Ap Bio Unit 1 vocab

atom

atom

the smallest unit of an element that maintains the properties of that element.

chemical equilibrium

when forward and reverse reaction rates are in balance.

covalent bond

the sharing of a pair of valence electrons by two atoms.

electron shell

a circle(s) of electrons surrounding a nucleus.

element

a substance that cannot be broken down into simpler substances.

ionic bond

a chemical bond resulting from the attraction between oppositely charged ions.

molecule

two or more atoms held together by covalent bonds.

product

a substance produced in a chemical reaction.

valence shell

outermost electron shell.

atomic mass

number of protons and neutrons.

compound

a substance made up of atoms of two or more different elements joined by chemical bonds.

dalton

a measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu.

electronegativity

a measure of the ability of an atom in a chemical compound to attract electrons.

geometric isomer

differ in arrangement around a double bond - cis/trans.

isotope

atoms of the same element that have different numbers of neutrons.

potential energy

stored energy.

reactant

a substance that takes part in and undergoes change during a reaction.

van der Waals interactions (end of chapter 2)

individually weak and occur only when atoms and molecules are very close together.

acid

a substance that increases the hydrogen ion concentration of a solution.

base

a substance that decreases the hydrogen ion concentration in a solution.

calorie

amount of energy needed to raise temperature 1 gram of water 1 degree C.

evaporative cooling

process of when the surface of an object becomes cooler during evaporation, since the molecules with the greatest kinetic energy change from the liquid to the gaseous state.

hydrogen ion

H+

hydroxide ion

OH-

molarity

moles of solute/liters of solution.

ester bond

a dehydration bond between a hydroxyl group and a carboxyl group.

solvent

a liquid substance capable of dissolving other substances.

adhesion

an attraction between molecules of different substances.

buffer

a solution that minimizes changes in pH when external acids or bases are added to the solution.

cohesion

attraction between molecules of the same substance.

heat of vaporization

the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state.

hydrophilic

attracted to water.

kinetic energy

energy of motion.

mole

the SI base unit used to measure the amount of a substance.

solute

substance being dissolved into another substance.

specific heat

the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celsius.

ATP

(adenosine triphosphate) main energy source that cells use for most of their work.

carboxyl group

a functional group present in organic acids consisting of a carbon atom double-bonded to an oxygen atom and singly bonded to an oxygen atom and a hydrogen and acts as an acid.

functional group

a specific arrangement of atoms commonly attached to the carbon skeletons of organic molecules and are involved in chemical reactions.

hydrocarbon

an organic molecule consisting only of carbon and hydrogen.

isomer

compounds with the same formula but different structures.

phosphate group

PO4; attaches to a molecule and allows it to react with water.

sulfhydryl group

a chemical group consisting of a sulfur atom bonded to a hydrogen atom; stabilizes proteins.

carbonyl group

a chemical group consisting of a carbon atom linked by a double bond to an oxygen atom; found in ketone groups.

enantiomer

isomers that are mirror images of each other.

ester linkage

a dehydration bond between a hydroxyl group and a carboxyl group.

hydroxyl group

a chemical group consisting of an oxygen atom bonded to a hydrogen atom; is polar and helps to dissolve compounds.

methyl group

a chemical group consisting of a carbon atom bonded to three hydrogen atoms; affects genes and hormones.

structural isomer (end of chapter 4)

one of several compounds that have the same molecular formula but differ in the covalent arrangements of their atoms.

amino acid

building blocks of protein molecules; an organic molecules with an amino group and carboxyl group bonded.

carbohydrate

sugars and polymers of sugars; monosaccharides.

cellulose

a substance (made of sugars) that is common in the cell walls of many organisms.

cholesterol

steroid common in cell membranes, also in many hormones.

DNA

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main component of chromosomes. it is the carrier of genetic information.

enzyme

a type of protein that speeds up a chemical reaction in a living thing.

glycogen

a polysaccharide found in the liver and muscles.

hydrolysis

the chemical breakdown of a compound due to reaction with water.

hydrophilic

attracted to water.

macromolecule

a very large organic molecule composed of many smaller molecules.

nucleic acid

DNA and RNA, a molecule made up of subunits called nucleotides.

peptide bond

covalent bond formed between amino acids.

phospholipid

a molecule that's a component of the inner bilayer of biological membranes. having a polar (hydrophilic head) and a nonpolar (hydrophobic tail).

protein

an organic compound that is made of one or more chains of amino acids and that is a principal component of all cells.

pyrimidine

a nitrogenous base with a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine, or uracil.

starch

a storage polysaccharide in plants consisting entirely of glucose.

amino group

a chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; acts as a base.

catalyst

substance that speeds up the rate of a chemical reaction.

chitin

a carbohydrate that is tough and flexible.

dehydration reaction

a chemical reaction in which molecules combine by removing water.

disulfide bridge

two cysteine amino acids form a covalent bond during the folding of the protein.

gene

sequence of DNA that codes a protein which determines a trait.

glycosidic linkage

a covalent bond formed between two monosaccharides by a dehydration reaction.

hydrophobic

having a dislike to water; tending to join and form droplets in water.

lipid

macromolecules made mostly from carbon and hydrogen atoms; includes fats, oils, and waxes.

monomer

a simple compound whose molecules can join together to form polymers.

nucleotide

monomer of nucleic acid made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

phosphodiester bond

the type of bond that links the nucleotides in DNA or RNA. joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide.

polymer

a long molecule consisting of many similar or identical monomers linked together.

purine

double ring, adenine and guanine.

RNA

ribonucleic acid; a nucleic acid that plays an important role in the production of proteins.