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AP Biology
Chapter 5.
Macromolecules
AP Biology
Macromolecules
Smaller organic molecules join together
to form larger molecules
macromolecules
4 major classes of macromolecules:
carbohydrates
lipids
proteins
nucleic acids
AP Biology
Polymers
Long molecules built by linking chain
of repeating smaller units
polymers
monomers = repeated small units
covalent bonds
AP Biology
How to build a polymer
Condensation reaction
dehydration synthesis
joins monomers by “taking” H2O out
1 monomer provides OH
the other monomer provides H
together these
form H2O
requires energy
& enzymes
AP Biology
How to break down a polymer
Hydrolysis
use H2O to break apart monomers
reverse of condensation reaction
H2O is split into H and OH
H & OH group attach where the covalent
bond used to be
ex: digestion is
hydrolysis
AP Biology
Carbohydrates
AP Biology
Carbohydrates
Carbohydrates are composed of C, H, O
carbo - hydr - ate
CH2O
(CH2O)x C6H12O6
Function:
1. energy 2. energy storage
3. raw materials 3. structural materials
Monomer: monosaccharides (sugars)
Polymer: polysaccharide
AP Biology
Carbohydrates include Sugars
Most names for sugars end in -ose
Classified by number of carbons
6C = hexose (glucose)
5C = pentose (fructose, ribose)
3C = triose (glyceraldehyde)
AP Biology
What functional groups?
carbonyl
ketone
aldehyde
hydroxyl
AP Biology
Sugar structure
5C & 6C sugars form rings in aqueous solutions
in cells!
Carbons are numbered
AP Biology
Numbered carbons
C
CC
C
C
C
1'
2'3'
4'
5'
6'
O
AP Biology
Simple & complex sugars
Monosaccharides (simple)
simple 1 monomer sugars
glucose
Disaccharides (simple)
2 monomers
sucrose
Polysaccharides (complex)
large polymers
starch
AP Biology
Building sugars
Dehydration synthesis
|
glucose
|
glucose
glycosidic linkage
monosaccharides disaccharide
|
maltose
AP Biology
Other examples:
• Sucrose = glucose + fructose
• Maltose = glucose + glucose
• Lactose = glucose + galactose
AP Biology
Polysaccharides
Polymers of sugars
costs little energy to build
easily reversible = release energy
Function:
1. energy storage starch (plants)
glycogen (animals)
2. building materials = structure cellulose (plants)
chitin (arthropods & fungi)
AP Biology
POLYSACCHARIDES~ “many sugars”
Ex: STARCH • polymer of αlpha glucose • linked by α 1-4 glycosidic linkages
Function: Energy storage in PLANTSMost animals have the enzymes to hydrolyze
starch, toohttp://www.langara.bc.ca/biology/mario/Assets/Amylopectin.jpg
http://www.district87.org/biology87/apbio/biochem/Activity6_notes.pdf
AP Biology
POLYSACCHARIDES~ “many sugars”
TWO KINDS OF STARCH:amylose = unbranched starch
amylopectin = branched starch
http://www.langara.bc.ca/biology/mario/Assets/Amylopectin.jpg
AP Biology
POLYSACCHARIDES~ “many sugars”
EX: GLYCOGENalpha 1-4 glycosidic bonds like starchMore branched than amylopectin
FUNCTION:Energy storage in ANIMALS
Stored in liver and muscle tissue
http://www.abcbodybuilding.com/magazine04/scientific.htm
AP Biology
POLYSACCHARIDES~ “many sugars”
Example: CELLULOSE (PLANTS ) FUNCTION: Structural
Major component in cell wallsMost abundant organic compound on Earthbeta (ß) 1-4 glycosidic linkages
AP Biology
• Enzymes that digest starch by hydrolyzing alpha linkages can’t hydrolyze beta linkages in cellulose
• Cellulose in human food passes through the digestive tract as insoluble fiber
• Some microbes use enzymes to digest cellulose• Many herbivores, from cows to termites, have symbiotic
relationships with these microbes
