polar covalent bonds

the electrons spend more time closer to oxygen than hydrogen

polar molecule

overall charge is unevenly distributed

cohesion

substance held together by hydrogen bonds

adhesion

clinging of one substance to another

surface tension

measure of how difficult it is to stretch or break the surface of a liquid

kinetic energy

energy of motion

heat

a form of energy

temperature

a measure of heat intensity that represents the average kinetic energy of the molecules, regardless of volume

calorie (cal)

the amount of heat it takes to raise the temperature of 1 g of water by 1^oC

joule (J)

one joule equals 0.239 cal; one cal equals 4.184 J

specific heat

the amount of heat that must be absorbed or lost for 1 g of water to change its temperature by 1⁰C

evaporative cooling

the hottest molecules, those with the greatest kinetic energy, are the most likely to leave as gas

solution

a liquid that is a completely homogenous mixture of two or more substances

solvent

the dissolving agent of a solution

solute

the substance that is dissolved

colloid

a stable suspension of fine particles in a liquid

molecular mass

the sum of the masses of all the atoms in a molecule

hydrocarbons

organic molecules consisting of only carbon and hydrogen

isomers

compounds that have the same number of atoms of the same elements but different structures and hence different properties

structural isomers

differ in the covalent arrangements of their atoms

cis-trans isomers

carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds

enantiomers

isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon, one that is attached to four different atoms/groups of atoms

hydroxyl

-OH

alcohols

polar; can form hydrogen bonds with water molecules, helping dissolve organic compounds

carbonyl

>CO

Ketones: carbonyl group is within carbon skeleton

Aldehydes: carbonyl group is at the end of carbon skeleton

found in sugars; may be structural isomers

carboxyl

-COOH

acts as an acid - can donate H+ because the covalent bond between oxygen and hydrogen is so polar

amino

-NH₂

Acts as a base

sulfhydryl

-SH

can form covalent bond and stabilize protein structure

phosphate

-OPO₃ ^2-

have potential to react with water=energy

contributes negative charge

methyl

-CH₃

addition to DNA affects expression of genes

affect shape and function in sex hormones

polymer

a long molecule consisting of many similar or identical building blocks linked by covalent bonds

monomers

repeating units that serve as the building blocks of a polymer

dehydration reaction

two molecules are covalently bonded to each other with the loss of a water molecule

hydrolysis

reverse dehydration reaction

carbohydrates

include sugars and polymers of sugars

monosaccharide

have molecular formulas that are some multiple of the unit CH₂O

disaccharide

two monosaccharides joined by a glycosidic linkage

glycosidic linkage

covalent bond formed between two monosaccharides by a dehydration reaction

polysaccharides

macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages

starch

a polymer of glucose monomers

glycogen

a polymer of glucose

cellulose

structural polysaccharide; used in cell walls in plants

chitin

structural polysaccharide; carbohydrate used by arthropods to build their exoskeletons

lipids

mix poorly with water

fat

constructed from glycerol and fatty acids

fatty acid

has a long carbon skeleton (16-18 carbon atoms); carbon at one end is part of a carboxyl group (hence the acid) - rest is hydrocarbon chain

triacylglycerol

three fatty acids linked to one glycerol molecule

saturated fatty acid

no double bonds between carbon atoms in chain so as many hydrogen atoms as possible bond to the carbon skeleton

most animal fats

solid at room temperature

unsaturated fatty acid

1+ double bonds with one fewer hydrogen atom on each double-bonded carbon

plants and fish fats

liquid at room temperature

cis double bond prevents molecules from packing close together

phospholipid

make up cell membranes

steroids

lipids characterized by a carbon skeleton consisting of four fused rings

cholesterol

common component of animal cell membranes; precursor from which other steroids are synthesized

polypeptides

polymers of amino acids

protein

biologically functional molecule that consists of one or more polypeptides, each folded and coiled into a specific three-dimensional shape

enzymatic protein

selective acceleration of chemical reactions

defensive protein

protection against disease

storage protein

storage of amino acids

transport protein

transport of substances

hormonal protein

coordination of an organism's activities

receptor protein

response of cell to chemical stimuli

contractile and motor protein

movement

structural protein

support

amino acid

organic molecule possessing both an amino group and a carboxyl group

nonpolar side chains; hydrophobic amino acids (of protein)

glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, trytophan, proline

polar side chains; hydrophilic (of proteins)

serine, threonine, cysteine, tyrosine, asparagine, glutamine

electrically charged side chains; hydrophilic (of proteins)

aspartic acid, glutamic acid (negative)

lysine, arginine, histidine (basic/positive)

peptide bond

when two amino acids are positioned so that the carboxyl group of one is adjacent to the amino group of the other, they become joined by a dehydration reaction, resulting in a covalent bond

primary structure of protein

a linked series of amino acids with a unique sequence

secondary structure of protein

result of hydrogen bonds between the repeating constituents of the polypeptide backbone

alpha helix

beta pleated sheet

tertiary structure of protein

the overall shape of a polypeptide resulting from interactions between the side chains of the various amino acids

hydrophobic reaction contributes to tertiary structure

disulfide bridges further reinforce the shape of a protein

quaternary structure

overall protein structure that results from the aggregation of polypeptide subunits

denaturation

misshapen protein - biologically inactive

chaperonins

protein molecules that assist in the proper folding of other proteins

nucleic acids

polymers made of monomers called nucleotides

nucleotides

composed of nitrogenous base, five-carbon sugar (pentose), one or more phosphate groups

pyrimidine

six-membered sing of carbon and nitrogen atoms

cytosine (C, found in DNA and RNA, pairs with G), thymine (T, found only in DNA, pairs with A), uracil (U, found only in RNA)

purine

six-member ring fused to five member ring

adenine (A, found in DNA and RNA, pairs with T), guanine (G, found in DNA and RNA, pairs with C)

deoxyribose

sugar found in DNA

ribose

sugar found in RNA