Microbes and Health

Question 1

Explain the historical changes and the significance of infectious disease in medicine

Answer 1

Pros- behavioral changes to avoid infection, improved nutrition to boost body defense, vaccination, antibiotics thwart epidemics
Cons- Drug abuse, poor food choice, transplant, more sex, travel, immunosuppresive therapy

Question 2

Differentiate the major classes of microorganisms: viruses, bacteria, fungi (two subclasses) and parasites

Answer 2

Viruses- not “living” immobile
Bacteria- prokaryotic, unicellular, motile
Fungi- eukaryotic multicellular immobile: yeast- unicellular: mold multicellular
Parasites- multicellular, eukaryotic, motile

Question 3

Describe major anatomical sites that are rich in normal flora

Answer 3

Females (4)- Skin (armpits), mouth, colon, vagina
Males (4)- skin (armpits), mouth, colon

Skin - S. epidermidis, P. aces
Saliva - Strept. mutans, Strept. salivarius
Colon - E. coli
Vagina - Lactobacilli

Question 4

Explain factors that affect the vaginal normal flora

Answer 4

Estrogen production- causes glycogen production in epithelial cells for Lactobacilli to thrive on and Lactobacilli prevents overgrowth of other bacteria by producing acid and antibiotics

Diabetes - increases blood sugar = growth of Candida albicans
Too much carbohydrates - growth of Candida albicans

Question 5

Explain symbiosis, ammensalism, commensalism, mutualism and parasitism

Answer 5

Symbiosis- two organisms living together
Ammensalism- one organism harmed other unaffected
Commensalism- one organism benefitted other unaffected
Mutualism- both organisms benefit
Parasitism- one organism harmed other benefits

Question 6

Explain host conditions that may turn normal flora to pathogens

Answer 6

Too many carbs being produced in vagina can cause overgrowth of Candida albicans (vaginal thrush)
Pregnant women- High estrogen- thrush
Diabetic women- high glucose- thrush
Insufficient Lactobacillus causing overgrowth of other bacteria

Question 7

Explain/describe characteristics of intracellular and extracellular organisms

Answer 7

Intracellular- hard to spread, easy to avoid host defense, not easily treated with drugs
Extracellular- Easy to spread, not easy to avoid host defenses, easily treated with drugs

Question 8

Compare and contrast the distinctive features of prokaryotic and eukaryotic cells

Answer 8

Prokaryotic cells- no nucleus, no membrane-bound organelles, single circular DNA, ~1000x smaller
Eukaryotic cells- nucleus, membrane-bound organelles, multiple linear DNA, larger in size

Question 9

Explain Koch’s postulate

Answer 9

1. ) Pathogen must be present in every case
2. ) Pathogen must be isolated from host and cultured
3. ) Cultured pathogen must cause disease when introduced to host organism
4. ) Pathogen must be isolated from inoculated host

Question 10

Explain/describe microparasites and macroparasites

Answer 10

Microparasites- able to multiply in a single host (life cycle entirely within one host)
Macroparasites- cannot multiply in one host (one or more phases of life cycle outside of host)