C HAPTER 3 Biochemistry
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S ECTION 1 P RETEST Organic Compound Functional Group Monomer
Polymer Macromolecule Condensation Reaction Hydrolysis ATP A.A
simple molecule that combines with other molecules to make a larger
molecule B.The main energy molecule for organic processes.
C.Reaction when two molecules combine to produce water. D.The
portion of a molecule that is active in a chemical reaction
E.Carbon containing compound F.A large molecule formed when smaller
units combine G.Chemical reaction involving water and another
substance to produce something new H.Very large molecules formed
from hundreds or thousands of atoms
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A NSWER KEY Organic Compound E Functional GroupD MonomerA
PolymerF MacromoleculeH Condensation ReactionC HydrolysisG
ATPB
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T HE E LEMENT OF L IFE : CARBON Carbon is regarded as the
element of life Organic Compounds contain carbon (and hydrogen)
Carbon can form the large, complex molecules common to all living
things because of its structure. Carbon has 4 electrons in its
outer shell. The shell can hold 8. Carbon needs 4 more electrons to
become stable, creating up to four covalent bonds.
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Carbon also has a tendency to bond with itself. This can result
in big biological molecules based around chains or rings of carbon
atoms.
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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 Each line represents a covalent bond.
Carbon must have four covalent bondsor four lines
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F UNCTIONAL G ROUPS Functional group the portion of a molecule
that is active in a chemical reaction and that determines the
properties of many organic compounds. Example Hydroxyl OH Makes
molecules polar, this means they are hydrophilic (soluble in water)
Called alcohols
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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 2-
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L ARGE C ARBON M OLECULES 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 )
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C ONDENSATION R EACTIONS 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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H YDROLYSIS Polymers break down by a hydrolysis reaction In
these reactions; water is used
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T HE E NERGY M OLECULE : ATP Adenosine triphosphate (ATP) a
molecule that stores a large amount of energy in its overall
structure. This is a major source of energy for most living cells
Named the energy currency for living cells because it is nearly a
universal molecule of energy transfer in living things Energy can
be stored as carbohydrates or lipids, but that energy (in chemical
bonds) must be transferred to ATP before it can be used in the
cell
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S TRUCTURE OF ATP ATP is made of Adenine and Ribose and three
phosphate groups Adenine = nitrogen containing compound Ribose =
5-carbon sugar Phosphate groups = PO 4 -
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The Hydrolysis of ATP is used by the cell to provide the energy
needed to drive chemical reactions. It happens according to the
following diagram: 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
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S ECTION 2 P RETEST Carbohydrate Monosaccharide Disaccharide
Polysaccharide Protein Amino acid Peptide bond Enzyme Substrate
A.Organic compound made of amino acids B.Organic compound made of
carbon, hydrogen and oxygen C.Proteins that speed up chemical
reactions. D.Simple sugar E.Double sugar F.Buiding blocks of
proteins G.Holds amino acids together when forming proteins H.Sugar
formed from three or more monosaccharides I. The reactant in a
chemical equation that is acted upon by enzymes
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Active site Lipid Fatty acid Phospholipid Wax Steroid Nucleic
Acid DNA RNA Nucleotide J.Unbranched carbon chains that make up
lipids K.Type of lipid forming protective layers on plants and
animals L.Type of lipid found in many hormones M.Deoxyribonucleic
acid N.Folds found in enzymes that fit into a specific substrate
O.Ribonucleic acid P.Large organic compounds that do not dissolve
in water Q.Type of lipid found in the cell membranes of living
things. R.Large organic compounds that store and transfer
information in cells S. Part of a DNA molecule
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A NSWER K EY Carbohydrate B MonosaccharideD DisaccharideE
PolysaccharideH ProteinA Amino acidF Peptide bondG EnzymeC
SubstrateI Active siteN LipidP Fatty acidJ PhospholipidQ WaxK
SteroidL Nucleic AcidR DNAM RNAO NucleotideS
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T HE M OLECULES OF L IFE Four main groups of organic compounds:
Carbohydrates Proteins Lipids Nucleic Acid
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C ARBOHYDRATES Composed of carbon, hydrogen and oxygen Make up
about 1% of a cell Used for energy and structural materials Three
types: Monosaccharides simple sugar Disaccharides double sugar
Polysaccharides three or more monosaccharides
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Monosaccharides Contain C,H and O in a ratio of 1:2:1 (CH 2 O)
n Note: N = whole # from 3-8 Examples Glucose (energy for cells)
Fructose (fruit sugar) Galactose (milk sugar) Note: All three have
the same molecular formula C 6 H 12 O 6 just different structures
therefore they are called isomers
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Disaccharides two monosaccharides combine in a condensation
reaction. Example: Sucrose (table sugar) Formed when glucose and
fructose combine Sucrose
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Example: Glucose and Fructose combine to form Sucrose
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Polysaccharide three or more monosaccharides form a much more
complex molecule. Examples: Glycogen hundreds of glucose molecules
joined in a large branching chain. Stored in the liver and muscles
of most animals and is used for quick energy Starch glucose
molecules joined together and stored in plants for energy.
Cellulose thousands of glucose molecules joined together in a
straight chain. Provides the structure for plant cell walls
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P ROTEINS Composed of C, H, O and N Make up about 15% of a cell
Found in hair, horns, skin, muscles, and enzymes Chains of amino
acids (building blocks of proteins) 20 different amino acids with
similar structures Only their R group varies The R groups determine
their different shapes and functions Carboxyl Group
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Dipeptide two amino acids joined by a peptide bond. Peptide
bonds are formed by condensation reactions in which water is
released Polypeptide long chains of amino acids. They fold and bend
themselves into large protein molecules. Temperature and solvent
type can influence the shape of proteins. Ex: egg whites
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Enzymes special types of proteins that act as catalysts The
enzyme can attach only to a substrate (reactant) with a specific
shape. The enzyme changes and reduces the activation energy of the
reaction so reactants can become products. The enzyme is unchanged
and is available to be used again.
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L IPIDS Composed of C, H and O but in a higher ratio of carbon
and hydrogen atoms to oxygen atoms than carbohydrates have:
therefore, they store more energy Make up about 10% of a cell Used
to store extra energy and in cell membranes Nonpolar do not
dissolve in water Most are made of fatty acids bonded to other
molecules Examples: triglycerides, phospholipids, steroids, waxes,
and pigments
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F ATTY A CIDS To fully understand how lipids work, we need to
first understand their fatty acid component Fatty acids long,
unbranched carbon chains with a carboxyl group on one end. Carboxyl
end = polar and reacts with water (hydrophilic water loving)
Hydro-carbon end = nonpolar and does not react with water (
hydrophobic water fearing)
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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)
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C LASSES OF L IPIDS 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
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N UCLEIC A CIDS Composed of C, H, O, N, and P Make up 4% of a
cell Consists of repeating monomers called nucleotides Each
nucleotide has a phosphate group, a 5-carbon sugar and a nitrogen
base Important in the transfer of information in the cell Types:
DNA Deoxyribonucleic acid : determines the characteristics of an
organism and directs cell activities RNA Ribonucleic acid :
transfers information from DNA to ribosomes: helps manufacture
proteins: can act as enzymes