Chemistry is important to biologists because all of the life
activities in our cells that keep us alive are the result of
chemical reactions. Matteranything that has mass and takes up
space. Elementsfound on Periodic Table. Cannot be broken down into
simpler kinds of matter. HONC (Honk)hydrogen, oxygen, nitrogen,
carbon. These are the most important elements in living
things.
Slide 3
Atomsimplest particle of an element that keeps all the
properties of that element. Parts of an atom Protonspositive charge
Neutronsno charge Electronsnegative charge Inside Nucleus Orbit
Nucleus
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The atomic number is the number of protons in an atom The
atomic mass is the number of protons plus the number of neutrons.
The number of electrons in an atom is the same as the number or
protons giving it a net charge of zero.
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Isotopesatoms of the same element with different number of
neutrons.
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Compounds atoms of two or more elements joined by chemical
bonds. Examples: H 2 O NaCl C 6 H 12 O 6 Three models below show a
water molecule http://www.lionden.com/graphics/AP/ Water1.gif Stick
model Bohr model Electron Cloud model
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Chemical bonds are attractive forces that hold atoms together.
They form so that elements can become more stable by filling their
outer energy levels.
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Covalent Bondstwo atoms SHARE electrons
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Carbon has the ability to form multiple covalent bonds Carbon
has 4 electrons in its outer shell. The shell can hold 8. Carbon
needs 4 more electrons to become stable. This can result in big
biological molecules based around chains of carbon atoms.
http://www.chemistrydaily.com/chemistry/upload/d/d9/ Covalent.png
http://t1.gstatic.com/images?q=tbn:ANd9GcTDsTGWMhdl6_3izM7K7RCw6b5ueLWXpac
Sg91FXY8Tt6PoObw&t=1&usg=__fkitOKpfQ768Lo6SF7eDzZ0qobs=
Slide 10
Many complex biological molecules will be formed using double
and triple covalent bonds. Double share 2 pair of electrons Triple
share 3 pair of electrons Ethane Ethylene Acetylene
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Ionic Bondsatoms LOSE or GAIN electrons creating charges that
attract each other. SALTS!!!!
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Chemical reactions occur when one or more substances change to
produce one or more new substances. Chemical equations show what
happens during the reaction Reactants on left Products on right 6CO
2 + 6 H 2 O C 6 H 12 O 6 + 6O 2 +energy
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Most reactions need the addition of energy before they will
begin. Activation Energy energy required for a reaction to begin
Catalyst speed up chemical reactions by lowering the activation
energy required. Enzymes are common catalysts in living things They
remain unchanged throughout the reaction.
http://xnet.rrc.mb.ca/davidb/photogallery/activatione
nergy1.gif
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Endothermic reactions result in a net absorption of energy
Exothermic reactions results in the net release of energy
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Also called Redox Reactions Electrons are transferred between
atoms Oxidation reaction a reactant loses electrons resulting in a
positive charge ExampleNa loses an electron to become more stable
creating a sodium ion (Na + ) Reduction reaction a reactant gains
electrons resulting in a negative charge ExampleChlorine gains an
electron to become more stable creating a chlorine ion (Cl - ) The
two always occur together. One reactant gives up what the other
needs.
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Waters chemical structure is important in its vital role in
life. http://www.lenntech.com/images/Water%20mo lecule.jpg
http://www.ci.rockford.il.us/uploadedImages/government/PublicWorks/Water/willing%20water
%20color.jpg
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Water is POLAR Electrons in the covalent bond are not shared
equally. Results in a partial negative charge on the oxygen end and
a partial positive charge on the hydrogen end.
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Being polar allows water to: Dissolve many substances Form
hydrogen bonds with other water molecules creating: Cohesion
Surface Tension Adhesion Capillarity High heat capacity Less
density when water freezes (ice floats!!)
