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Microbiology > Chapter 5: Part 2 > Flashcards

Chapter 5: Part 2 Flashcards

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Biology 101 flashcards
1
Q

Protozoa (member of the protist family)

A
  • Eukaryotic cells; diverse group of 65000 species, vary in shape, lack a cell wall
  • Chemoheterotophic; lack chloroplasts
  • Unicellular; rarely colonial
  • Most are harmless, free-living in a moist habitat (aquatic, damp soil)
  • Some are animal parasites (human tissue habitat) and can be spread by insect vectors
  • Cytoplasm divided into ectoplasm and endoplasm
  • Feed by engulfing other microbes and organic matter
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2
Q

Cyst

A

protected structure; contains larval stage

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3
Q

Vegetative Form

A

active: Trophozoite

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4
Q

Definitive Host

A

final host; harbors the adult

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5
Q

Intermediate Host

A

secondary host; harbors a larval or intermediate form of parasite

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6
Q

Infective Form

A

egg, larva, cyst, trophozoite (how it gets to you)

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7
Q

Diagnostic Form

A

present in stool, migrates out of body

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8
Q

Mechanical Vector

A

Passive

  • passed on outside; not in body;fly goes on poop–>poop then lands on sandwich (hitches a ride); does not spend time in life cycle
  • non-specific
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9
Q

Biological Vector

A

Active

  • spend life cycle in vector (host)
  • specific
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10
Q

General Life Cycle Exhibited by Many Protozoa

A
  1. Cell rounds up, loses motility; drying, ;lack of nutrients
  2. Early cyst wall formation (encystment)
  3. Mature cyst (dormant, resting stage)
  4. Moisture, nutrients restored; cyst wall breaks open (excystment)
  5. Tropozoite is reactivated
  6. Trophozoite (active feeding stage)
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11
Q

Protozoan Identification

A

Classification is difficult because of diversity

  • Simple grouping usually based on method of motility, reproduction, and life cycle
    1. Mastigophora
    2. Sarcodina
    3. Ciliophora
    4. Apicomplexa
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12
Q

Protozoan Identification: Mastigophora

A

primarily flagellar motility, some flagellar and amoeboid; sexual reproduction (flagellate)

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13
Q

Protozoan Identification: Sarcodina

A

primarily amoeba; asexual by fission; most are free-living; move by pseudopods

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14
Q

Protozoan Identification: Ciliophora

A

cilia; trophozoites and cysts; most are free-living, harmless

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15
Q

Protozoan Identification: Apicomplexa

A

motility is absent except male gametes; sexual and asexual reproduction; complex life cycle- all parasitic

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16
Q

Amoeboid Protozoa

A

Amoebiasis: Entamoeba histolytica
-reservoir/ source: Human/ water and food
Brain Infection: Naegleria, Acanthamoeba- free living in water

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17
Q

Infective Amoebas

A

Entamoeba histolytica- amoebic dysentery (bloody, pus diarrhea); worldwide

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18
Q

Ciliated Protozoa

A

(ciliophora)

Balantidiosis: Balantidium coli- zoonotic in pigs

19
Q

Flagellated Protozoa

A

(mastigophora)

  • Giardiasis: Giardia lamblia; reservoir/ source- zoonotic/water and food
  • Trichomoniasis: T. hominis, T.vaginalis; reservoir/ source- humans
  • Hemoflagellates
  • Trypanosomiasis: Trypanosoma brucei, T. cruzi
  • Leishmaniasis: Leishmania donovani, L. tropica, L. brasiliensis; reservoir/source- zoonotic/vector-borne
20
Q

Apicomplexan Protozoa

A
  • Malaria: Plasmodium vivax, P. falciparum, P. malariae; reservoir/ source- human/vector-borne
  • Toxoplasmosis; Toxoplasma gondii; reservoir/ source- zoonotic/ vector-borne
  • Cryptosporidiosis: Cryptosporidium; free-living/water and food
  • Cyclosporiasis: Cyclospora cayetanensis; water/ fresh produce
21
Q

Trypanosoma spp.: Trypanosoma brucei

A
  • causes African Trypanosomiasis or African sleeping sickness
  • vector: Glossina (Tsetse Fly)
  • Central Nervous System Disease (coma)
22
Q

Trypanosoma spp.: Trypanosoma cruzi

A
  • causes American Trypanosomiasis or Chagas Disease
  • Vector: Triatoma infestants (kissing bug)
  • Cardiovascular Disease
23
Q

Trypanosoma brucei Strains

A
  • Trypanosoma brucei brucei: Equines, pigs, cattle, rodents
  • Trypanosoma brucei gambiense: Humans, monkeys, dogs, pigs, antelopes: West and Central Africa
  • Trypanosoma brucei rhodesiense: humans, wild game, pigs, rats(experiments); East and Central Africa
24
Q

Trypanosoma brucei Strains: Trypanosoma brucei brucei

A

equines, pigs, cattle, rodents

25
Q

Trypanosoma brucei Strains: Trypanosoma brucei gambiense

A

humans, monkeys, dogs, pigs, antelopes

-West and Central Africa

26
Q

Trypanosoma brucei Strains: Trypanosoma brucei rhodesiense

A

humans, wild game, pigs, rats(experiments)

