Fighting Disease
Review the sections in the Diversity and Kingdoms lab that talk about bacteria and Gram Staining, and antibiotic sensitivity.
One plant adaptation important to the survival and early dominance of flowering plants is the production of secondary plant metabolites. These bad tasting and sometimes toxic compounds have been one of plants most powerful means of defense. These compounds can be divided into six easily identifiable classes based on plant material and extract. The table below lists each compound and how they affect vertebrates in general.
| SECONDARY COMPOUND | HUMAN PHARMACOLOGICAL EFFECTS |
| Alkaloids | Antibacterial, stimulants, |
| sedatives, vaso-constrictors & | |
| dilators, diuretics, | |
| expectorants, antidiarrheal | |
| Cyanogenic glycosides | cough suppressants, treatment |
| of digestive disorders | |
| Saponins | expectorant, diuretic; treatment |
| of skin diseases, anemia & diabetes | |
| Cardiac glycosides | Regulation of heart activity |
| Tannins | Astringent used in treating |
| cuts & burns, antidiarrheal | |
| Simple phenolics | Antihelmenthics, antiseptics |
| analgesics, diuretics |
In this lab, six different New Mexico plants were tested for the presence of alkaloids, saponins, tannins, phenolics, and antimicrobial activity. The plants of interest are bindweed, horsemint, nightshade, sunflower, tansy and willow.
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Bindweed Convolvulaceae Family Convolvulus arvensis |
|
Horsemint Lamiaceae Family Monarda punctata |
 |
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Silverleaf Nightshade Solanaceae Family Solanum elaeagnifolium |
|
Sunflower Asteraceae Family Helianthus annuus |
 |
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Tansy Mustard Brassicaceae Family Descurainia pinnata |
|
Coyote Willow Salicaceae Family Salix exigua |
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Review Questions
- Name 3 differences between viruses and bacteria.
- Explain why antibiotics do no work against viruses.
- Explain how a virus reproduces.
- What is the main difference between antiseptics and disinfectants?
- What does it mean if an antibiotic is narrow-spectrum?
- What are secondary metabolites? Give and example of one. Why do
plants produce them?
- Name the 2 major types of immune defenses, describe how they differ, and give
an example of defensive agents (cell, organ, action, etc.) of each type.
- When cells rupture or burst, what is this called?
- When a white blood cell engulfs bacteria and foreign material, what is this
called?
- What are the 4 critical stages to each immune response?
- What is a bacterial cell wall made up of?
- What does a gram negative cell wall have, that a gram positive cell wall does
not?
- How can you treat viruses?
- What is a broad spectrum antibiotic?
- ______________are used to fight bacteria on living organisms and __________
are used to fight bacteria on non-living surfaces.