A&P Ch 2 Flashcards
the chemistry of life
element
simplest form of matter to have unique chemical properties ex. Na+, H, O, K
major elements
CHNOPS 98%
CHNOPS
carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur
lesser and trace elements
Fe, Si, As, Mg2+, Cu2+
minerals
make up 4% of the body. Ca & P are most abundant, present in bones in the body. minerals originate primarily in soil and plants. function as coenzymes
atom
smallest unit that retains the properties of an element. composed of 3 subatomic particles
neutrons
neutral charge, heavy
protons
positive charge, heavy = # of electrons
atomic number
name of element
atomic mass
protons + neutrons
atomic weight
average of atomic mass of all forms of an element
molecular weight
sum of all atomic weights
electrons
negative charge, very light, form a cloud around the nucleus
distribution of electrons
in a specific energy shell/level. 1st shell hold 2, remaining shells hold 8.
bohr models
represent electron distribution
valence electrons
the electrons in the outer most shell, the number of valence electrons dictates the reactivity of an element, atoms are most stable when the valence shell is full, 2 in the first and 8 in the second. will react with other atoms to fill their outermost shell
isotopes
different forms of one elemnt that vary in the number of neutrons present
radioisotopes
unstable isotopes, nucleus decays spontaneously, giving off particles and high energy
ionizing radiation
energy that ejects electrons from atoms. creates ions that are carcinogenic. damages molecules. ex. UVrays, Xrays
ions
charged particles with unequal numbers of protons and electrons. can be a single atom or a group of atoms
cation
positive charge
anion
negative charge
electrolytes
ionize in h2o (acids, bases, salts), form solutions capable of conducting electricity. they conducts electrical currents from organs to skins surface. if they are imbalanced that can cause muscle cramps, brittle bones, coma, cardiac arrest
free radicals
chemical particles with an odd number of electrons. they come by some normal metabolic reactions of the body, radiation, chemicals. they can cause cancer, myocardial infarction (death of heart tissue)
atioxidant
a chemical that neutralizes free radicals. some examples are selenium, vitamin e, vitamin c, cartenoids
molecule
2 or more atoms joined by a covalent bond
compound
molecules composed of 2 or more different elements
molecular weight
sum of the atomic weights of all atoms
chemical bonds within molecules
ionic bonds, covalent bonds, nonpolar covalent, polar covalent
ionic bond
attraction of a cation to an anion. not very strong. ex. Na+Cl-
covalent bond
2 atoms share electrons. very strong, solid, straight line. ex. C-C, O=O, C-H
nonpolar covalent bond
equal sharing of electrons. ex. O=O, C-C, C-H
polar covalent bond
unequal sharing of electrons. ex. H-O-H
chemical bonds between molecules
hydrogen bond, van der waals forces
hydrogen bond
form between a hydrogen bonded to an electronegative atom and an electronegative atom of another molecule. ex. … = hydrogen bond
van der waals forces
interactions between electrons of one molecule and nucleus of another. holds DNA nucleotides together, holds lizards to ceilings
mixture
physically mixed, but not chemically combined
water
H & O within a water molecule are bond together with polar, covalent bonds. H is bound to O from another molecule by hydrogen bonds
properties of water
solvency, adhesion, cohesion, chemical reactivity, thermal stability
solvency
many compounds dissolve in water. essential for transport of molecules throughout the body
hydrophillic
compounds dissolve in water
hydrophobic
compounds are not soluble in water