Basic Chemistry

 your entire body is made up of chemicals
 chemical processes underlie all body
processes
 the food you eat, the medicines you take,
it’s all chemistry!

 chemistry: the science that deals with the
composition and properties of substances and
various elementary forms of matter.
 biochemistry: the chemistry of living
material

 matter: anything that has mass and takes
up space
 it is the “stuff” of the universe
 chemistry studies the nature of matter

 three main states of matter
 1. solid – definite shape, definite volume
 2. liquid – no definite shape, definite volume
(fits to the size of its container)
 3. gas – no definite shape, no definite volume
(expands to fill available space)

 Bodily examples:
 1. solid – bones, teeth
 2. liquid – blood, urine
 3. gas – air, digestive byproducts

 Element: substances that cannot be broken
down into simpler substances
 Can you name some examples?
 (Please say yes!)

 A complete listing of all the elements
appears in the Periodic Table
 It is called periodic because it repeats
 The modern Periodic Table was developed in
1869 by a Russian scientist named Dimitri
Mendeleev

 A vertical column is called a group or a
family
 These groups usually contain the same number of
valence electrons
 A horizontal row is called is called a period
or a series
 These periods show similarities in ionization and
activation energy

 On the left hand side are the metals
 Usually solid, shiny, good conductors of heat and
electricity
 On the right hand side are the non-metals
 Usually gaseous, dull, poor conductors of heat
and electricity
 In the diagonal space between metals and
non-metals are the metalloids
 Some characteristics of both metals and non-
metals

 Review: (fingers crossed here)
 All elements are made up of only one type of
atom
 Atom: the smallest part of an element,
indivisible by normal chemical means

 Every atom is composed of three types of
subatomic particles:
 1. Protons (P+) positively charged, found in
the nucleus, has mass
 2. Neutrons (N0) neutrally charged, found in
the nucleus, has mass
 3. Electrons (E-) negatively charged, found
outside the nucleus, had negligible mass

 The Chemical/Elemental Name of the
element is given
 The abbreviated symbol related to the name
of the element is called the
Chemical/Elemental symbol

 The atomic number is the number of
electrons
 And in a balanced atom, the number of
electrons is equal to the number of protons
 Think here, - = + means no charge!

 Then the atomic mass is equal to the mass of
the nucleus (protons + neutrons)
 Remember, neutrons add mass but have no
charge!

 To find the number of neutrons all you must
do is:
 Atomic mass – atomic number
 (protons + neutrons) – protons = neutrons
 Easy!

 You should be able to tell me the chemical
symbol, chemical name, atomic mass, atomic
number, number of protons, neutrons and
electrons.

 Ok, so now that you are experts (or at least
not clueless) let’s try so advanced uses of the
Periodic Table

 Electrons exist outside the nucleus of the
atom and move continuously
 They are negatively charged and are always
pulled towards the positively charged
nucleus
 But they do this at different locations

 Electron shells or energy levels: the regions
in which electrons travel
 Each shell can only hold a certain number of
electrons
 The outer most level is called the valence
level and the electrons in that level are
called valence electrons

 In English,
 Level 1 = 2
 Level 2 = 8
 Level 3 = 18
 Level 4 = 32
 That’s all I will
make you learn for
now

 Because electrons are not stationary it is
important to show where they are generally
located
 In order to do this we can used either a Bohr
Diagram or a Lewis Diagram (Dot Diagram)

 Bohr Diagrams show ALL electrons in their
correct energy levels
 Let’s look at Oxygen:

 Now try Neon on your own.
Not Neon

 Does your diagram look something like this?

 Now on the other hand, a Lewis Diagram
(also called a Dot Diagram) only shows the
VALENCE electrons

 Now try Chlorine on your own

 Let’s hope yours looks like this:

 Isotopes: atoms of the same elements with a
different number of neutrons
 Therefore, they have a different atomic mass
 The mass changes but the charge does not!

 Because isotopes have the
same number of electrons
their chemical properties
are the same
 They have the same
reactivity and bonding
ability

 Radioisotopes: the heavier isotopes of
certain atoms are unstable and tend to
decompose (to become more stable)
 Radioactivity: the spontaneous decay of
radioisotopes
 The most commonly used radioisotope is C13

 Radioisotopes are used in minute amounts to
tag biological molecules so that they can be
followed throughout the body
 Valuable for medical diagnosis and treatment

http://www.youtube.com/watch?v=WFqqVpPzUaI

 matter may be changed both physically and
chemically
 physical changes do not alter the basic
nature of a substance
 ex. melting, contraction of the muscles,
blood vessel contraction

 chemical changes do alter the composition of
the substance
 ex. burning, fermenting, lactic acid
production, hormone release

 energy: the ability to do work
 massless and does not take up space

 kinetic energy: energy of motion
 potential energy: inactive or stored energy
 all forms of energy exhibit both kinetic and
potential work capacities

