EXAM 1 Flashcards
Element
pure substance containing only one atom
All living organisms have
H,C,N,O,P,S
Atomic mass
protons + neutrons
Isotopes
forms element with differ mass numbers
Radioisotopes
unstable, give off gamma, beta, and alpha radiation)
Radioactive decay
transforms the atom
What determines how atom acts
energy, electron
Molecule
two or more bonded atoms
Chemical bond
force that links together forming molecules
Covalent Bond
sharing of e- (strongest bond)
Compound
2 or more elements
Electronegativity
attractive force that an atomic nucleus exerts on e-
Ions
electrically charged particles
Cation
positively charged
Anion
negatively charged
Ionic bond
bond btwn negative and positive ions
Cohesion
water molecules resist coming apart from 1 another (results in surface tension)
Mole
amount of substance
Avogadro’s number (1 mole)
6.02*10^23
Acids
give off H+
Bases
accept H+ ions
Weak acid
not full dissociation
Strong acid
complete dissociation
pH
log of the molar conc. of H+ ions
Lower pH means what?
H+ conc. is higher, or greater acidity
Buffer
mixture of weak acid and its corresponding base
Macromolecules
polymers with molecular weight > 1000Da
Four macromolecules
proteins, carbs, lipids, nucleic acids
Polymers of smaller molecules
monomers
LIPIDS ARE NOT POLYMERS
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Isomer
molecules that have same formula but differ. atom arrangement
Polymers formed in which reactions
condensation/dehydration
MONOMERS ARE JOINED BY COVALENT BONDS
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Functions of proteins
enzymes, structure, protection, signal transduction, transport, DNA regulation
Polypeptide chain
single, unbranched chain of AA
Argine, Histidine, Lysine
hydrophilic (form H bonds)
Negative charge
Aspartic, Glutamic
Disulfide bond
capable of stabilizing 3-D shape