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Macromolecules
Building Complex
Molecules That
Comprise Living Things
Comparison of Terms
Molecule
Two or more atoms joined by
chemical bonds
Macromolecule Large polymer made of
repeating monomer units
Four types of organic macromolecules
are important in living systems.
Macromolecules: Polymers
Made of Repeating Monomers
Macromolecule
Monomer Subunit
Carbohydrates
Simple Sugars
Lipids
Proteins
Fatty acids and glycerol
Nucleic Acids
Nucleotides
Amino acids
Organic Macromolecules
Contain Carbon
Question: How many
electrons does carbon need
to fill its outer energy level?
Answer: Four
Each carbon atom can make four
covalent bonds with other types of
atoms or additional carbons.
Synthesis and Breakdown of
Macromolecules
Dehydration
Synthesis
Hydrolysis
Removal of water to add
monomer units
Addition of OH and H
groups of water to break
a bond between
monomers
Dehydration Synthesis / Hydrolysis
Dehydration Synthesis
Hydrolysis
Carbohydrates: Structure
• Simple
– Monosaccharides= one sugar unit
Glucose = blood sugar
All cells use glucose for energy
Carbohydrates: Structure
• Simple
– Disaccharides = two sugar units
CH2OH
HOCH2 O H
O
H
H
+
H
H HO
OH H
CH2OH
HO
OH HO
HO
H
H HO
Glucose + Fructose
CH2OH
H
HOCH2
O
O
H
H
H HO
H
OH H
O
HO
CH2OH
H
H HO HOH HO
Sucrose & Water
Carbohydrates: Structure
• Simple
– Disaccharides = two sugar units
• Sucrose = glucose + fructose
table sugar
• Lactose = glucose + galactose
milk sugar
• Maltose = glucose + glucose
seed sugar
Carbohydrates: Structure
• Complex
– Polysaccharides= many sugar units
• Starch -- storage in plants
• Glycogen -- storage in animals
• Cellulose -- plant cell walls, indigestible
• Chitin -- exoskeletons of insects,
fungal cell walls
Chitin
Carbohydrates: Functions
• Energy source
• Structural component
• Cell-cell communication
Carbohydrates: Dietary
Recommendations
• 58% of calories from carbohydrates
• No more than 10% of calories from simple,
refined sugars
• Emphasize
– Complex Carbohydrates
• Starch
• Fiber (cellulose)
– Naturally-occurring simple carbohydrates
• Fructose from fruit
• Lactose from milk
Macronutrients As
Energy Sources
Applying Your Knowledge
1. Monosaccharide
2. Polysaccharide
3. Disacharide
A. Which molecule consists of two sugar
units?
B. Which choice best describes glycogen?
C. Which type of molecule provides the
basic energy for your cells?
D. Which type of molecule is found in
milk?
Macromolecules: Polymers
Made of Repeating Monomers
Macromolecule
Monomer Unit
Lipids
(fats, oils, waxes)
Glycerol and
Fatty acids
Lipids: Structure
• Triglyceride—predominant form in diet
– One molecule of glycerol
– Three fatty acids
Lipids: Structure
• Types of Fatty Acids
– Saturated – 2H per internal carbon
– Unsaturated -- <2H per internal carbon
one or more double bonds
• Monounsaturated – one double bond
• Polyunsaturated – more than one double bond
Triglyceride
Formation
H
Glycerol
Remove
These
Waters
Add 3
Fatty
Acids
HC
OH
OH
C O
HCH
HCH
HCH
H
H
Triglyceride
H
C
CH
OH
OH
OH
OH
C O C O
HCH HCH
HCH HCH
HCH HCH
H
H
H
H
H
HC
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
C
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
CH
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
3 Waters
Which Is a Source of Unsaturated Fatty Acids?
