Chemistry Comes Alive

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Chemistry Comes Alive
Chemistry Again??
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I. Matter and Energy   A. Matter - anything
that has mass and occupies space   1. Matter
exists in one of three states in the
body. solids - definite shape and
volume Ex. bones and teeth   liquids -
definite volume, no definite shape Ex. blood
plasma. lymph   gases - no definite shape or
volume Ex. air in lungs
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2. Matter can be changed chemically or
physically   physical change - change in
properties but no change in identity. Ex.
phase change, chewing food into smaller
pieces   chemical change - change in the
identity of a substance Ex. digestion of
food
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B. Energy - ability to do work   1. kinetic
energy - energy of motion. Present when energy
is doing work by moving some object.   2.
potential energy - energy that is stored and has
the potential to do work   3. Forms of
energy   chemical energy - energy stored in the
bonds of chemical substances Ex. energy
stored in food
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chemical energy - energy stored in the bonds of
chemical substances Ex. energy stored in
food   electrical energy - energy that results
from moving electrical charges Ex. nerve
impulses   mechanical energy - energy directly
involved in moving matter Ex. muscle
contractions   radient energy - energy that
travels in electromagnetic waves Ex. light
energy that stimulates the rods and cones in
our retina
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4. Enegry conversions - the conversion of energy
from one form into another form with some
loss.   During energy conversions energy is lost
as heat.
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II. Basic Chemistry   A. Atomic
Structure   1. nucleus contains protons and
neutrons a. protons positive
charge mass number 1 b.
neutrons neutral charge mass number
1 provides strong nuclear force that
holds the nucleus together c. atomic
number - the number of protons d. atomic
mass - the number of protons and neutrons
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2. The Electron Cloud a. electrons
- negative charge mass 1/ 1856 of a
proton b. electrons exist in differing energy
levels - greater energy further from the
nucleus c. electrons exist in pairs contained
in differing orbitals d. valence electrons
- the electrons in the outermost energy level
that are involved in chemical bonding
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B. Chemical Bonding   1. Atoms bond to
achieve a full outer energy level (valence
shell). 2. Atoms can gain, lose, or share
electrons   3. Ionic bond atoms transfer
electrons one atom gains and one atom
loses
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4. Covalent bond atoms share
electrons nonpolar covalent - electrons shared
equally polar covalent - electrons spend
more time around one atom than the other
atom 5. Electronegativity tendency of an
atom to attract electrons in polar covalent
bonding one atom is more electronegative than
the other atom
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6. Hydrogen Bonding weak interaction between
a polar covalently bonded hydrogen atom
in one compound and an electronegative atom
in another compound Examples of hydrogen
bonding 1. produces the helical structure of
protein molecules ( the secondary
structure) 2. produces the 3 dimensional
structure of proteins ( the tertiary
structure) 3. connects the two nucleic acid
strands together in a molecule of DNA
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II. Chemical Reactions   A. Reactants and
Products   1. Reactants - enter into a
chemical reaction
2. Products - produced by a chemical reaction
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B. Types of Chemical Reactions   1.
synthesis reaction - small molecules are
assembled into larger molecules 2.
decomposition reaction - large molecule is
broken apart into small pieces 3. single
replacement reaction - an uncombined atom
replaces an atom in a compound 4. double
replacement reaction - two compounds exchange
parts  
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5. dehydration synthesis used by the body to
build large molecules - starch, protein, lipids,
nucleic acids two small molecules are joined as
a molecule of water is released - general
formula R-OH R1-OH R-O-R1
H2O   6. hydrolysis used by the body to
split large molecules apart a large molecule is
split by the addition of water Ex. digestion
of food splitting of ATP into ADP general
formula   R-O-R1 H2O R-OH
R1-OH
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C. Chemical Reactions and Energy   1.
Endothermic energy - absorbs energy   2.
Exothermic reaction - releases energy   3.
Activation energy - the energy needed to start
a chemical reaction catalysts - speed up a
reaction by lowering its reaction
energy enzymes - protein catalysts
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  4. Cells use ATP to provide the energy needed
for biochemical reactions ATP Adenosine
triphosphate energy is contained in the
phosphate bonds general formula   ATP
Adenosine-PO4-PO4-PO4 ADP
Adenosine-PO4-PO4 The energy reaction is
the following
ADP energy ATP   ATP
ADP energy
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D. Reaction Rates   The rate of a chemical
reaction is determined by the following
factors 1. the reactants 2. the
concentration of the reactants 3. the
temperature 4. the presence of
catalysts/enzymes   E. Some chemical reactions
are reversible depending on the conditions
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III. Acids and Bases   A. Acids are compounds
that donate hydrogen atoms and form H3O ions
when in an aqueous solution.   B. Bases are
compounds that accept hydrogen atoms and form OH-
ions when in an aqueous solution. C. pH is a
measure of the acidity or alkalinity of a
solution pH -log H3O human blood and
body fluids have a pH of about 7.06 (slightly
acidic)   D. Acids and bases react to produce a
salt and water. The reaction is called
neutralization   E. A buffer is a compound that
resists changes in pH.
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IV. Water A. universal solvent 1. dissolves
most types of compounds 2. forms hydrogen bonds
between the molecules 3. polar covalent bonding
between hydrogen and oxygen 4. good solvent
for the chemicals needed by living
organisms B. has a high specific heat -
absorbs a large amount of heat energy before a
change in temperature   C. Many compounds (Ex.
salts and ionically bonded compounds) separate
into different parts when they dissolve. The
process is called dissociation.
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V. Biological molecules  A. All life on earth
is based on carbon. Carbon atoms provide the
backbone on which all biological molecules are
built.   1. Carbon atoms form four covalent
bonds with other atoms. 2. Carbon atoms can
form compounds that are shaped like long chains,
branched chains, or ring structures. 3. Carbon
can form single, double, or triple bonds 4.
Carbon atoms can form bonds with many other
elements
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B. Carbohydrates 1. Have the same proportion
of hydrogen and oxygen atoms as water 2. Can
exist in different forms monosaccharides Ex.
glucose, fructose disaccharides Ex.
sucrose, lactose polysaccharides Ex. starch,
cellulose
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3. Used by living things as an energy source
and for structural stability glucose - the
main molecule used for energy by all
organisms starch - used by plants to store
energy. Consists of many glucose molecules
bonded together glycogen - used by animals to
store energy. Consists of many glucose
molecules bonded together cellulose -
contained in plant cell walls. gives
structural support chitin - used in the
exoskeleton of arthropods
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3. Starch versus cellulose both composed of
glucose molecules the difference is in the
connections animals have the enzymes needed to
break apart starch molecules but do not
have the enzymes needed to break apart
cellulose
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C. Lipids

