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ch.2
ch.2
80
Biology
Undergraduate 1
03/25/2008

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Term
organisms are composed of ___, which is anything that takes up space and has mass
Definition
matter
Term
anything that takes up space and has mass
Definition
matter
Term
___ is made up of elements
Definition
matter
Term
is a substance that cannont be broken down to other substances by chemical reactions
Definition
element
Term

__ is a substance consisting of two or more different elements combined in a fix ration

Definition
compound
Term

what is this example of: pure sodium is a metal and pure chlorine is a poisonous gas. When combined chemically sodium and chloride form an edible compound.

Definition
examples of organized matter having emergent properties
Term
__ is a compound that has characteristics different from those of its elements
Definition
emergent properties
Term
identify the 4 elements that make up 96% of living matter?
Definition
carbon, oxygen, hydrogen and nitrogen
Term
what other elements make up 4% of an organisms weight?
Definition
phosphorous, sulfur, calcium and potassium
Term
 are those required by an organism in only minute quantities.
Definition
trace elements
Term
what is this an example of: in vertebrates, the element iodine is an essential ingredient of a hormone produced by the thyroid gland. A daily intake of only 0.15miligrams of iodine is adequate for normal activity of the human thyroid. An iodine deficiency in the diet can cause thyroid to grow to abnormal size
Definition
trace element
Term
each element consists of a certain kind of _ that is different from the atoms of any other element
Definition
atom
Term
is the smallest unit of matter that still retains the properties of an element
Definition
atom
Term
although an atom is the smallest unit having the properties of its elements, these tiny bits of matter are composed of even smaller parts called
Definition
subatomic particles
Term
what three kinds of particles are relevent in an atom
Definition
neutrons, protrons and electrons
Term
_ and _ are electrically charged
Definition
protons and electrons
Term
each _ has one unit of positive charge
Definition
proton
Term
each _ has one unit of negative ceharg
Definition
electron
Term
_ are nuetral
Definition
nuetrons
Term
what make up the atomic nucleus?
Definition
protons and nuetrons
Term
__ form a cloud of negative charge around the nucleus
Definition
electrons
Term
 what keep the electrons in the vicinity of the nucleus?
Definition
attraction between opposite charges.
Term
the nuetron and proton are almost identical in mass,each about 1.7x10-24g.grams and other conventional units are not useful for describing the mas of objects so miniscule. Thus for atoms and subatomic particles, __ is used
Definition
dalton
Term
the number of protons is called ( and located bottom left of the symbol)
Definition
atomic number
Term
__tells the number of protons and electrons
Definition
atomic number
Term
number of nuetrons can be found from
Definition
mass number
Term
sum of protons and neutrons
Definition
mass number
Term

 _____the atom’s total mass, can be approximated by the mass number.

Definition
atomic mass
Term

The __ is the sum of the number of protons and neutrons in the nucleus of an atom.Therefore, we can determine the number of neutrons in an atom by subtracting the number of protons (the atomic number) from the mass number.

 

Definition
mass number
Term

__of an atom, a measure of its mass, can be approximated by the mass number.

For example, 4He has a mass number of 4 and an estimated __ of 4 daltons.
Definition
atomic weight
Term

two atoms of the same element that differ in the number of neutrons are called

Definition
isotopes
Term

Most isotopes are __; they do not tend to loose particles.Both 12C and 13C are__ isotopes.

Definition
stable
Term

The nuclei of some isotopes are unstable and decay spontaneously, emitting _and _.14C is a one of these _or _ isotopes.

  1.  

         

  2. When 14C decays, a neutron is converted to a proton and an electron.

         

         

  3. This converts 14C to 14N, changing the identity of that atom.

         

         

           

Definition

particles and energy

unstable or radioactive isotopes

Term
__ is one in which the nucleus decays spontaneously, giving off energy and particles
Definition
radioactive isotopes
Term
radioactive isotopes have many applications in biological research:
Definition

1. radioactive decay rates can be used to date fossils

2. can be used to trace atoms in metabolisms

3. can be used to diagnose medical disorders

Term
is the ability to do work or the capacity to cause change
Definition
energy
Term
_is the energy that matter stores because of its position or location
Definition
potential energy
Term
electrons of an atom _ in their amounts of poetential energy
Definition
differ
Term
an electrons's state of potential energy is called
Definition

energy level or electron shell

Term
The farther electrons are from the nucleus, the __ potential energy they have.