-East and Central Africa

27
Q

Life Cycle: Toxoplasma gondii

A
  1. infected raw meat, rodents, birds, other animals, and contaminated soil contain Toxoplasma gondii trophozoites and/ or cysts
  2. Oocysts in urine and feces; cat consumes raw meat or contaminated soil. Parasite undergoes sexual reproduction only in cats
  3. Oocysts in cat urine and feces further mature into sporocysts in litter box, sandbox, or soil
  4. infected pregnant woman transmits T. gondii infection to fetus
  5. Congenital defects: brain damage, blindness, and mental retardation due to destruction by feeding trophozoites
  6. immunocompromised patients may develop severe CNS damage or seizures or may die
28
Q

Sandfly Transmission Cycle

A
  • Human, other mammalian host
  • Free and intracellular amastigotes in a macrophage
  • sand fly becomes infected by biting host
  • promastigote stages in the gut of the sand fly
29
Q

Helminths

A
  • eukaryotic
  • multicellular animals
  • Phylum Platyhelminthes: flat worms
  • Phylum Nematoda: round worms
30
Q

Phylum Platyhelminthes

A
  • flat worms; no body cavity
  • incomplete digestive system
  • mostly monoecious (hermaphroditic)
  • greatly reduced systems except reproductive
  • very efficient reproductive system (eggs and sperm)
  • Classification:
    1. Class Turbellaria: free living
    2. Class Cestode: tapeworms
    3. Class Trematode: flukes
31
Q

Phylum Platyhelminthes: Class Turbellaria

A

free living

32
Q

Phylum Platyhelminthes: Class Cestode

A

tapeworms

33
Q

Phylum Platyhelminthes: Class Trematode

A

flukes

34
Q

Helminth Classification and Identification

A
  • classify according to shape, size, organ development, presence of hooks, suckers, or other special structures, mode of reproduction, hosts, and appearance of eggs and larvae
  • identify by microscopic detection of worm, larvae, or eggs
35
Q

Monoecious

A

in 1 body there is both sets of sex organisms (ovaries + testes in 1 organism)

36
Q

Dioecious

A

2 houses; 1 male 1 female

37
Q

Life Cycle: Schistosoma japonicum (blood fluke)

A

schistosomiasis
-exception: Reproduction- dioecious
-exception: mode of transmission- penetration of skin
1. fertilized eggs leave intestinal wall and pass to outside in feces
2. eggs hatch in water
3. free swimming miracidium enters snail (alternate host) and develops into a sporocyst
4. sporocyst develop into cercaria and are released into water
5. cercaria enter the body, lose their tails, and encyst as metacercaria
6.maturation into adult worm occurs
7. worms mate and lay eggs in hepatic portal blood vessels
8. male worm holds female within a cleft in his body
Cycle starts again

38
Q

Cestodes

A 
Tapeworms
Classification
-Structure: scolex, proglottids
-Scolex- has hooks and/or suckers
-Proglottids- body segments
-both male and female organs in each proglottid: hermaphroditic aka monoecious
-Newest segments near the head 
-Older segments come out with feces
39
Q

Cestodes: Scolex

A

head

-has hooks and/ or suckers

40
Q

Cestodes: Proglottids

A

body segments

  • both male and female organs in each proglottid: hermaphroditic aka monoecious
  • Newest segments near the head
  • Older segments come out with feces
41
Q

Life Cycle of Beef Tapeworm

A

Taeia saginata
Disease: Taeniasis
1. Eggs are passed in feces along with egg-filled proglottid
2. feces disintegrate, leaving eggs on grass
3. cow becomes infected when it eats contaminated grass
4. eggs hatch; larvae burrow through intestinal wall, enter bloodstream, and encyst in muscles as cysticerci
5. cysticercus (infective embryo in meat)
6. Cysticerci are ingested in rare or undercooked meat
7. adult worm attaches to mucosa of small intestine
8. new proglottids form immediately behind scolex. Old proglottids break off at the far end of worm, then eggs are passed again

42
Q

Phylum Nematoda

A
  • roundworms
  • nonsegmented (smooth)
  • Reproduction: dioecious; sexual and internal
  • sexual dimorphic
  • Habitats: marine, freshwater, damp soil, moist plant tissues, animal tissues
  • Size: less than 1 mm to more than a meter (blunt at anterior end; tip at posterior
43
Q

Life Cycle of pinworm Enterobius vermicularis

A
  • mode of transmission: ingestion (ingest eggs)
  • eggs into mouth
  • go into intestines to mature
  • male + female mate
  • female migrates out through anus + lay eggs (can wiggle back into body) (symptom- itchy butt)
44
Q

Distribution and Importance of Parasitic Worms

A
  • approximately 50 species parasitize humans
  • distributed worldwide; some restricted to certain geographic regions with higher incidence in tropics
  • primarily acquired through ingestion of larvae or eggs in food; from soil or water;
  • exception: larvae penetrate the skin; some are carried by vectors
  • afflict billions of humans

Microbiology (20 decks)

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