UNIT II - BIOCHEMISTRY
Hillis ~ Ch 2,3
Dual Campbell ~ Ch 2,3,6
Big Campbell ~ Ch 2-5
Baby Campbell ~ Ch 2,3
I. THE MOLECULES OF LIFE
• Molecules are formed when two or more ______________ come together to
form covalent bonds.
 Created when electrons are ________________
 Single Covalent Bond
 Double Covalent Bond
 Triple Covalent Bond
 Very __________________
 Non-polar Covalent Bond

 Polar Covalent Bond

II. WATER
• Water
o Properties due to ________________
 Defined as
 Properties of Water
 Ability to form hydrogen “bonds”
 “Stickiness”
 Cohesion
 Surface Tension
 Adhesion
 Capillary Action
II. WATER, cont
 Regulation of Temperature
 High specific heat
 High heat of vaporization
 Density of “solid” water ____ density of liquid
water
 Solvent of Life

 “Water-loving”
 Polar molecules “pull apart” ionic
compounds & other polar molecules

 “Water-hating”
 Non-ionic and non-polar substances are
repelled by water
II. WATER, cont
 Dissociation of Water
 Rare, but measurable phenomenon

 In aqueous solution at 25˚C, [H+] + [OH-] = 1x10-14
 Neutral solution → [H+] = [OH-]
 [H+] =
 pH = Provides a means for a compressed
measurement of [H+]
 -log10[H+]
 Acid – Substance that dissolves in water to
____________ [H+]
 [H+] ____ 1 x 10-7; pH ____ 7
 Base - Substance that dissolves in water to
____________ [H+]
 [H+] ____ 1 x 10-7; pH ____ 7
 pH of Water =
II. WATER, cont
 Buffers
 Maintain a constant pH by donating, accepting H+
 Bicarbonate Buffer System
 Very important buffer system in blood
 pH of blood = _________
III. ORGANIC CHEMISTRY
• Carbon
o Atomic Number of C


 _____ valence electrons
o Hydrocarbons
o Isomer
III. ORGANIC CHEMISTRY, cont
Functional Group
Structure
Characteristics
Very polar; forms “ –ols”
Hydroxyl
Carbonyl
Carboxyl
Acts as an acid; donates H+
to solution
Amino
Acts as a base; removes H+
from solution
III. ORGANIC CHEMISTRY, cont
Functional Group
Structure
Characteristics
Sulfhydryl
Important in stabilizing protein
structure; forms disulfide
bridges
Phosphate
Gives molecule negative
charge; react with water to
release energy
Methyl
Affects the expression of
DNA
Functional Group ID
IV. THE BIOMOLECULES
• Most are ______________ made up of single units called ______________
• Four Main Groups