 

Definition
more
Term
  •  Changes in potential energy can only occur in steps of a __, moving the electron to a fixed location.
  • An __ cannot exist between these fixed locations

     

Definition

fixed amounts

electron

Term

_ cannot occupy just any location away from the nucleus

Definition
electrons
Term
which has the lowest energy level or electron shell? which has the highest?
Definition

-electrons in the first shell closest to the nucleus has the lowest potenital energy

-electrons in the outer shell have more potential energy

Term
electrons can only change their position if they?
Definition
absorb or release a quantity of energy that matches the difference in potential energy between the 2 levels
Term
the chemical behavavior of an atom is determined by its
Definition
electron configuration
Term
_ is the distribution of electrons in its electron shell
Definition
electron configuration
Term
the chemical behavior of an atom deprends mostly on the?
Definition
the number of electrons in its outermost shell, the valence shell
Term
electrons in the valence shell are known as
Definition
valence electrons
Term

*atoms with complete valence shell are __

*all other atoms are __ because they have incomplete valence shells

Definition

unreactive

chemically reactive

Term
atoms with incomplete valence shells interact by either
Definition
sharing or transferring valence electrons
Term
atoms with incomplete valence shells interact by either sharing or transferrig valence electrons. These interactions typically result in the atoms remaining close together held by an interaction called
Definition
chemical bonds
Term
is the sharing of a pair of valence electrons by two atoms
Definition
covalent bond
Term
_ consists of two or more atoms held together by covalent bonds
Definition
molecule
Term

We can abbreviate the structure of a molecule by substituting a line for each pair of shared electrons,drawing the __.

 

H-H is the _  for the covalent bond between two hydrogen atoms.

Definition
structural formula
Term

The __ indicates the number and types of atoms present in a single molecule.

Ex. H2 is the __for hydrogen gas.

 

Definition
molecular formula
Term

In a ___bond, the atoms share the electron equally.

Definition
nonpolar covalent bond
Term

In a __ one atom is more electronegative, and the atoms do not share the electron equally.

Definition
polar covalent bond
Term
a charged atom or molecule is called an
Definition
ion
Term
_ is an attraction between anions and cations
Definition
ionic bond
Term

atoms with postive charge called_

atoms with negative charge called

Definition

cations

anions

Term
compounds formed by ionic bonds are __ or __ like NaCl or table salt
Definition
ionic compounds or salts
Term
the formula for an __ indicated the ratio of elements in a crystal of that salt
Definition
ionic compound
Term
most of the strongest bonds in organisms are __ that for a cell's molecules
Definition
covalent
Term
weak chemical bonds such as _ and _ are also important
Definition
ionic and hydrogen bonds
Term

__ reinforce shapes of large molecules and help molecules adhere to each other

Definition
weak chemical bonds
Term
in living cells, the electronegative partners are usually?
Definition
oxygen or nitrogen atoms
Term
molecules or atoms that are very close together can be attracted by
Definition
fleeting charge differences
Term
weak attractions are called
Definition

van der waals interactions

Term
a molecule's shape is usually very important to its
Definition
function
Term
a molecule's shape is fetermined by the postion of
Definition
its atoms's valence orbitals
Term
for atoms with electrons in both s and p orbitals, the formation of covalent bonds leads to hybridization of the orbitals to four new orbitals in a
Definition
tetrahedron shape
Term
biological molecules recognize and interact with each other with a specificity based on
Definition
molecular shape
Term
molecules with similar shapes can have similar
Definition
biological effects
Term

for example, morphine, heroin and other opiate drug similar enough in shape that they can bind to the same receptiors as natural signal molecules called___

Binding to receptors produces

Definition

endorphins

euphoria and relieves pain

Term

Photosynthesis is an important chemical reaction.

green plants combine with water from the air and water from the soil to create __

* this chemical reaction is powered by__

Definition

sugar molecules and molecular oxygen, a byproduct 

*sunlight

Term
humans and other animals depend on photosynthesis for _
Definition
food and oxygen
Term

the overall process of _ is

6CO2 +6H20 goes to C6H1206 +602

* this process occures in

Definition

*photosynthesis

*sequence of individual chemical reactions

Term

*some chemical reactions go to completions_

 

Definition
all reactants are coverted into products
Term
most chemical reactions are reversible
Definition
products of the forward reaction become reactants for the reverse reaction
Term
_ is reached when the forward and reverse reaction rates are equal
Definition
chemical equilibrium
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