main trace elements
iron, iodine, copper, zinc
isotope
same number of protons, different number of neutrons
radiometric dating
a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed
compounds
2+ individual elements combined in a fixed ratio
covalent bond
two atoms SHARE one or more pairs of outer shell electrons
ionic bonds
formed when electrons are TRANSFERRED from one atom to the other
What electronegative atoms do hydrogen atoms typically form hydrogen bonds with?
nitrogen, oxygen, fluorine
hydrogen bond
a weak attraction between a covalently bonded (partially positive) hydrogen atom with another electronegative atom
ion
atoms or molecules with electrical charges (from a gain or loss of 1+ electrons)
polar covalent
electrons shared UNEQUALLY (polar molecule)
nonpolar covalent
electrons shared EQUALLY
polar
having electrical or magnetic polarity, two opposites
cohesion
strong tendency to stick together (e.g. transpiration, capillary action)
adhesion
stick to other substances, specifically polar ones (e.g. difficult to separate glass films with water between, capillary action)
surface tension
hydrogen bonds at the surface hold together via cohesion (e.g. leaves sit on top of water)
key properties of water
less dense solid than liquid (expands when freezes), cohesion, adhesion, solvent for polar / charged molecules, high specific heat capacity, high heat of vaporization
specific heat capacity
amount needed to increase temperature by one degree
heat of vaporization
heat needed for a substance to boil
acidic
gives H+ to a solution (protons!), below 7
basic (alkaline)
compound that accepts H+ and gives OH-, above 7
neutral
pure water, not acidic or basic, exactly 7
alkaline
having a pH greater than 7
What does an increase in H+ ions do to a solution?
decrease its pH
pH scale (potential hydrogen)
used to describe a solutions acidity, ranges from 0-14, each unit is 10x change to the H+ of a solution (base 10)
organic compound
made by living cells/organisms, must contain carbon
inorganic compounds
chemical compound that lacks carbon-hydrogen bonds
dehydration synthesis (condensation)
FORMS covalent bonds between monomers to form a polymer by removing a water molecule
hydrolysis
BREAKS bonds between monomers, uses water
carbohydrates
sugars, used for energy fuel, CHO
disaccharide
two monosaccharides linked via dehydration synthesis (e.g. maltose, sucrose, lactose)
glycosidic linkage
when two monosaccharides are joined, hydrogen (-H) links with hydroxyl (-OH) → water, hold hands via one oxygen molecule
glucose
monosaccharide used in photosynthesis for energy
fructose
common monosaccharide in fruits
How do you recognize glucose or fructose?
lots of OHs and Hs attached, C6H12O6 (isomers)
What is starch made of?
amylose and amylopectin with alpha bonds between glucose
starch
sugar storage molecule in plants
amylose
unbranched polysaccharide, linear
amylopectin
branched chains of glucose monomers
cellulose
in plant cell walls (fiber) and fungus / arthropod exoskeletons, made of beta glucose, linked with beta bonds (stronger), lots of cross links
glycogen
sugar storage molecule in animals mainly in liver and muscle cells, linked with alpha bonds
amino group
N connected to two H's, in amino acids (NH2)
carboxyl group
C double bonded to an O and single bonded to an OH, in amino acids (COOH)
R-group (side chains)
determine properties of different amino acids; elements, polarity, charge, shape differentiate
ionic
polar, charged
protein
any of a class of nitrogenous organic compounds that have large molecules composed of one or more long chains of amino acids, CHON(S)
How is secondary structure held together?
hydrogen bonds between the H in the amino group and the O of the carboxyl group
How is tertiary structure held together?
R groups attract each other (with hydrophobic and hydrophilic properties)
How is quaternary structure held together?
bonding interactions of subunits / polypeptide chains
chaperone proteins (chaperonins)
help protein fold properly, make process more efficient
lipids
nonpolar (or amphipathic, mainly nonpolar) and hydrophobic compounds, CHO
triglycerides
THREE fatty acids (chains). ONEEE GLYCEROLLLL. (glycerol backbone), fats and oils
phospholipids
TWO fatty acids and phosphorus (amphipathic), make up plasma membrane
steroids
4 carbon skeleton rings (3 hexagons, 1 pentagon), hormones and cholesterol in animal cell membranes
ester linkage
linkage bond between lipids
sugar-phosphate phosphodiester bonds
linkage bond between nucleic acids
nucleotides
monomers of nucleic acids; made of a nitrogenous base, phosphate group, and a 5-carbon sugar