AP Biology
POLYSACCHARIDES
EX: CHITIN
FUNCTION: StructuralStructural polysaccharide made from ß glucose with a NITROGEN containing group attached
AP Biology
Major component of:Exoskeletons in Arthropods
Cell walls in Fungi Dissolvable surgical thread
AP Biology
Lipids: Fats & Oils
AP Biology 2006-2007
Lipidslong term energy storage
concentrated energy
AP Biology
Lipids
Lipids are composed of C, H, O
long hydrocarbon chains (H-C)
“Family groups”
fats
phospholipids
steroids
Do not form polymers
big molecules made of smaller subunits
not a continuing chain
AP Biology
Fats
Structure:
glycerol (3C alcohol) + fatty acid
fatty acid =
long HC “tail” with carboxyl (COOH) group “head”
dehydration synthesis
H2O
enzyme
AP Biology
Building Fats
Triacylglycerol (trigyceride)
3 fatty acids linked to glycerol
ester linkage = between OH & COOH hydroxyl carboxyl
AP Biology
Dehydration synthesis
dehydration synthesis
H2O
H2O
H2O
H2O
enzyme
enzyme
enzyme
AP Biology
Fats store energy
Long HC chain
polar or non-polar?
hydrophilic or hydrophobic?
Function:
energy storage
concentrated
all H-C!
2x carbohydrates
cushion organs
insulates body
think whale blubber!
Why do humanslike fatty foods?
AP Biology
Saturated fats
All C bonded to H
No C=C double bonds
long, straight chain
most animal fats
solid at room temp.
contributes to
cardiovascular disease
(atherosclerosis)
= plaque deposits
AP Biology
Unsaturated fats
C=C double bonds in
the fatty acids
plant & fish fats
vegetable oils
liquid at room temperature
the kinks made by double
bonded C prevent the
molecules from packing
tightly together
mono-unsaturated?poly-unsaturated?
AP Biology
Saturated vs. unsaturated
saturated unsaturated
AP Biology
Phospholipids
Structure:
glycerol + 2 fatty acids + PO4
PO4 = negatively charged
It’s just like apenguin…
A head at one end& a tail
at the other!
AP Biology
Phospholipids
Hydrophobic or hydrophilic?
fatty acid tails =
PO4 head =
split “personality”
interaction with H2O
is complex & very
important!“repelled by water”
“attracted to water”
Come here,No, go away!Come here,No, go away!
hydrophobic
hydrophillic
AP Biology
Phospholipids in water
Hydrophilic heads “attracted” to H2O
Hydrophobic tails “hide” from H2O
can self-assemble into “bubbles”
bubble = “micelle”
can also form a phospholipid bilayer
early evolutionary stage of cell?
bilayer
water
water
AP Biology
Why is this important?
Phospholipids create a barrier in water
define outside vs. inside
they make cell membranes!
Tell themabout soap!
AP Biology
Steroids
Structure:
4 fused C rings + ??
different steroids created by attaching different
functional groups to rings
different structure creates different function
examples: cholesterol, sex hormones
cholesterol
AP Biology
Cholesterol
Important cell component
animal cell membranes
precursor of all other steroids
including vertebrate sex hormones
high levels in blood may contribute to
cardiovascular disease
AP Biology
Cholesterol
helps keep
cell membranes
fluid & flexible
Important component of cell membrane
AP Biology
From Cholesterol Sex Hormones What a big difference a few atoms can make!
AP Biology 2006-2007
Let’s build some
Lipids!
AP Biology 2007-2008
Ghosts of Lectures Past
(storage)
AP Biology
Phospholipids & cells
Phospholipids of cell membrane double layer = bilayer
hydrophilic heads on outside in contact with aqueous solution outside of
cell and inside of cell
hydrophobic tails on inside form core
forms barrier between cell & external environment
Tell themabout soap!