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Biology 101 - Chapter 02
Biology 101 - Chapter 02 Essential Chemistry
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Biology
Undergraduate 1
09/27/2013

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Term
matter
Definition
anything that occupies space and has mass
all organisms and everything around themcan be found in three physical states:
solid, liquid, gas
Term
element
Definition
substance that cannot be broken down into other subtances by chemical reactions
92 naturally occurring elements

ex: carbon, oxygen, gold
Term
trace elements
Definition
required in only ver small amounts, but you cannot live without them

Iodine only needed in small amounts but it prevents goiters.
ex: iodine, fluorine
Term
compounds
Definition
two or more elements ina fixed ratio

ex: table salt and water
Term
atom
Definition
smallest unit of matter that still retains the properties of an element
Term
proton
Definition
subatomic particle with a single unit of positive electrical charge

located in the nucleus
mass is very similar to a neutronbut is biggest
Term
electron
Definition
subatomic particle with a single negative charge

located outside the nucleus and orbits around the nucleus
Term
neutron
Definition
electrically neutral

located in the nucleus
mass is very near the proton but slightly smaller
Term
nucleus
Definition
core of an atom
Term
atomic number
Definition
number of protons in an atom
Term
mass
Definition
measure of the amount of material in an object
Term
mass number
Definition
sum of the number of protons and neutrons in its nucleus
Term
isotopes
Definition
forms of an element that differ in mass.
elements that have the same number of protons and electrons, but different numbers of neutrons
Term
radioactive isotope
Definition
one in which the nucleus decays spontaneously, giving off particles and energy

Used in PET scanners and used as tracers, monitoring the fate of atoms in living organisms
Term
chemical bonds
Definition
transferring or sharing of outermost electrons between two atoms
ionic, covalent and hydrogen bonds
Term
ionic bonds
Definition
held together by the attraction between oppositely charged ions by transferring electrons from one atom to another
Term
covalent bond
Definition
forms when two atoms share one or more pairs of outer-shell electrons

strongest of the various bonds
Term
hydrogen bond
Definition
unequal sharing of electrons between oxygen and hydrogen atoms forming a polar molecule
Term
ion
Definition
atoms or molecules that are electrically charged as a result of gaining or losing electrons
Term
Elements essential to people
Definition
Of the 25 elements essential to people... these 4 make up 96% of the weight of most cells.
Carbon
Hydrogen
Nitrogen
The remaining 4% is made up of Calcium, Phosophorus and 14 Trace elements such as:
Iodine
Fluorine
Term
Chemical properties of atoms
Definition
Electrons vary in the amount of energy they possess. The farther they are from the nucleus the greater its energy.
Term
chemical reactions
Definition
cells constantly rearranging molecules by breaking existing chemical bonds and forming new ones
Term
reactants
Definition
starting molecules before a chemical reaction
Term
products
Definition
molecules of a chemical reaction that are arranged differently than prior to the chemical reaction
Term
cohesion
Definition
tendency ofolecules of the same kind to stick together

much stronger for water than for most other liquids
Term
heat
Definition
the amount of energy associated with the movement of atoms and molecules in a body of matter
Term
temperature
Definition
measures the intensity of heat, the average speed of molecules
Term
Properties of water
Definition
Cohesive nature of water
Ability of water to moderate temperature
Biological significance of ice floating
Versatility of water as a solvent
Term
Cohesion
Definition
tendency of molecules of the same kind to stick together
Term
Surface tension
Definition
measure of how difficult it is to stretch or break the surface of a liquid
Term
Evaporative cooling
Definition
surface of liquid remaining cooling after a substance evaporate (hottest ones vaporize first)
Term
solution
Definition
liquid consisting of a homogenous mixture of two or more substances
Term
solvent
Definition
dissolving agent
Term
solute
Definition
any substance that is dissolved
Term
aqueous solution
Definition
when water is used as the solvent
Term
acid
Definition
chemical compound that releases H+ to a solution
Term
base
Definition
compound that accepts H+ and removes them from solution
Term
pH scale
Definition
measure of hydrogen ion (H+) concentration in a solution
Term
buffers
Definition
contained in biological fluid and minimizes changesin pH by accepting H+ when that ion is in excess and donating H+ when it is depleted
Term
Hydrogen bonds of water
Definition
Positive and negative poles cause adjacent water molecules to become attracted to each other. ALL properties of water arise from this atomic stickiness
Term
Van der Waals interactions
Definition
attractions between molecules that are close together due to electrons being distributed assymetrically in molecules or atoms, resulting in "hot spots" of negative or positive charge
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