Transcript Macromolecules 2015 16

Macromolecules
Building Blocks
of Life
Macromolecules
• Smaller organic molecules join together to
form larger molecules
– macromolecules
• 4 major classes of
macromolecules:
– carbohydrates
– lipids
– proteins
– nucleic acids
Polymers
• Long molecules built by linking repeating
building blocks in a chain
– monomers
• building blocks
• repeated small units
H2O
– covalent bonds
HO
H
HO
H
Dehydration synthesis
HO
H
How to build a polymer
• Synthesis
– joins monomers by “taking” H2O out
• one monomer donates OH–
• other monomer donates H+
• together these form H2O
H2O
– Requires enzymes
HO
H
HO
H
enzyme
Dehydration synthesis
HO
H
How to break down a polymer
• Digestion
– use H2O to breakdown polymers
• reverse of dehydration synthesis
• cleave off one monomer at a time
• H2O is split into H+ and OH–
– H+ & OH– attach to ends
H2O
– requires enzymes
HO
enzyme
H
Hydrolysis
Digestion
HO
H
HO
H
CH2OH
H
HO
O
H
OH
H
H
OH
Carbohydrates
energy
molecules
2009-2010
H
OH
What are carbohydrates?
• Carbohydrates are
molecules made of sugars.
• A sugar contains carbon,
hydrogen, and oxygen in a
ratio of 1:2:1.
• Glucose is a common sugar
found in grape juice.
Simple & complex sugars
CH2OH
H
• Monosaccharides
• One sugar molecule
• glucose
• Disaccharides
– 2 sugars linked together
– sucrose
• Polysaccharides
– Many sugars linked
– starch
O
H
OH
H
H
OH
HO
Glucose
H
OH
Building sugars
• Dehydration synthesis
monosaccharides
disaccharide
H2O
|
glucose
|
glucose
|
maltose
glycosidic linkage
Building sugars
• Dehydration synthesis
monosaccharides
|
glucose
H2O
disaccharide
|
fructose
|
sucrose
(table sugar)
Polysaccharides
• Starch and glycogen store energy long-term
for plants or animals. They can be broken
down into simple sugars.
• Function:
– energy storage
• starch (plants)
• glycogen (animals)
– in liver & muscles
– structure
• cellulose (plants)
• chitin (arthropods & fungi)
Polysaccharides in plants and animals
starch
(plant)
energy
storage
glycogen
(animal)
Cellulose
• Most abundant organic
compound on Earth
– herbivores have evolved a mechanism to digest
cellulose
– most carnivores have not
• that’s why they
eat meat to get
their energy &
nutrients
• cellulose = undigestible roughage
Lipids
•long term energy storage
•concentrated energy
•Cushion organs
•Insulates Body
What are lipids? Why do they
taste good?
• They include the
butter, shortening,
oil, egg yolks, and
margarine that went
into the meal.
What are lipids made out of?
• Lipids include fats, phospholipids, steroids, and waxes.
• Lipids consist of chains of carbon atoms bonded to each other
and to hydrogen atoms. This structure makes lipids repel
water.
Building Blocks of Fats
H2O
dehydration synthesis
enzyme
H2O
enzyme
H2O
enzyme
HO
• Saturated:
• Unsaturated:
Phospholipids
• Structure:
– glycerol + 2 fatty acids + PO4
• PO4 = negatively charged
It’s just like me
A head at one end
& a tail
at the other!
Why is this important?
• Phospholipids create a barrier in water
– they make cell membranes!
What proteins do we eat at
Thanksgiving?
• This includes the turkey, egg whites, most of the milk, any
other meat and cheese.
Proteins
Are multipurpose molecules
Protein functions include:
1)structural support
2)storage
3)transport
4)cellular communications
5)movement
6)defense against foreign substances
2009-2010
What are proteins made of?
• A protein consists of one or more polypeptides
• Polypeptides are large molecules built from the
same set of 20 amino acids
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Amino Acids are the building blocks
that link to form proteins
Section 2-3
Amino
group
Carboxyl
group
General structure
Alanine
There are 20 Amino Acids
Go to
Section:
Serine
Building proteins
• Peptide bonds
– covalent bond between NH2 (amine) of one
amino acid & COOH (carboxyl) of another
– C–N bond
H2O
dehydration synthesis
peptide
bond
Protein structure (overview)
Folding to create an
overall shape
3°
multiple
polypeptides
1°
amino acid
sequence
peptide bonds
determined
by DNA
4°
2°
Localized
folding
Nucleic Acids
Information
storage
2009-2010
Nucleic Acids
• Function:
– genetic material
• stores information
– genes
– blueprint for building proteins
» DNA  RNA  proteins
DNA
• transfers information
– blueprint for new cells
– blueprint for next generation
proteins
What are nucleic acids?
• A nucleic acid is a long chain of nucleotide
units.
• A nucleotide is a molecule made up of
three parts: a sugar, a base, and a
phosphate group.
• Nucleotides of deoxyribonucleic acid, or
DNA, contain the sugar deoxyribose.
• Nucleotides of ribonucleic acid, or RNA,
contain the sugar ribose.
Nucleotides
• 3 parts
– nitrogen base (C-N ring)
– pentose sugar (5C)
• ribose in RNA
• deoxyribose in DNA
– phosphate (PO4) group
Nitrogen base
I’m the
A,T,C,G or U
part!
What are the Carbohydrates on
Thanksgiving?
• Mashed potatoes, stuffing, cornbread, sweet
potatoes, vegetables, fruits, sugars, syrups,
breads, pie crusts—big part of our
Thanksgiving.