Linseed Oil
Beef Fat
Lipids: Structure
•Phospholipid—component of cell membranes
Polar
Head
Glycerol
Hydrophilic
Fatty Acid Tails
Hydrophobic
Lipids: Structure
• Steroids
– Linked carbon rings
– Natural body components
• Hormones
• Cholesterol
Steroids
Cholesterol
Estradiol
Testosterone
Lipids: Functions
• Concentrated energy source
• Structural components of cell
membranes
– Phospholipids
– Cholesterol
• Communication
– Steroid Hormones
• Protection from water
– Waxes
Cholesterol
Phospholipids
Lipids: Dietary Recommendations
•
•
•
•
< 30% of calories from lipids
< 10% of calories from saturated fats
Limit cholesterol to 300 mg/day
Avoid “trans” fatty acids in partially
hydrogenated products
• Emphasize
– Unsaturated fatty acids from
vegetables, fish, legumes, and nuts
– Oils: mono- or polyunsaturated
Macronutrients As
Energy Sources
Applying Your Knowledge
1.
2.
3.
4.
Polyunsaturated fatty acid
Cholesterol
Monounsaturated fatty acid
Saturated fatty acid
A. Which molecule is made of a series of
carbon rings?
B. Which molecule has more than one
double bond?
C. Which molecule has 2H for each
internal carbon?
D. Which molecule has one double bond?
Macromolecules: Polymers
Made of Repeating Monomers
Macromolecule Monomer Unit
Protein
Amino acids
Proteins: Structure
• Primary structure = chain of amino acids
– Amino acids have common features
Carboxylic Acid
Group
Amino
Group
R
“Alpha”
Carbon
The “R” Group
Differs for Each Amino Acid
Amino Acids: Phenylalanine Structure
Amino
Group
Carboxylic Acid
Group
“Alpha”
Carbon
Phenylalanine
“R” Group
Amino Acids: Leucine Structure
Amino
Group
Carboxylic Acid
Group
Leucine “R”
Group
Proteins: Structure
Forming the Protein Chain
Phenylalanine
Leucine
Dehydration Synthesis
between COOH & NH2
Proteins: Structure
Forming the Protein Chain
The Peptide Bond
Water
Phenylalanine-Leucine Dipeptide
Four Levels of Protein Structure
Primary
(Sequence)
Tertiary
(Folding by
R-group
interactions)
Quaternary
(Two or more chains
associating)
Secondary
(Coiling by
Hydrogen Bonding)
Four Levels of Protein Structure
Primary Structure = sequence of amino acids in chain
Four Levels of Protein Structure
• Secondary Structure
Folded structure due to hydrogen bonds
between the amino and acid groups of amino
acids
N
C
H
O
O
C
N
C
H
O
H
O
H
N
C
N
or
Found in most proteins
Found in silk
Four Levels of Protein Structure
• Tertiary Structure:
Three dimensional folded structure due to
attractions and repulsions between R groups
Can involve
covalent bonding
hydrogen bonding
ionic interactions
hydrophilic and hydrophobic interactions
Hair Curling
S
|
S
|
|
|
S
|
S
|
S
|
|
S
Straight
Hair
|
S
|
S
S
|
S
|
|
|
|
Naturally
Curly
Hair
Four Levels of Protein Structure
• Quaternary Structure:
Association of two or more protein
chains
eg. Hemoglobin is composed
of 4 protein chains
2 are called alpha
hemoglobin
2 are called beta
hemoglobin
Proteins: Functions
•
•
•
•
Structural Component of Cells
Control of Metabolic Reactions: enzymes
Growth and Repair
Communication
– Protein Hormones
– Cell Receptors
• Energy source
Protein
Protein
Proteins: Dietary
Recommendations
• 12% of calories from proteins
• 8 essential amino acids obtained
from
–Lean sources of animal protein
–Complementary plant proteins
• Beans + Grains
• Beans + Seeds
Applying Your Knowledge
1.
2.
3.
4.
Primary
Secondary
Tertiary
Quaternary
A. Which structure results from hydrogen
bonding?
B. Which structure involves an association of
two or more protein chains?
C. Which structure describes the linear
sequence of amino acids?
D. Which structure depends upon interactions
between the R groups of the amino acids?