IV. BIOMOLECULES, cont
• Dehydration Synthesis
o
o
o
o
o
Also called ________________________
Reaction that occurs to build polymers
Forms ________________ bond between 2 monomers
____________lost as waste product
Requires energy input, enzymes
IV. BIOMOLECULES, cont
• Hydrolysis
o “________________________”
o Covalent bonds between monomers broken Releases energy;
reaction accelerated with enzymes
V. PROTEINS
• Important part of virtually all cell structures, processes, reactions
• Amino Acids – Proteins are large polymers made up of amino acid
monomers. All amino acids have the same basic structure:
 Amino group
 Carboxyl group
 Carbon known as alpha carbon
 R group → variable component; gives each amino acid its unique
properties. Determines whether amino acid is classified as polar, nonpolar, acidic, or basic.
V. PROTEINS, cont
V. PROTEINS, cont
V. PROTEINS, cont
V. PROTEINS, cont
• Amino Acid → Protein
o Dehydration synthesis results in formation of a peptide bond
o Polypeptide – many amino acids covalently bonded together
V. PROTEINS, cont
• Protein Conformation
o Protein’s shape is related to its function. Generally, a
protein must recognize/bind to another molecule to carry
out its function.
o Denaturation - A change in a protein’s shape. Results in a
loss of protein’s ability to carry out function.
o Four levels of protein structure
 Primary
 Secondary
 Tertiary
 Quaternary
V. PROTEINS
Protein Structure
 Primary
V. PROTEINS
Protein Structure, cont
 Secondary – Coiling of polypeptide chain due to formation of H-bonds
between H of amino end of one aa and OH of carboxyl end of another
aa
 Alpha helix – Created from H-bonds forming within one pp chain
 Beta pleated sheet – H-bonds form between aa in parallel pp chains
V. PROTEINS
 Tertiary
Protein Structure, cont
 Involves
interactions
between R
groups of amino
acids.
 Helps to give
each protein its
unique shape.
V. PROTEINS
Protein Structure, cont
 Quaternary
 Proteins that are
formed from
interactions
between 2 or more
polypeptide chains
folded together
 Examples include
hemoglobin,
collagen, chlorophyll
V. PROTEINS
Protein Structure, cont
V. PROTEINS
Protein Structure, cont
V. PROTEINS
Protein Function
V. PROTEINS
Protein Function, cont
V. PROTEINS
Protein Function, cont
• Cell Communication
V. PROTEINS
Protein Function, cont
• Enzymes
o Biological catalysts
that act by
lowering
activation energy;
that is, the
amount of energy
needed to get the
reaction going
o Only catalyze
reactions that
would normally
occur
V. PROTEINS
Enzymes
V. PROTEINS
Enzymes, cont
o
o
o
o
Recycled – not used up or changed by the reaction
Temperature and pH sensitive
Substrate specific
May require a co-factor or co-enzyme to be functional
V. PROTEINS
Enzymes, cont
o Induced Fit
 As enzyme envelops substrate, a
slight change takes place in bond
angles, orientation of atoms.
 Allows chemical rxns to occur
more readily
o Inhibition of Enzyme Function
 Competitive inhibitor – mimics
normal substrate
 Non-competitive inhibitor –
attaches to another part of
enzyme; changes shape of active
site
V. PROTEINS
Enzymes, cont
o Regulation of Enzyme Function
 Allosteric Regulation
Binding of a molecule to enzyme that affects function of
protein at another site
May act as activators or inhibitors
V. PROTEINS
Enzymes, cont
o Regulation, cont
 Feedback
Inhibition
As end product
is synthesized
and
accumulates,
enzyme is
inactivated →
switches off
metabolic
pathway
VI. CARBOHYDRATES
•
•
•
•
Provide fuel, act as building material
Generally, formula is a multiple of
Contain
Monomer = monosaccharides
• Monosaccharides – usually found as ringed structures
o Pentoses
 Ribose
 Deoxyribose
VI. CARBOHYDRATES, cont
o Hexoses
 Glucose
 Fructose
 Galactose
VI. CARBOHYDRATES, cont
• Disaccharides
o Formed by
o Example
Sucrose
Lactose
Maltose
VI. CARBOHYDRATES, cont
• Polysaccharides
o Many monosaccharides covalently bonded together through
dehydration synthesis
o Two main groups
 Energy Storage Polysaccharides
Starch
Plants store glucose as starch in cell structures called
plastids.
Humans have enzymes to hydrolyze starch to glucose
monomers.
Glycogen
Storage form of glucose in animals.
More highly-branched than starch.
In humans, found mainly in liver, muscle cells
VI. CARBOHYDRATES, cont
 Structural polysaccharides
 Cellulose
 Polymer of glucose.

 Chitin
 Found in arthropod exoskeleton, cell walls of ____________
VII. LIPIDS
•
•
•
•
•
Very diverse group
Not true polymers
Four groups




VII. LIPIDS, cont
• Fats& Oils
o Composed of glycerol +
3 fatty acids
o Glycerol = 3-C alcohol
o Fatty acids – long
hydrocarbon chains
ending with carboxyl
group
o AKA triglycerides
o Used for energy storage
VII. LIPIDS, cont
 Saturated Fats





Contain all single bonds
“Saturated with hydrogens”
Typically from animal source
Solid at room temp.
Associated with greater
health risk.
 Unsaturated Fats
 Contain double bonds
 Fewer H-atoms
 Produces “kinked”
hydrocarbon chain
 Typically from plant source,
liquid at room temp.
VII. LIPIDS, cont
• Phospholipids
 2 fatty acids, each attached
to carboxyl group of
glycerol.
 Negatively-charged
phosphate group is
attached to 3rd carboxyl
 Partially polar and partially
non-polar
 Found in all cell
membranes.
VII. LIPIDS, cont
• Steroids
 Consist of 4-rings with different functional groups attached
 Cholesterol
 Found in animal cell membranes
 Precursor for sex hormones
VII. LIPIDS, cont
• Waxes
 Very hydrophobic
 Used as coating, lubricant
VIII. NUCLEIC ACIDS
• Nucleic acid group includes DNA,
RNA, ATP
• Monomers = __________________
 Composed of
 Pentose


 Phosphate group
 Nitrogen base
• Polymers formed through
____________________________
 Phosphate group of one
nucleotide covalently binds to
sugar of next
VIII. NUCLEIC ACIDS, cont
 Nitrogen Bases
Pyrimidines



Purines


VIII. NUCLEIC ACIDS, cont