charge of an atom in the elemental state
state that contains electrons in the lowest energy level
atoms of one element that vary only in the # of neutrons in the nucleus
radioactive isotope of an element
rate at which nuclei of of radioisotopes emit particles and decay
radioactive carbon isotope incorporated in molecules of carbon dioxide and used to track metabolic pathways
bond formed between atoms when electrons are transferred
atom that gains electrons when an ionic bond is formed (negative)
atom that loses electrons when an ionic bond is formed (positive)
bond formed between atoms when electrons are shared
result of a covalent bond
bonding that occurs between two molecules containing atoms that exert a strong pull on their electrons
"water hating" or "repelled by water"
"water loving" or "attracted to water"
"like dissolves like"
Why will a nonpolar substance not dissolve in a polar substance (such as water) or vice versa?
a measure of acidity and alkalinity of a solution
Each number on the pH scale denotes a pH that is ____ times more acidic or basic than the one before.
substance that resists change in pH
most important buffer in human blood
function of carbohydrates
supply quick energy
compounds w/ the same molecular formula but different structures ---> different physical and chemical properties
process by which two monosaccharides are joined by the removal of a molecule of water
breakdown of a compound; the reverse process of dehydration synthesis
polymers of carbohydrates
makes up plant cell walls
form of carbohydrate storage for plants
makes up the exoskeleton in arthropods and cell walls in mushrooms
"animal starch"; in humans, stored in the liver and skeletal muscle
cellulose, starch, chitin, glycogen
four important polysaccharides
saturated fatty acids
fatty acids that contain only single bonds between carbon atoms
unsaturated fatty acids
fatty acids that have at least one double bond between carbon atoms in the hydrocarbon chain
functions of lipids
energy storage, structural, endocrine
polymers or polypeptides consisting of repeating units (amino acids) joined by peptide bonds
repeating units that make up proteins
bonds that link amino acids in a protein
polymers of amino acids
composition of an amino acid
carboxyl group, amino group, and a variable (R) group, all attached to a central carbon atom
function of proteins
responsible for growth & repair
S, P, C, O, H, N
elements that make up proteins
How many different amino acids exist?
2 amino acids joined together by a peptide bond
protein structure that results from the sequence of amino acids that make up the protein chain
protein structure that results from H bonding within the molecule
protein structure that is 3-D shape (conformation) of protein and most directly determines the way it functions and its specificity
the process by which an enzyme loses its natural shape
protein structure that consists of more than one polypeptide chain
large proteins that speed up reactions
energy of activation
amount of energy needed to begin a reaction
chemical that an enzyme works on
as the substrate enters the active site, it induces the enzyme to alter its shape slightly
Are enzymes reusable?
mineral substance that assists enzyme
vitamin substance that assists enzyme
temperature & pH
factors that affect efficiency of an enzyme
infectious proteins that cause several brain diseases; misfolded version of a protein found in mammalian brains that, upon getting into a normal brain, causes all normal proteins to misfold in the same way
Deoxyribonucleic acid (DNA ) & ribonucleic acid (RNA) are the.....
phosphate, 5-carbon sugar, nitrogenous base
adenine & guanine
The purines are...
cytosine, thymine, uracil
The pyrimidines are...
A, T, C, G
nitrogenous bases in DNA
A, U, C, G
nitrogenous bases in RNA
chain of repeating units
polymer of nucleotides
Water has a ______ specific heat.
Water has a ______ heat of vaporization.
heat of vaporization
amount of heat needed to evaporate liquid
amount of heat that must be absorbed for 1 gram of a substance to change its heat 1 degree Celsius
Ice is _____ dense than water.
universal solvent (dissolves all polar & ionic molecules)