 Remember!
 All living things are made or matter and all
living things require a continuous supply of
energy

 1. Chemical Energy
 2. Electrical Energy
 3. Mechanical Energy
 4. Radiant Energy

 is stored in the bonds
of chemical
substances
 when the bonds are
broken, the potential
energy is unleashed
and becomes kinetic
energy
 ex. car engine
(internal combustion
engine)

 results from the movement of charged
particles
 in the house, electrical energy is the flow
through your wiring

 in your body, an
electrical current is
generated when charged
particles (ion) move
across cell membranes
 the nervous system uses
electrical currents
called nerve impulses to
transmit messages from
one part of the body to
another

 energy directly involved in moving matter
 as the muscles in your legs shorten, they
pull on your bones, causing your limbs to
move

 travels in waves
 the energy of the electromagnetic spectrum
 this includes x rays, infrared radiation,
visible light, radio, uv rays

 with a few exceptions, energy is easily
converted from one form to another

 in the body, chemical
energy of foods is
trapped in the bonds of
a high-energy chemical
called ATP (Adenosine
TriPhosphate)
 ATP’s energy may
ultimately be
transformed into the
electrical energy of a
nerve impulse or
mechanical energy of
shortening muscles

 Energy conversions are inefficient
 some of the energy supply is always “lost” to
heat

 it is not really lost but rather unusuable
 Remember, energy is neither created nor
destroyed, it only changed form
 for example, when matter is heated, the
particles move more quickly (their kinetic
energy increases)

THE BUILDING BLOCKS - MACROMOLECULES

 Organic compounds:
Molecules that contain
atoms of Carbon,
Hydrogen and usually
Oxygen
 High energy molecules, it
takes energy to make
them
 The ability to use energy
to make or synthesize
organic compounds is an
important characteristic
of all living things

 On their own, organic compounds would
break down, releasing energy
 Organisms are able to control this breakdown
in order to harness the energy released
 Most organic compounds belong to one of
four main groups: Carbohydrates, Proteins,
Lipids, Nucleic Acids

 Carbohydrates are composed mainly of just
the basic elements of other organic
molecules: carbon, hydrogen, and oxygen
 monomer: monosaccharides, polysaccharides
 Simplest one is glucose

 Most complex sugars are formed from a chain
of simple sugars
 Starches and more complex sugars consist of
very long chains that may include more than
just simple sugars

 Some carbs are structural molecules which
provide support and protection
 Ex. Chitin and cellulose
 Healthy carbs are naturally occurring sugars
 Unhealthy carbs are refined, added simple
and complex sugars
 kCals only, no nutritional value

 Made up of amino acids - 20 different a.a.
 Monomer: amino acids
 Enzymes: proteins that speed up or
catalyze, specific chemical reactions
 All enzymes are proteins but all proteins
are not enzymes
 work in enzyme-substrate complex
 enzyme is the “lock”
 substrate is the “key”

 Without enzymes, most metabolic
reactions would proceed very slowly or
not at all
 Ex. Lipases break down lipids (fats)
 Some hormones are proteins
 Ex. Insulin
 Hormones: chemicals that act as
messengers to help different parts of the
body to work together

 Four stages of Protein Folding
 1. Amino Acid strand - disulfide bridges
 2. A helix or B pleated sheets
 3. Tertiary folding - hydrogen bonding,
more disulfide bridging within the same
molecule
 4. Quaternary structure, multiple tertiary
structures joining together

 Humans can synthesize 11 of 20 a.a.
required for protein synthesis - “non-
essential a.a.”
 Remaining 9 - “essential a.a.”
 must be included in diet

 Monomers: Glycerol molecule bonded to 3
fatty acid molecules
 Lipids are often used for energy storage,
helping form membranes, and waterproofing
surfaces

 Some hormones are fats
 Ex. Steroid hormones

 Saturated Fats - “bad” fats
 no “kinks” in the chain, able to pack together
 Unsaturated Fats
 Polyunsaturated fats and monounsaturated
fats - “good” fats
 “kinks” allow fats to stay free

 Nucleic acids store and transmit the basic
genetic information of all living things
 Monomer: nucleotides
 Nucleotides consist of a simple sugar joined
to molecules containing phosphorus and
nitrogen

 One type of nucleic acid is DNA
(Deoxyribonucleic Acid)
 DNA specifies all the instructions for an
organism’s construction and maintenance

