Barron's AP Biology

matter

anything that has mass and takes up space

proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

electron

A subatomic particle that has a negative charge

ground state

state of atom in which all the electrons are in the lowest available energy levels

excited state

state of atom in which one or more electrons moves to a higher energy level when atom absorbs energy

isotope

atoms of one element that vary only in the number of neutrons in the nucleus (but are still chemically identical because same number of electrons in same configuration)

half-life

known rate of radioactive decay of some radioisotopes

radioisotopes

radioactive isotopes

radioactive iodine (iodine-131)

radioisotope used to diagnose and treat thyroid gland diseases

tracer

radioisotopes incorporated into a molecule and used to trace its path in a metabolic pathway

ionic bond

bond resulting from transfer of electrons

covalent bond

bond result from sharing of electrons

anion

negative ion (e.g. Cl-)

cation

positive ion (e.g. Na+, K+, Ca++)

molecule

structure of atoms formed by covalent bonds

nonpolar bond

covalent bond when electrons shared equally between two identical atoms (e.g. H-H)

diatomic molecule

molecule formed by two atoms of the same element with a non-polar bond (e.g. O-O)

polar bond

covalent bond when electrons shared unequally between two different atoms (e.g. C-H)

nonpolar molecule

electrons balanced and symmetrical in a molecule (e.g. carbon dioxide)

polar molecule

electrons unbalanced in a molecule (e.g. water)

hydrophilic

"water-loving", soluble in water (e.g. polar molecules, ions, charged substances)

hydrophobic

"water-hating", insoluble in water instead lipids (e.g. nonpolar molecules)

universal solvent

water dissolves so many substances

hydrogen bond

bond formed by weak attraction between a hydrogen atom and another atom resulting from ionic or polar charges

specific heat

the amount of heat a substance must absorb to increase the temperature of 1 gram of a substance by 1 degree C; high for water

heat of vaporization

the energy a substance must absorb in order to change from a liquid to a gas; high for water

cohesion tension

molecules of a substance attract one another; strong for water

transpirational-pull cohesion tension

water moves up from roots to leaves without expenditure of energy using transpiration

capillary action

force resulting from cohesion and adhesion

surface tension

type of cohesion enabling water to not break when touch surface lightly

spring overturn

cycling of nutrients in the lake when ice melts, becoming denser and sinking to circulate water and nutrients around the lake

pH

negative log of the hydrogen ion concentration; measure of acidity and alkalinity of a solution

buffer

substance that resists change in pH

bicarbonate ion

most important buffer in human blood

isomer

organic compounds that have same molecular formula but different structures

structural isomer

isomer that differs in arrangement of atoms

cis-trans isomer

isomer that differs only in spatial arrangement around flexible double bonds

enantiomer

isomer that is a mirror image (L for left-handed and D for right-handed)

carbohydrate

organic compound formed by carbon, hydrogen, and oxygen where hydrogen is always twice the oxygen; used for fuel and building materials

monosaccharide

monomer of carbohydrates; C6H12O6

glucose

monosaccharide that is the main sugar source

fructose

monosaccharide found in honey and fruits

galactose

monosaccharide found in milk

disaccharide

carbohydrate formed by joining two monosaccharides; C12H22O11

dehydration synthesis

two monomers joined together with the release of one molecule of water

condensation

another name for dehydration synthesis

maltose

disaccharide formed by two glucose

lactose

disaccharide formed by one glucose and one galactose

sucrose

disaccharide formed by one glucose and one fructose

hydrolysis

breakdown of organic compound by adding water

polysaccharide

polymers of carbohydrates formed by many monosaccharides joined together by condensation reactions

cellulose

structural polysaccharide that makes up plant cell walls

chitin

structural polysaccharide that makes up fungal cell walls and the exoskeleton of arthropods

starch

storage polysaccharide for plants; two forms are amylose and amylopectin

glycogen

storage polysaccharide for animals; found in liver and skeletal muscle

lipid

hydrophobic organic compound

fat

lipid for energy storage formed by glycerol and three fatty acids that is solid at room temperature

oil

lipid for energy storage formed by glycerol and three fatty acids that is liquid at room temperature

wax

lipid that is an ester of a fatty acid and alcohol

steroid

lipid consisting of four fused rings

glycerol

three-carbon alcohol with each carbon containing a hydroxyl group

fatty acid

hydrocarbon chain with a carboxyl group at one end

saturated fatty acid

fatty acid with only single bonds; solid at room temperature, come from animals, unhealthier

unsaturated fatty acid

fatty acid with at least one double bond; liquid at room temperature, come from plants, healthier

phospholipid

modified lipids consisting of only two fatty acids and one phosphate group attached to glycerol backbone; make up cell membrane

protein

complex, unbranched macromolecules that carry out many functions made of amino acids of sulfur, phosphorus, carbon, oxygen, hydrogen, and nitrogen

polymer

molecule consisting of many units called monomers

polypeptide

polymer of amino acids; not same as protein

amino acid

monomer of proteins

peptide bond

bond that joins amino acids in polypeptides

carboxyl group

carbon double-bonded to oxygen and bonded to hydroxyl

amine group

nitrogen bonded to two hydrogens

variable (R) group

attached to carbon backbone that is variable for amino acids

dipeptide

molecule consisting of two amino acids connected by one peptide bond formed by dehydration synthesis

conformation

unique shape of a protein that determines its function

primary structure

unique linear sequence of amino acids

secondary structure

hydrogen bonding within polypeptide molecule

tertiary structure

intricate three-dimensional shape or conformation of protein that is superimposed on its secondary structure

quaternary structure

proteins that consist of multiple polypeptide chains

alpha helix

the spiral shape of a protein's secondary structure (e.g. keratin)

beta-pleated sheet

the bended or folded form of a secondary structure (e.g. silk and spider webs)

fibrous protein

proteins that exhibit either alpha helix or beta-pleated sheet

keratin

fibrous protein of mainly alpha helix that makes up human hair

specificity

precise form of tertiary structure that determines function

denaturation

adverse conditions that alter the weak intermolecular forces that causes the protein to lose its characteristic shape and function

chaperonin

protein that assists in folding other proteins

prion

misfolded protein that when accumulated in brain, cause disease

X-ray crystallography

used to determine the 3D structure of many other proteins

bioinformatics

uses computation and math modeling to predict three-dimensional structure of resulting protein molecule

nucleic acid

polymer of nucleotides that encodes hereditary information

ribonucleic acid

single-stranded nucleic acid containing ribose and uracil

deoxyribonucleic acid

double-stranded nucleic acid containing deoxyribose and thymine

nucleotide

monomer consisting of phosphate, five-carbon sugar, and nitrogenous bases

nitrogenous base

identifies a nucleotide; e.g. adenine, cytosine, guanine, thymine, uracil

functional group

components of organic molecule involved in chemical reaction

theory of endosymbiosis

theory that mitochondria and chloroplasts were once free-living prokaryotes that merged with larger prokaryotes to form eukaryotes

eukaryotic cell

cell with nucleus and membrane-bound organelles

prokaryotic cell

cell without nucleus or membrane-bound organelles

cytosol

semifluid substance in which subcellular components are suspended