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MACROMOLECULES
A Brief Review
•What are the 4 major macromolecules?
•How are they made or broken down?
•What are they made of?
•What are they used for?
Macromolecule Basics:
• “MACRO-” = LARGE
• large biological molecules
• “building blocks” for life
• 4 macromolecules:
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•
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Carbohydrates
Lipids
Proteins
Nucleic acids
• All but lipids are POLYMERS
• Polymer - a long molecule consisting of many similar
building blocks (monomers) linked by covalent bonds
• Monomer – repeating units of a polymer
• ANALOGY = a train
How are
macromolecules
made and broken
down?
• Synthesis = made
• Dehydration (condensation)
reaction – 2 monomers are
covalently bonded together
through a LOSS of a WATER
molecule
• Decomposition = broken down
• Hydrolysis (hydration) – covalent
bonds between monomers are
broken by the ADDITION of
WATER
• Reverse of dehydration!
CARBOHYDRATES
• AKA: “sugars”,
saccharides
• Serve as FUELS,
sources of carbon, and
structural support
• Composed of “CHO”
• Name ends in “-ose”
• 2 trademarks of
sugars:
• a carbonyl group (>C=O)
• multiple hydroxide
groups (-OH)
GLUCOSE
CARBOHYDRATES
• Carbs can be classified by
the number of monomers
that comprise the sugar:
• Monosaccharides - “simple
sugars”
• Examples: glucose; fructose;
galactose
Reaction??
• Disaccharides – consists of 2
monosaccharides
• glucose + glucose = maltose
• glucose + fructose = sucrose
• Polysaccharides (“complex
carbs”) – consists of many
monosaccharides (usually more
than 8)
• examples: starch or glycogen
LIPIDS
• LARGE molecules
that are not
polymers!
?
• All are hydrophobic
& consist mostly of
hydrocarbons.
• Composed mostly of
“CHO”
• Have less oxygen
atoms than carbs.
?
Types of LIPIDS:
• 3 major groups:
• Triglycerides – “fats” & “oils”
• FUNCTIONS: long-term energy storage,
protection, & insulation.
• Made up of:
• 1 glycerol – an alcohol
AND
• 3 fatty acids – long C skeleton (of
hydrocarbons) + a carboxyl group
• Saturated vs. unsaturated fats/oils?
• Phospholipids –
• Function: major component of cell
membranes!!!!
• Structure:
• similar to triglycerides, but only has 2
fatty acid tails
• “TAIL” – nonpolar; hydrophobic
• 3rd hydroxyl group is attached to a
phosphate group
• “HEAD” – polar; hydrophilic
• Steroids –
• Structure: characterized by 4 fused rings
of carbon skeletons
• Functions: regulate growth &
development (hormones)
PROTEINS
basic structure
R = ??
Amine group?
Carboxyl
group?
• Account for approx. 50% of
the dry mass of cells!
• Composed mostly of “CHON”
• Basic structure??
• Proteins consist of one or
more polypeptides folded
and coiled into specific
conformations (shapes).
• Polypeptides are polymers
of amino acids.
Amino acids  polypeptides
 protein
The MANY Functions of Proteins!
• Structural support (collagen & elastin make connective
tissues; keratin makes hair, feathers, & horns)
• Energy storage (ovalbumin-egg whites; casein-milk;
plants & seeds)
• Transport of other substances (hemoglobin and red blood
cells)
• Signaling within an organism (nerve cell transmission;
insulin-regulates blood sugar)
• Movement (actin & myosin-muscle contraction)
• Defense against disease (antibodies)
• As ENZYMES: regulates metabolism (catalase-breaks
down H2O2)
Nucleic Acids
• Composed mostly of
“CHONP”
• Are composed of monomers
called nucleotides.
• Each nucleotide
contains:
• A nitrogenous base (N)
• A pentose (CHO)
• A phosphate group (P)
• 2 types of nucleic acids:
• Deoxyribonucleic acid (DNA)
• Ribonucleic acid (RNA)