3.7-3.8 Warm Up
1. Name and briefly describe the 3 polysaccharides.
2. How is cellulose unique?
3. What is a lipid?
4. Name the main function of fat.
5. Describe a triglyceride.
6. Differentiate saturated and unsaturated fat.
3.7 Polysaccharides are long chains of
sugar units
Tell me about starch...
an energy storage polysaccharide in plants
made entirely of glucose monomers
the molecule has a helical shape due to bond angles
between glucose units
Amylose (one component of starch)
What is glycogen?
an energy storage polysaccharide in animals
identical to starch except that it is more extensively
branched
most is stored in liver and muscle cells
Glycogen in the Liver
The Many Branches of Glycogen
Describe cellulose
most abundant organic compound on Earth
it forms a very strong cable-like fibril within the walls
that enclose plant cells
the fibril is composed of glucose chains that run
unbranched and parallel to each other, hydrogen
bonds form between the chains
Parallel Chains of Cellulose
Cellulose Fibers
Can you hydrolyze the glucose out of
cellulose?
no, most animals cannot break apart the bonds holding
the glucose molecules together
cows and termites have microorganisms in their
digestive tracts that break apart the glucose
monomers
mmmmm....... Cellulose
What is fiber? How does it help you?
fiber is cellulose in plant foods (oatmeal)
as fiber moves through your digestive tract, it pushes
everything out with it
Starch granules in
potato tuber cells
Glycogen granules in
muscle tissue
Cellulose fibrils in
a plant cell wall
Cellulose
molecules
Glucose
monomer
STARCH
GLYCOGEN
CELLULOSE
3.8 Lipids include fats, which are
mostly energy-storage molecules
Describe a lipid.
a molecule composed mainly of carbon and hydrogen
atoms (very few oxygen atoms)
contain mostly non-polar
covalent bonds
hydrophobic
What is a fat? Why do you need it?
fat is a large lipid made from
two smaller molecules:
a glycerol
fatty acids
fat is used primarily for
energy storage
The making of a Triglyceride
Saturated fat
Unsaturated fat
Saturated Fat
most animal fats are saturated (butter, lard)
form solids at room temperature
these fats can build up in your arteries and restrict
blood flow (atherosclerosis)
Lard
Atherosclerosis
Double Whammy
Unsaturated Fat
most plant oils are unsaturated (corn, olive, vegetable oil)
their double bonds act as kinks and prevent the
molecules from packing tightly enough to solidify
Homework:
Read 3.9-3.10
Packet Exercise 4