Why Study Plants?
• Why not?
“To be useless, various, and
abstruse is sufficient
recommendation of a
science to make it pleasing
to me.”
William Harvey (1811-1866)
How do humans use plants?
Agricultural product as fodder
• Fodder- food that is fed
to domestic animals.
• Maize (Zea mays) is
the most important crop
in the United States.
– 80% of this crop is
consumed by animals.
What is the role of the photosynthetic
organism in the carbon cycle?
Global O2 from photosynthesis
• 80% comes from marine
cyanobacteria.
– Synechococcus
– Synechocystis
• 20% comes from terrestrial
systems.
– 5% of this comes from tropical
rainforests.
Photosynthetic organisms evolved 3.4 BYA and
are responsible for the biological revolution
• Increases in O2 from photosynthesis had 2
consequences:
– 1) Formation of ozone- O2 molecules in
atmosphere converted to ozone (O3).
• 2.5 BYA
– 2) Formation of aerobic atmosphere.
• Respiration- break down of molecules by oxidation.
• Eukaryotic cells- appearance and proliferation of
cells.
– 2.1 BYA
Summary of Photosynthesis
450
430
Phycobilins- 500-660
445 480
660
410
640
Light Reactions
Photorespiration
C4 Photosynthesis
How do animals use plants?
Primary Producers
Phytoremediation
• The treatment of pollutants
or waste by the use of plants
to break down undesirable
substances.
– Sunflowers
– Willow trees
– Pickleweed
Wastewater Treatment
• Lemna
gibbaduckweed.
• Eichornia
crassipeswater
hyacinth.
Biodiesel and Bioethanol from Plants
Plants in Space
• Chlorella- a unicellular green alga.
– Nutritional supplement.
– Process waste (urine).
– Life support system, O2.
Medicine in Ancient Times
• Otzi (3,350-3,140 BC)- frozen in
ice, found in the alps on the
Italian-Austrian border.
– Birch fungus used as a laxative and
as a natural antibiotic.
• The common herbs used in
Ancient Greece:
– Anise, black helebore, cassia,
cucumber, wild root of (squirting
cucumber), cumin, cyclamen, root of
frankincense, germander, lettuce,
wild myrrh, olive oil, opium, poppy,
parsnip, seseli.
Hippocrates (460-380 BC)
Father of medicine
• Ancient Greek physician for
the Medical School at Kos.
• Wrote Corpus Hippocraticum
Medicine in Modern Times
• 25% of the medicine on the market is
derived directly from plants.
• Drugs made from fungi prevent the
rejection of transplanted hearts and
other organs.
• The active ingredient in aspirin was
originally derived from willow bark.
• Paclitaxel, a compound found in the
Pacific yew tree, assists in the
treatment of some cancers.
• The rosy periwinkle helps treat
diabetes.
• Herbal remedies. Ginkgo biloba is
prescribed for depression, mental
weakness or confusion, loss of
memory, ringing of the ears.
Egyptian Papyrus
The Molecular Composition of Plant Cells
Chemical Elements
Metabolites
• Primary Metabolites- molecules found in
all plant cells.
• Secondary Metabolites- molecules
restricted in their distribution, both within
the plant and among different plants;
important for survival and propagation.
Macromolecule Synthesis and
Splitting
Carbohydrates
Lipids
Proteins
Acid group
Amino group
Nucleic Acids
Alkaloids
Terpenoids
Phenolics