Biology Unit 2 - Molecules

matter

anything that takes up space and has mass

mass

the quantity of matter in an object

weight

the force of gravity on mass

atom

smallest component of an element that still retains its properties

element

substance that can't be further broken down without changing its properties

atomic nucleus

the center of the atom, contains protons and neutrons

atomic mass

the mass of an atom, protons + weighted average of neutrons in all isotopes existing in nature

proton

positively charged subatomic particle found in the nucleus, number determines the element of the atom

electron

a negatively charged subatomic particle found rapidly circling the nucleus in orbitals

neutron

neutrally charged subatomic particle found in the nucleus, responsible for isotopes

orbitals

regions around the nucleus where electrons are found

valence orbital

the outermost orbital from the nucleus, empty spots in this orbital determine the atom's ability to bond

isotopes

variants of an element with differing numbers of neutrons

compound

molecule with two or more elements in fixed proportions

chemical formula

shows type and proportions of atoms in a compound

noble/inert

an atom from an element that has a full valence orbital and thus doesn't bond

bonds

ways for atoms to exchange electrons to fill their valence orbital/become stable

covalent bond

a chemical bond where atoms share one or more pairs of electrons

molecule

the smallest amount of a substance that retains its properties

ionic bond

a chemical bond where one atom transfers an electron to another atom, creating one positive ion and one negative ion that attract each other

energy

the ability to do work, cannot be created or destroyed

thermal energy

a form of energy that must be added or removed from a substance to change its state of matter

chemical reaction

one or more substances change (form and break bonds) to produce one or more different substances

metabolism

chemical reactions that occur to provide energy for the body

physical change

a change in a substance that does not change its chemical makeup

chemical change

a change in a substance that produces one or more new substances (a chemical reaction)

polar molecules

covalently bonded molecules where electrons are shared unequally

solubility

the ability of a substance to dissolve in another substance

hydrogen bond

attractive force between water molecules caused by water's polarity that leads to many special properties of water

special properties of water

cohesion, adhesion, heat capacity, evaporative cooling, density of ice, solubility

cohesion

attractive force that holds molecules of a single substance together, the ability of a substance to stick to itself

adhesion

attractive force between particles of different substances

capillarity

attraction between molecules resulting in rise of the surface of a substance when in contact with a solid

heat capacity

the ability of a substance to absorb and release thermal energy with minimal change in energy

evaporative cooling

the process where, as a liquid evaporates, its remaining surface cools due to energy absorption

density

amount of mass per unit of volume

density of ice

result of hydrogen bonding in solid water, allows ice to float

solution

mixture in which one or more substances are evenly distributed in another substance

solute

a substance that is dissolved in a solution

solvent

the substance that solutes are dissolved in in a solution

hydrophobic

does not easily dissolve in water

hydrophilic

dissolves easily in water

aqueous solution

a solution where water is the solvent

acidity

relative measure of available hydrogen -1 atoms (protons) in an aqueous solution

alkalinity

relative amount of available hydroxide atoms in an aqueous solution

acid

a solution with more available protons (hydrogen) than hydroxide ions and a pH

base

a solution with more available hydroxide ions than protons (hydrogen) and a pH >7

neutral

solution with an equal amount of available hydrogen and hydroxide and a pH of 7

pH scale

logarithmic scale used to compare concentrations of single protons and hydroxide in an aqueous solution

buffers

compounds within the body that neutralize small amounts of ingested acids or bases

organic compounds

molecules made with carbon and primarily found inside living things

inorganic compounds

molecules that generally do not have carbon and are not found in living things

carbon

element that makes up organic compounds and can form up to 4 covalent bonds, the Swiss Army knife element that can bond with itself

single bond

covalent bond with one shared pair of electrons

double bond

covalent bond with two shared pairs of electrons

triple bond

covalent bond with three shared pairs of electrons

functional group

a cluster of atoms attached to an organic compound that helps determine its properties and can help identify molecules

monomer

small, simple molecule unit of an organic compound

polymer

long chain of simpler monomers attached to each other

macromolecule

a large organic polymer consisting of identical or similar monomers that plays an important role in biology

condensation reaction/dehydration synthesis

a reaction where two monomers connect, releasing a water molecule in the process

hydrolysis reaction

a reaction where a monomer is separated from a polymer by a water molecule

adenosine triphosphate (ATP)

5-carbon sugar ring and nitrogen base attached to 3 phosphate groups that is living things' way of transporting energy

carbohydrates

organic molecules that serve as short-term energy storage, made of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio

monosaccharide

monomer unit of carbohydrates, usually a carbon ring with hydrogen and oxygen attached, link together to form di- and polysaccharides

disaccharide

a carbohydrate formed by two monosaccharides linked by either an oxygen or OH group

polysaccharide

a carbohydrate formed by many monosaccharides linked by either an oxygen or OH group

isomers

molecules with the same chemical formula but a different structure and different properties

glycosidic bond

a covalent bond between monosaccharides

glycogen

carbohydrate composed of hundreds of glucose molecules linked in a branched chain to store energy in muscle and liver tissue in animals

protein

organic molecules that serve many functions in living things and are made up of carbon, hydrogen, oxygen, and nitrogen

amino acids

20 kinds of monomer units that make up proteins, all share similar structure and are differentiated by their R-group

dipeptide

two amino acids covalently bonded

polypeptide

long chain of amino acids that bends and folds based on the R-groups of the amino acids

enzyme

a special kind of protein, a biological catalyst

lipid

large, nonpolar, organic molecules used for long-term energy storage and made of carbon, hydrogen, and oxygen

fatty acid

unbranched carbon chain attached to a carboxyl group, makes up most lipids

tryglycerides

molecule composed of three fatty acid molecules joined to a glycerol molecule

saturated fat

lipid where every carbon is single bonded to four other molecules

unsaturated fat

lipid where not every carbon is single bonded to four other molecules

phospholipid

a molecule of glycerol with two nonpolar fatty acids (hydrophobic tail) and a polar phosphate group (hydrophilic head)

waxes

structural lipid with a long fatty acid joined to a long alcohol chain

steroid

lipid composed of four carbon rings with functional groups attached, most animal hormones

nucleic acids

very large, complex organic molecules that store and transfer information within cells made of carbon, hydrogen, oxygen, nitrogen, and phosphorous

nucleotide

monomer unit of nucleic acids made of a phosphate group, a 5-carbon sugar ring, and a nitrogenous base

nitrogen bases

adenosine, thymine/uracil, cytosine, guanine

DNA

nucleic acid that contains info that directs cell function

RNA

nucleic acid that stores and transfers info for creating proteins

function of carbohydrates

short term energy storage, cell structure

function of proteins

structure, movement, catalyze reactions, activate and deactivate DNA, cell signaling

function of lipids

long-term energy storage, cell membrane structure, protection/insulation, cell signaling

function of nucleic acids

store and transmit information within a cell

phospholipids

the main component of cell membranes that self-assembles into simple membranes

membrane fluidity

the cell membrane can move and bend to let some things through but not others

cholesterol

molecule found in the cell membrane and maintains membrane fluidity

glycolipid and glycoproteins

phospholipid or protein with sugar chain attached that are only found outside the membrane

functions of glycolipids and glycoproteins

sticks to other cells, receives hormone messages, cell-cell signaling, cell "fingerprint"

channel protein

s protein that allows passage of molecules or ions through membrane

carrier protein

a protein that selectively interacts with and attaches to specific molecules

cell recognition protein

a protein that identifies the cell as part of the organism