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Solution mixture in which one or more substances are uniformly
distributed in another substance. Solute dissolved substance
Solvent substance in which the solute is dissolved Concentration
amount of solute dissolved in a fixed amount of solution Saturated
Solution no more solute can be dissolved
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Water molecules can collide and break each other apart H 2 O H
+ + OH - OH - is known as the hydroxide ion Free H+ ions react with
water molecules: H + + H 2 O H 3 O + H 3 O + is known as the
hydronium ion
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Acid solution in which the number of hydronium ions is greater
than the number of hydroxide ions They have a value BELOW 7 on the
pH scale. Base solution in which the number of hydroxide ions is
greater than the number of hydronium ions (Alkaline) They have a
value ABOVE 7 on the pH scale
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Carbonelement of life Organic compoundscontain carbon (and
hydrogen) Can form 4 covalent bonds with other elements so it is
the backbone of all organic compounds.
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Various functional groups can be attached to these carbon
backbones. These groups determine how these molecules will react
with other molecules. Functional groups can be seen on the
following chart:
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Hydroxyl (Alcohols) Functional Group Structural FormulaExample
-OH Carbonyl (on end) (Aldehydes) - C=O H Carbonyl (in middle)
(Ketone) C O Carboxyl (Organic Acids) COOH Amino (Amino Acids) NH 2
Phosphate (Nucleic Acids) PO 4 3-
Slide 25
The building of large molecules occurs as follows: Monomers
small, simple carbon molecules Polymers consists of repeated,
linked monomers Macromolecules large polymers: (Carbohydrates,
lipids, proteins, nucleic acids)
http://kenpitts.net/bio/human_anat/monome r.jpg
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Polymers form during condensation reactions In these reactions;
water is released
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Example: Glucose and Fructose combine to form Sucrose
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Polymers break down by a hydrolysis reaction In these
reactions; water is used
http://imcurious.wikispaces.com/file/view/hydrolysis_reaction.jpg/113609729/hydrolysis_reacti
on.jpg
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Adenosine Triphosphate (ATP ) the most important energy
currency molecule of cells. Made of Adenine; Ribose (a sugar) and 3
phosphate groups
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The Hydrolysis of ATP is used by the cell to provide the energy
needed to drive chemical reactions.
http://kentsimmons.uwinnipeg.ca/cm1504/atp.htm -ATP can lose its
end phosphate which releases the energy stored in it. and makes
adenosine diphosphate (ADP). -This energy is used to do work in the
cell. -Adding the phosphate back to make ATP requires that we add
energy
Slide 31
Four main groups of organic compounds: Carbohydrates Proteins
Lipids Nucleic Acids
http://ez002.k12.sd.us/Chapter%20One%20Science.htm
Slide 32
Used for energy Three types: Monosaccharides (glucose and
fructose) Disaccharides (sucrose) Polysaccharides (glycogen, starch
and cellulose) Structure is too complex to show
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Made of chains of amino acids held together by peptide bonds.
Dipeptides (two amino acids) Polypeptides (long chains of amino
acids) that fold and bend into proteins. Typical amino acid
Slide 34
Form by condensation reactions.
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Enzymes special types of proteins that act as catalysts
Slide 36
Lipids are fats. Used for energy Nonpolar Fatty acids bonded to
other molecules
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Saturated Fatty Acids each carbon is covalently bonded to four
atoms (NO DOUBLE BONDS) Unsaturated Fatty Acids not all carbons are
bonded to four other atoms (HAS DOUBLE BONDS)
http://www.biology.lsu.edu/introbio/Link2/fatty%20acids.gif
Slide 38
Triglycerides (fats) three molecules of fatty acid joined to
one molecule of glycerol. Saturated triglycerides the 3 fatty acids
are saturated: hard at room temp: found in butter and red meat: bad
fats Unsaturated triglycerides the 3 fatty acids are unsaturated:
soft at room temp: found in plant seeds: good fats Phospholipids
two fatty acids joined to glycerol. They also have a phosphate
group. Important part of all cell membranes Waxes fatty acid chain
joined to an alcohol chain: waterproof: form protective layers in
plants and animals Steroids four fused carbon rings with a
functional group: include many hormones and cholesterol
Slide 39
Include DNA and RNA Information molecules Made of repeating
monomers called nucleotides. Phosphate, pentose sugar, nitrogenous
base.
