Chapter 3
Biological Molecules
3.1. Why Is Carbon So Important in
Biological Molecules?
• All contain carbon
– Organic refers to molecules containing a
_______ skeleton
– Inorganic refers to ___________ and all
molecules without ___________
3.1. Why Is Carbon So Important in
Biological Molecules?
• Each carbon can form up to ______ bonds
(single(2 electrons), double, or triple) and
rings
• Carbon makes bonds mostly with ________
________________ in living systems
• Biomolecules are large and contain _______
_____________ attached to the carbon
backbone.
• Functional groups in organic molecules
confer _____________________________ _
3.2. Organic Molecule Synthesis
• Biomolecules are ___________ (chains) of
subunits called _____
• Monomers are joined together through
__________________________
– An H and an OH are removed, resulting in the loss
of a water molecule (H2O)
3.2. Organic Molecule Synthesis
• Polymers are broken apart through
______________ (“water cutting”)
– Water is broken into H and OH and used to
break the bond between monomers
3.2. Organic Molecule Synthesis
• All biological molecules fall into one of four
categories
What Are Carbohydrates?
•
Composition
•
Types
– Simple or single sugars are
________________
– Two linked monosaccharides are
____________________
– Long chains of monosaccharides are
_________________
What Are Carbohydrates?
•
Function:
•
Most are water- soluble due to the _____
______ functional groups
Monosaccharides
•
Basic Structure
– Backbone of 3-7 _________ atoms
– Many –OH and –H functional groups
– Usually found in a ring form in cells
•
Examples:
–
–
–
–
__________ (C6H12O6): the most common
_________ (found in corn syrup and fruits)
__________ (found in lactose)
______ and ____________(found in RNA and
DNA)
Monosaccharides
Monosaccharides
• Fate inside a cell
– Some broken down to free their chemical
______________
– Some are linked together by ___________
synthesis
Disaccharides
• Disaccharides are two-part sugars
– ________ (table sugar) = glucose + fructose
– _______ (milk sugar) = glucose + galactose
– _________ (malt sugar)= glucose + glucose
Polysaccharides
• Monosaccharides are linked together to form
chains (__________________)
• Storage polysaccharides:
– Polymers of Glucose:
• _____________. Formed in roots and seeds
• __________________. Found in liver and muscles
Polysaccharides
• Structural polysaccharides
– ___________ (polymer of glucose).Found in the
cell walls of plants
• Indigestible for most animals due to orientation of
bonds between glucoses
Polysaccharides
• …Structural polysaccharides continued
– ______ (polymer of modified glucose units)
• Found in the outer coverings of insects, crabs, and
spiders
• Found in the cell walls of many fungi
3.4. What Are Lipids?
• _________________________
• Function
• Contain Only ___
• Most are hydrophobic and water insoluble, due
to long ___
• Types:
• Main subunit:
Oils, Fats, and Waxes
• Made of one or
more
• Formed by
synthesis
– 3 _________ +
_____________ 
_______________
(95% of all lipids in
the body)
Oils, Fats, and Waxes
• Fats and oils used
for _____________
energy storage
– __________ of
stored chemical
energy
Oils, Fats, and Waxes
• Fat solidity is due to
_________________
carbon bonds
– Fats that are solid at
room temperature are
__________________
(carbon chain has as
many hydrogen atoms
as possible, and
mostly or all C-C
bonds), e.g. beef fat
Oils, Fats, and Waxes
• Fats that are liquid at
room temperature are
______________
(fewer hydrogen
atoms, many C=C
bonds), e.g. corn oil
• Unsaturated trans fats
have been linked to
heart disease
Oils, Fats, and Waxes
• Waxes are composed of ______________
________________ and are strongly
hydrophobic
• Waxes are highly saturated and___
Oils, Fats, and Waxes
• Waxes form __________
coatings
– _______________ of
plants
– ________ in mammals
– Insect _______________
• Used to build _________
structures
Phospholipids
• Phospholipids: form ________________
around all cells
• Construction
Phospholipids
• Phospholipids have
– Polar functional groups are water _______
– Nonpolar fatty acid “tails” are water _________
Steroids
• Steroids are composed of
•
• Examples of steroids
–_
• Found in membranes of
animal cells
–_
3.5. What Are Proteins?
• Proteins are formed from chains of ______
______ (monomers; _____ different)
• The _______________________ of amino
acids in a protein dictates its function
Amino Acids
•
All amino acids have similar structure
– All contain _____________________ groups
– All have a variable ______ group
•
•
•
Some R groups are hydrophobic
Some are hydrophilic
Cysteine R groups can form _________________
Amino Acids Diversity (20)
Protein Synthesis
• Amino acids are joined to form chains by
_________________ synthesis
– An ________ group reacts with a ________
group, and water is lost
Dehydration Synthesis
• Resultant covalent bond is a ____________
• Long chains of amino acids are known as
________________ or just _____________
Four Levels of Structure
• Proteins exhibit up to four levels of structure
– Primary structure
– Secondary structures
– Tertiary structure refers to complex _____ of
the protein chain held together by
– Quaternary structure is found where
R
R
O
C
N C
H
R
C C
N
N C
C
N C
C
O
R
H
N
C
C C
N
N C C
N C
C
O
H
R
O
N C
O
N
C C
N C C
O
R
R
C
R
O
O
R
O
C
R
O
R
O
R
Pleated sheet
R
O
C
N C
N C
C
O
H
R
C
C
N C
O
polypeptide
R
R
O
R
C C
N
N C C
C
O
R
hydrogen
bond
s
s
s-s
s-s
s
s
s-s
keratin
s
s
Three Dimensional Structures
– Precise positioning of amino acid R groups
leads to bonds that determine
– Disruption of these bonds leads to _________
proteins and
3.6 What Are Nucleic Acids?
• ____________ are the
monomers of nucleic
acid chains
• Each nucleotide has
three parts:
Molecules of Heredity
• A ____________ bond forms between
nucleotides to make a chain:
• Two types of nucleotides
– Ribonucleotides _____________ found in RNA
– Deoxyribonucleotides ____________ found in
DNA
Molecules of Heredity
• Two types of polymers of
nucleic acids
– ___________________
found in chromosomes
• Carries ______________
needed for protein construction
– _____________________
• ____________ used directly in
protein construction
Molecules of Heredity
• Each DNA molecule
consists of
Functions of Nucleic Acids
• DNA and RNA, the Molecules of Heredity, Are Nucleic
Acids
• Other Nucleotides Act as :
• _
carry chemical signals between molecule
–– Adenosine triphosphate ______ carries energy stored in
bonds between phosphate groups
– __________________________ carry electrons
–– -_______________ help enzymes promote and guide
chemical reactions
Vitamin
NH2
N C
C
NH2
N C C
N
N
HC
HC
N C N CH
O
CH2
H H
O
P
O
OH
O
HO
H
P
O
H
OH
O
P
O
P
O
HO
N C N CH
OH
O
O
O
CH2
H H
N C C N
P O
HC
O
H
H
OH
OH
NH2
O
HO
O
P O
OH
CH2
H H
OH
OH
Cyclic adenosine
monophosphate (cyclic AMP)
(intracellular communication)
Adenosine triphosphate (ATP)
(energy carrier)
A sampling of the diversity of nucleotides
N C N CH
O
H
H
OH
Coenzyme
(active in cellular
metabolism)