chapter two Flashcards
the chemical context of life
matter
anything that takes up space and has mass
mass
amount of matter
elements
any substance that cannot be broken down to any other substance by chemical reactions
what are the essential chemicals of life?
C,H,O,N
why are the essential chemicals of life needed?
required for an organisms to survive, grow, and reproduce
compounds
a substance consisting of two or more different elements combined in a fixed ratio
atom
smallest unit of matter that still remains the properties of an element
charge of proton?
positive, found in nucleus
charge of neutron?
neutral, found in nucleus
charge of electron?
negative (no mass), found on orbital rings
the atomic number is also the number of ______ in that element?
protons
protons + neutrons = ?
mass
isotope
element with different number of neutrons
half life
time it takes for half of isotope to decay
ground state
when electrons are close to nucleus and have less energy
excited state
when electrons are far from nucleus and have lots of potential energy
covalent bonds
SHARE electrons
ionic bonds
electrons are completely given or taken
hydrogen bonds
between two poler molecules (weak bond), bond between a positive ion on one molecule and a negative ion on another molecule
van der waals interactions
very weak attraction between two non polar molecules
shape recognition
enzymes match substrate cell surface markers and receptors
endergonic
requiring the absorption of energy, store and build
exergonic
release of energy, breaking
radioactive dating
method of dating rocks and minerals using radioactive isotopes, decay at a constant rate
