Download Macromolecules

Macromolecules
Building Complex Molecules
That Comprise Living Things
Macromolecules: Polymers
Made of Repeating Monomers
Macromolecule Monomer Unit
Carbohydrates
Sugars
Lipids
Proteins
Fatty acids
Nucleic Acids
Nucleotides
Amino acids
Carbohydrates: Structure
• Simple
– Monosaccharides= one sugar unit
Glucose = blood sugar
All cells use glucose for
energy.
Carbohydrates: Structure
• Simple
– Disaccharides = two sugar units
Glycosidic Linkage
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
• Complex
– Polysaccharides= many sugar units
found in plant cell walls
energy storage
in plants
energy storage
in animals
Chemically- Modified
Carbohydrates
Sugar
Phosphate
Amino Sugars
Galactosamine is
found in cartilage
Amino Sugar
Chiton forms the
exoskeleton of insects
Carbohydrates: Functions
• Energy source
• Source of carbon skeletons for synthesis
of other biological molecules
• Structural component of cells
• Cell-cell communication
Eating Any Carbs Lately?
How can
I use this
info?
• Nutritionists recommend that carbohydrates
be included as an important energy source
in the diet
• Emphasize
– Complex Carbohydrates
• Starch
• Fiber (cellulose)
Whole Grains
– Naturally-occurring simple carbohydrates
• Fructose from fruit
• Lactose from milk
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
Ester
Linkage
H
C
CH
OH
OH
OH
OH
C O C O
HCH HCH
HCH HCH
HCH HCH
H
H
Triglyceride
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
– Used to produce
• Hormones
• Cholesterol
• Vitamin D2
Testosterone
Lipids: Functions
• Concentrated energy source
• Structural components of cell membranes
– Phospholipids
– Cholesterol
• Carotenoids capture light
energy for photosynthesis
• Communication
– Steroid Hormones
• Metabolism
– Fat-soluble vitamins
Cholesterol
• Insulation
Phospholipids
• Protection from water
– Waxes
High Fat, Low Fat, No Fat…
•
•
•
•
How can
I use this
info?
Limit fats to < 30% of calories
Limit saturated fats to < 10% of calories
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
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
Proteins: Structure
Forming the Protein Chain
Phenylalanine
Leucine
Dehydration Synthesis
between COOH & NH2
Proteins: Structure
Forming the Protein Chain
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)
Protein Folding Within the Cell
• Proteins called chaperonins assist in proper
folding of newly synthesized proteins
• Some chaperonins “trap” proteins in a
molecular cage to prevent interference in the
folding process
Four Levels of Protein Structure
Primary Structure = sequence of amino acids in chain
Carboxyl
Terminus
Amino
Terminus
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
Interactions in Tertiary Structure
Ionic
Bonding
Hydrogen Bonding
Hydrophobic
Effect
van der Waals forces
Disulfide Bridge
(covalent bond)
Maintaining Protein Structure
• Denaturation disrupts tertiary and secondary
structure and is not usually reversible
• Denaturation can be caused by heat, pH
changes and other chemicals such as salts or
charged ions
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
Transport
Protection and Support
Movement
Growth and Repair
Defense Against Disease
Communication/Regulation
– Protein Hormones
– Cell Receptors
• Energy source
Protein
Protein
For the Remaining Calories…
How can
I use this
info?
• Protein requirements are based on
body size and needs for growth
• 8 essential amino acids obtained
from
–Lean sources of animal protein
–Complementary plant proteins
• Beans + Grains
• Beans + Seeds