 Genome: An organism’s complete genetic
information
 The 4 nitrogenous bases of the nucleotides
are: Adenine, Cytosine, Thymine, and
Guanine
 Nitrogenous bases are like letters in a word,
and genes are like complete “words” in a
sentence

 RNA – Ribonucleic Acid
 Uracil instead of Thymine
 Many RNA molecules help
convert the genetic info
contained in DNA into
proteins - protein
synthesis
 Some RNAs catalyze
reactions like enzymes

 When two or more atoms
combine chemically
molecules are formed
 For example, when two
Nitrogen atoms bond, a
molecules of Nitrogen gas
is formed
 N + N -> N2

 In the Nitrogen example the reactants are
the substances involved in the chemical
reaction (the single Nitrogen atoms)
 The product is the substance that results
from the reaction (the Nitrogen molecule)

 A Molecular formula shows the chemical
composition or atomic makeup of a molecule
 What chemicals are in NaCl?
 Bonus points if you know what this is!

 When two or more different atoms bond
together to form a molecule, the molecule is
called a compound
 For example 2H + O -> H2O
 Thus a molecule of water is a compound

 It is important
to remember
that compounds
have properties
different from
those of the
elements of
which they are
composed

 Chemical reactions: when two or more atoms
combine with or dissociate from each other

 A chemical bond is an
energy relationship
 Bonds are directly
related to the number of
valence electrons and
the electron levels

 Remember, electrons occupy generally fixed
regions of space around the nucleus called
electron shells or energy levels
 The electrons closest to the nucleus are the
most strongly attracted and those farther
from the nucleus are less securely held

 The only electrons that
are important when
considering bonding
behavior are those in
the valence level
 When the valence level
has 8 electrons, the
atom is completely
stable and is chemically
inactive (inert)

 When the
valence shell
contains fewer
than 8
electrons, an
atom will tend
to gain, lose or
share electrons
to reach a
stable level

1. Ionic Bonds
2. Covalent Bonds
3. Hydrogen Bonds

 Ionic Bond: A chemical bond formed when
electrons are completely transferred from
one atom to another

 Atoms are electrically neutral, but when
they gain or lose electrons during bonding,
their positive and negative charges are no
longer balanced
 This creates ions or charged particles

 Polyatomic ions: Ions composed of multiple
atoms
 Ex. Ammonium NH4
+

 Anions: negatively charged ions that result
from the addition of an electron

 Cation: a positively charged ion that results
from the loss of an electron

 Both anions and cations result when an ionic
bond forms
 Because opposite charges attract, the newly
created ions tend to stay together
 Ex. Sodium chloride (Table Salt)

 Salts: are ionic compounds that result from
the neutralization of an acid and a base
 They are composed of a cation and an anion
so the resulting product is neutral

 Electrons do not need to be completely
gained or lost for atoms to become stable
 Covalent molecules: molecules in which
atoms share electrons
 Covalent bonds: bonds resulting from a
shared pair of electrons
 (co = with, valent = having power)

 Ex. formation of diatomic gases

 Molecules in which the electrons are shared
equally are called nonpolar covalently
bonded molecules

 When the electron pairs are not equally
shared, the result is a polar molecule
 (A molecule with two poles)

 Hydrogen bonds:
extremely weak bonds
formed when a Hydrogen
atom bound to one
electron-hungry atom is
attracted by another
electron-hungry atom
 (Nitrogen or Oxygen are
good examples of
electron-hungry atoms)
 Forms a “bridge”

 Hydrogen bonds are also important
intramolecular bonds
 They help binds different parts of the same
molecule together
 They are fragile but very important in
helping maintain the structure of protein
molecules

Synthesis reactions
Decomposition reactions
Exchange reactions

 Synthesis reactions: when two or more atoms
or molecules combine to form a larger, more
complex molecules

 Always involve bond formation
 Energy must be absorbed to make bonds
 Underlie all anabolic (constructive) activities
in body cells
 Important in growth and tissue repair

 Decomposition reactions: when a molecule is
broken down into smaller molecules, atoms
or ions

 Synthesis reactions in reverse
 Bonds are always broken
 Chemical energy is released
 Underlie all catabolic (destructive) processes
in body cells
 Molecule-degrading reactions
 Ex. food digestion and glycogen breakdown

 Exchange reactions: reactions that involve
both synthesis and decomposition reactions

 Bond are both made and broken
 A switch is made between molecule parts and
different molecules are formed

 Remember! Regardless of the type of
reaction, most chemical reactions are
reversible.
 Also temperature, particle size,
concentration of particles and catalyst
presence influence the rate of chemical
reactions

Basic Chemistry

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