Biological Macromolecules
Chapter 3
Lecture Objectives:
1. Understand the difference between monomers
& polymers
2. Understand the 4 classes of Macromolecules
(Carbs, Lipids, Proteins, Nucleic Acids)
Yummy – pizza!
LARGE BIOLOGICAL MOLECULES
 There are four categories of large biological molecules:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
* Carbon serves as the backbone for most of these
molecules
© 2013 Pearson Education, Inc.
Carbon is very diverse……….
Double bond
Carbon skeletons vary in length
Carbon skeletons may be unbranched
or branched
Carbon skeletons may have double bonds,
which can vary in location
Carbon skeletons may be arranged in rings
Fig. 3.01
Carbohydrates “Sugars”
 Function
1. Dietary energy
2. Storage
3. Structural
 Named based on size
1. Monosaccharides (glucose & fructose)
2. Disaccharides (lactose & maltose)
3. Polysaccharides (starch & cellulose)
© 2013 Pearson Education, Inc.
C
Abbreviated structure of glucose
C6H12O6
Fig. 3.06b
Fig. 3.07
OH
H
Glucose
Galactose
H2O
Lactose
A disaccharide
Examples of Polysaccharides
Starch granules
in potato tuber cells
Glycogen granules
in muscle
tissue
(a) Starch
Glucose
monomer
(b) Glycogen
Cellulose microfibrils
in a plant cell wall
Cellulose
molecules
(c) Cellulose
Hydrogen bonds
Fig. 3.09
Lipids
 Function
1. Energy storage
2. Hormones
3. Insulation & Protection
 Don’t mix with water because they are non-polar
 Examples include
1. Fats (triglycerides)
2. Phospholipids
3. Steroids (testosterone and estrogen)
© 2013 Pearson Education, Inc.
Saturated Fats
TYPES OF FATS
Unsaturated Fats
Margarine
Plant oils
Trans fats
Omega-3 fats
Fig. 3.12
Cholesterol
Testosterone
can be converted
by the body to
A type of estrogen
Proteins
 Function
1. Enzymes
2. Structure & Storage
3. Contraction
4. Transport
 Examples
1. Lactase & hemoglobin
© 2013 Pearson Education, Inc.
MAJOR TYPES OF PROTEINS
Structural Proteins
(provide support)
Storage Proteins
(provide amino
acids for growth)
Contractile
Proteins
(help movement)
Transport Proteins
(help transport
substances)
Enzymes
(help chemical
reactions)
Amino
group
Carboxyl
group
Side
group
The general structure of an
amino acid
Hydrophobic
side group
Hydrophilic
side group
Leucine
Serine
Fig. 3.16
5
1
15
10
30
35
20
25
45
40
50
55
65
60
70
Amino acid
85
80
75
95
100
90
110
115
105
specific sequence of amino
acids in a protein is its
primary structure
125
120
129
Amino
acids
(b) Secondary structure
(c) Tertiary
structure
(d) Quaternary
structure
(a) Primary
structure
Pleated sheet
A protein with
four polypeptide
subunits
Hydrogen
bond
Polypeptide
Alpha helix
Fig. 3.20
Protein Shape – SUPER important
 A protein’s three-dimensional shape
1. typically recognizes and binds to another molecule
2. enables the protein to carry out its specific
function in a cell.
© 2013 Pearson Education, Inc.
SEM
Leu
1
2
3
4
5
6
7. . . 146
Normal hemoglobin
SEM
Normal red blood cell
Leu
1
Sickled red blood cell
2
3
4
5
6
7. . . 146
Sickle-cell hemoglobin
Fig. 3.19
Nucleic Acids
 Function
1. Store information
2. Provide instruction
 Examples
1. DNA & RNA
© 2013 Pearson Education, Inc.
G
C
Sugar-phosphate
backbone
Nucleotide
T
T
A
Base
pair
T
A
Hydrogen
bond
G
A
T
A
A
C
T
A
G
Bases
T
C
G
A
(a) DNA strand
(polynucleotide)
T
(b) Double helix
(two polynucleotide strands)
Large biological Functions
molecules
Carbohydrates
Components
Examples
Monosaccharides:
glucose, fructose;
Disaccharides:
lactose, sucrose;
Polysaccharides:
starch, cellulose
Dietary energy;
storage; plant
structure
Monosaccharide
Lipids
Proteins
Long-term
energy storage
(fats);
hormones
(steroids)
Enzymes,
structure,
storage,
contraction,
transport, etc.
Components of
a triglyceride
Side
group
Fats (triglycerides);
steroids
(testosterone,
estrogen)
Lactase
(an enzyme);
hemoglobin
(a transport protein)
Amino acid
Nucleic acids
Information
storage
T
Nucleotide
DNA, RNA