehydration synthesis

storage polysaccharide

starch (plants) and glycogen (animals)

cellulose

structural polysaccharide that forms plant cell walls

chitin

structural polysaccharide that forms exoskeleton of arthropods

lipid

class of molecules that do not include true polymers and are nonpolar

types of lipids

fats, phospholipids, steroids, cholesterol

major functions of lipids

provide energy storage, support cell function, provide insulation

lipid composition

glycerol and fatty acids

glycerol

an alcohol (hydroxyl group)

fatty acid

long carbon chains with a carboxyl group at one end

ester linkage

bond between a hydroxyl and carboxyl group; how fatty acids join to a glycerol

saturated fatty acid

single bonds between carbons in the carbon chain

unsaturated fatty acid

contains one or more double bonds that cause the fatty tails to form kinks and become more liquid

phopholipid composition

two fatty acids attached to a glycerol and a phosphate

steroid

hormones that support physiological functions and have four fused rings

cholesterol

provides structural stability to animal cells

monomer of proteins

amino acids

primary structure of a protein

linear sequence of amino acids (genetically determined)

secondary structure of a protein

coils and folds due to hydrogen bonding within the polypeptide backbone

tertiary structure of proteins

3D folding due to interactions between the side chains of the amino acids

quaternary structure of proteins

association of 2 or more polypeptides

amino acid composition

molecules that have an amino and carbonyl group

protein

molecule consisting of polypeptides folded into a 3D shape

protein essential elements

carbon, hydrogen, oxygen, nitrogen, sulfur

formation of peptide bonds

the carboxyl group of one amino acid must be positioned next to the amino group of another amino acid

polypeptide

many amino acids linked by peptide bonds

formation of a protein

amino acid - peptide - polypeptide - protein

nucleic acid

polymers made of nucleotide monomers

nucleic acid function

store, transmit, and express hereditary information

monomer of nucleic acids

nucleotides

nucleotide composition

nitrogenous base, five carbon sugar, phosphate group

types of nitrogenous bases

purines and pyrimidines

pyrimidine

1 ring with 6 atoms

purine

1 ring with 6 atoms bonded to 1 ring with 5 atoms

five-carbon sugar

a sugar is bonded to the base

phosphate group

added to the 5’ carbon of the sugar to form a nucleotide

polynucleotide

phosphate groups link adjacent nucleotides

polynucleotide directionality

5’ to 3’