Chemistry of Life

define “element.”

a pure substance comprised of atoms of only 1 type

_____ are made up of “building blocks” of elements

molecules

what are “bulk elements?”

the 13 most abundant elements in the body

what are the top three bulk elements?

oxygen, carbon, and hydrogen

what are “trace elements?”

14 elements found in the body in trace amounts

define an atom.

the smallest structural unit that maintains the properties of that element

what is an atomic number?

number of protons in the nucleus of an atom

• unique to each atom (how we know what element it is)

what is a mass number?

number of protons + number of neutrons

• may be decimal bc it’s the average of all mass and some have more neutrons

the first e- shell requires ____ e- to be full; the rest require ____

2, 8

what is the state of an atom with a not full e- shell?

reactive

what is the state of an atom with an e- shell that is full?

inert (ideal)

elements in the last column of the PT are known as what?

the Noble Gases

define an ion.

an atom that has a charge associated with it

• either gives up or accepts an e- to become more stable or electrically charged

what is an ion that is positively charged?

a cation (Na)

what is an ion that is negatively charged?

an anion (Cl)

define a “molecule.”

particle formed when two or more atoms chemically combine through bonding

define “electronegativity.”

the force/attraction an e- has for a particular atom

• the ability of an atom to attract e-

define an ionic bond.

a bond that is formed by electrostatic attraction of ions with opposite charge

define electrostatic attraction.

the pulling force that happens between two objects or particles with opposite electrical charges

describe a covalent bond

when multiple atoms come together and share e-

• intermolecular

in what type of covalent bonds are e- shared equally?

non-polar

• ex: hydrogen molecule

in what type of covalent bond are e- shared unequally?

polar

• ex: water molecule

describe a hydrogen bond.

covalent bond formed by attraction between positive H end of polar molecule + a negative N, O, or F end of another polar molecule

what are hydrogen bonds commonly used for in the body?

in DNA and proteins.

define solvent.

sol’n component into which solute dissolves

define solute.

sol’n component which is dissolved into solvent

define an aqueous sol’n.

a solution in which water is the solvent

define solubility.

the ability of a solute to dissolve

• depends on the molecule’s charge

what is the key characteristic of a homogenous mixture.

there is the same # of solutes throughout the sol’n

define an electrolyte.

an ionized sol’n

what does the prefix “milli” mean?

10^-3

define Molarity

• moles/Liter

• describes # of molecules

define Osmolarity

• Osmoles/Liter

• M x # of particles it dissolves into

Define an osmole

the number of particles into which a solute dissociates in solution

how to calculate % of solute concentration?

grams of solute / 100 mL solvent

How is the concentration of ions measured?

in equivalents

what is an equivalent?

the # of moles of ionized solute x valence of the ion

• equivalents/Liter

• charge doesn’t matter, just #

define valence

the charge of an ion

what percent of body weight is TBW?

60%

what are the factors that influence TBW?

• state of hydration

• sodium balance

• individual bodies

what is TBW distributed to?

• 40% intracellular fluid (ICF)

• 20% extracellular fluid (ECF)

what is the composition of ECF?

• 75% interstitial fluid

• 25% plasma

define interstitial fluid.

fluid in tissues and organs that surrounds cells

define plasma.

fluid of blood

____ ____ and ____ are permeable to water.

cell membranes, capillaries

what is the primary function of capillaries?

transfer stations

define an acid and its role with H ions.

solute that dissociates in solution and releases hydrogen ions

• adds H ion

• proton donor

define a base and its role with H ions.

solute that removes H ions from solution

• H ion remover

what type of scale is a pH scale?

logarithmic

what do pH scales measure?

the concentration of H ions

the presence of H ions and the pH value have a ____ relationship?

inverse

pH =

- log [H⁺]

what is normal range of blood pH?

7.35 - 7.45

what is a pH > 7.45 defined as?

alkalosis

what is a pH < 7.35 defined as?

acidosis

why is a skewed blood pH bad?

it messes up the ability of hemoglobin to carry oxygen