• Contain carbon, hydrogen, and oxygen
• Ratio of C to O is greater than 21
• Contain more energy than carbohydrates or
  proteins (9 kCal per gram)
• Insoluble in water dissolve in organic solvents
• 3 most common forms in the body neutral fats,
  phospholipids, steroids
• Found in marbled meats, egg yolks, milk products,
  oils

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D. Neutral Fats

• Composed of fatty acids and glycerol
• Molecule resembles an elongated E
• May be solid as in animal fat molecule is
  saturated (contains no double bonds between
  carbon atoms)
• May be unsaturated as in plant oils contain
  carbon to carbon double bonds

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Neutral Fats cont.

• Represent the bodys most abundant and
  concentrated source of energy
• Present in fatty deposits under the skin and
  around body organs
• Fats also help insulate the body from heat loss
  and cushion tissues from bumps

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E. Phospholipids

• Similar to neutral fats except a phosphate
  containing group replaces one fatty acid chain
• The phosphate group is charged and gives the
  molecule different chemical properties
• Phospholipids in cell membranes allow for
  selective permeability

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F. Steroids

• Complex molecules formed of 4 interlocking rings
• Cholesterol is the most important steroid found
  in all cell membranes, forms a portion of the
  myelin sheath around nerves, forms vitamin D,
  some hormones, and bile salts
• Found in foods such as eggs, cheese, and meat
• Implicated in the pathogenesis of
  arteriosclerosis

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G. Lipids - fats, oils, and waxes   1.
contain more energy than carbohydrates 2.
composed of a glycerol backbone and three fatty
acid chains a fatty acid is a long chain
organic molecule, one end has a carboxyl
group (organic acid)   3. phospholipids
contain a phosphate group substituted for a
fatty acid   4. Waxes contain long chain
alcohols substituted for one fatty acid
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5. Functions of lipids lipids play a role
in energy storage for the organism and are a
main component of cell membranes phospholipi
ds are a component of cell membranes and the
myelin sheath around neurons some lipids
dissolve certain vitamins
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G. Proteins

• Compose over 50 of the organic matter in the
  body
• Some play a role in the structure of body and
  cell components
• Some play a role in body metabolism
• Contain the elements C, H, O, N, S

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Proteins cont.

• Composed of small molecules called amino acids.
• 20 amino acids needed for life
• All contain an amine group (gives them bacis
  properties) and an acid group (gives them acidic
  properties)
• All are identical except for a side chain called
  the R-group
• A chain of fewer than 50 amino acids is called a
  polypeptide a longer chain is called a protein

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H. Proteins - the main structural component of
cells.   1. composed of long chains of amino
acids their structure is described in the
following way the primary structure is the
sequence of amino acids the secondary
structure is the helical coiling of the
chain the tertiary structure is the degree of
folding and coiling of the chain into a rigid 3
dimensional shape the quaternary structure is
the association of multiple amino acid
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Proteins cont.

• Based on structure proteins are classed as
  globular or fibrous
• Globular mobile, spherical molecules that play
  a role in biological processes also called
  functional proteins. Ex. Enzymes, blood proteins,
  hemoglobin, immunoglobulin, hormones
• Fibrous make up body structures, provide
  strength, also called structural proteins Ex.
  Collagen, keratin

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I. Enzymes

• Catalyze metabolic reactions
• Bind to reactants and cause the reaction to
  proceed with greater speed
• Are VERY specific a particular enzyme will only
  bind to a particular chemical
• Lock and Key model

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chains into one active protein molecule   2.
enzymes are protein catalysts produced by
cells to speed up biochemical reactions lock
and key model - the 3 - D shape of an enzyme
acts like a key as it fits into the active site
on another molecule
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J. Nucleic Acids

• Play key role in reproduction (cellular and
  organism) and in protein synthesis
• Building block are nucleotides
• DNA carries genetic information, compose genes,
  double helix, composed of complementary bases
  A,T,G,C
• RNA single strand key role in protein
  synthesis, 3 types mRNA. rRNA, tRNA, composed
  of the bases A, U, G, C

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K. Nucleic acids - DNA and RNA   1.
DNA double helix carries genetic
information composed of nucleotides nucleoti
de chains connected by hydrogen bonds
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2. RNA single chain directs the production
of proteins 3 types - messenger RNA -
carries genetic information from the nucleus
to the cytoplasm transfer RNA - carries amino
acids to the site of protein synthesis ribosom
al RNA - component of ribosomes that carry out
protein synthesis
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L. Adenosine Triphosphate

• Main method by which cells store energy
• ADP energy ATP
• ATP ADP energy