Unit 4 - Part 9 Protozoa Flashcards

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1
Q

What are the two main stages in the life cycle of cysts or occyst-forming protozoa?

A
  1. Trophozoites

2. Cysts or oocysts

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2
Q

What is the active feeding stage of protozoa?

A

Trophozoites

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3
Q

How do trophozoites reproduce?

A

Asexually by binary fission

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4
Q

True or False:

Cysts are metabolically active

A

False

- cysts are metabolically inactive

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5
Q

True or False:

Oocysts are the products of sexual reproduction

A

True

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6
Q

What three things can cysts AND oocysts do?

A
  1. Remain infective/infectious outside the hosts
  2. Survive the environment for a long time
  3. May be involved in reproduction
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7
Q

Describe the stages involved where a trophozoite forms into a cyst

A
  1. Trophozoite (active, feeding)
  2. Drying, lack of nutrients - cell rounds up, loses motility
  3. Early cyst wall formation
  4. Mature cyst (dormant, resting stage)
  5. Moisture, nutrients restored
  6. Cyst wall breaks open
  7. Trophozoite is reactivated
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8
Q

True or False:

Both simple and complex reproductive strategies are observed among protozoa

A

True

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9
Q

True or False:

Some protozoa only asexually reproduce while others only sexually reproduce

A

False

  • some reproduce only asexually
  • others reproduce BOTH sexually and asexually!
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10
Q

What are the two methods that protozoa can reproduce asexually?

A
  1. Binary fission

2. Multiple fission

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11
Q

What happens in binary fission?

A

A parent cell gives rise to TWO daughter cells

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12
Q

What happens in multiple fission (also called schizogony)?

A

A parent cell gives rise to multiple daughter cells

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13
Q

What are the 3 names for a parent cell?

A
  • Schizont
  • Meront
  • Segmenter
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14
Q

What are the 4 different ways that a protozoa can undergo fission (what are the 4 types of fission)?

A
  1. Spherical fission
  2. Longitudinal fission
  3. Transverse fission
  4. Oblique fission
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15
Q

What occurs in sexual reproduction of protozoa?

A

Fusion of gametes or gametocytes to produce zygotes

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16
Q

What are the 5 stages of reproduction for malaria?

A
  1. Asexual phase (human is infected)
  2. Exoerythrocytic phase (in liver cells)
  3. Erythrocytic phase (in RBC)
  4. Gametocyte phase (in RBC)
  5. Sexual phase (in mosquito)
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17
Q

What is an example of a protozoan disease that involves mosquitos?

A

Malaria

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18
Q

What is the mode of transmission of malaria?

A

Female mosquitoes (Anopheles)

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19
Q

What are the s/s of malaria?

A

Fever, chills, sweats, cough, diarrhea, respiratory distress, headache, shock, renal and liver failure, pulmonary and cerebral edema, come and death

20
Q

What are the three leading causes of infection-related deaths seen worldwide?

A
  1. AIDs
  2. Tuberculosis
  3. Malaria
21
Q

Approximately how many deaths are associated with malaria each year?

A

Half a million

22
Q

What are some control strategies for preventing the spread of malaria?

A
  • prevent mosquito bites (netting or repellents)
  • prevent entry (close doors/windows, have screens)
  • prevent mosquito breeding (avoid water logging; kill larvae)
23
Q

What is used to kill the asexual forms of malaria? the sexual forms?

A

Asexual = Chloroquine
Sexual = Primaquine
- these two things are used in the treatment of malaria

24
Q

What is the protozoan disease that is acquired through the ingestion of water contaminated with fecal matter containing cysts?

A

Giardiasis (Beaver fever)

25
Q

What are the s/s of Giardiasis?

A

Chronic diarrhea, abdominal cramps, bloating, frequent loose and pale greasy stools, fatigue, weight loss

26
Q

What is the treatment for Giardiasis?

A

Usually self-limited

- rehydration therapy and antibiotics (metronidazole)

27
Q

What happens during the intestinal phase of Giardiasis?

A

Excystation occurs in the small intestine

  • two trophozoites are released from each cyst
  • multiply by longitudinal fission
28
Q

Which protozoan disease has thick and thin walled oocysts?

A

Cryptosporidiosis

29
Q

What is the main reservoir for Cryptosporidiosis?

A
  • Humans
  • Cattle
  • Other domestic animals
30
Q

How does self-infection occur with crytposporidiosis?

A

Commonly by thin-walled oocysts

31
Q

True or False:

Thick-walled oocysts of cryptosporidiosis can survive in the environment

A

True

32
Q

What are the s/s of Cryptosporidiosis?

A

Profuse and water diarrhea + abdominal cramps

- sometimes malaise, fever, anorexia, and vomiting

33
Q

True or False:

10-20% of AIDs patients suffer cyrptosporidiosis at some time during their illnessq

A

True

34
Q

What is the treatment for cryptosporidiosis?

A

Usually self-limited

- rehydration therapy, and antibiotics (azithromycin)

35
Q

True or False:
Thick walled oocysts of cryptosporidium allow for survival in the host. Thin walled oocysts of cryptosporidium allow for survival in the environment

A

False

  • Thick walled = environment
  • Thin walled = host (auto-infection)
36
Q

What protozoan disease can be caused by cats?

A

Toxoplasmosis

37
Q

What is the mode of transmission for toxoplasmosis?

A

Ingestion of oocysts from the fecal droppings of cats

fecal-to-hand-to-mouth

38
Q

What is another mode of transmission for toxoplasmosis?

A

Ingestion of contaminated water or undercooked/raw meat

39
Q

What can happen if a pregnant women gets infected with toxoplasmosis?

A

Can cause miscarriage and/or serious physical and developmental damage to the fetus/newborn

40
Q

What are the s/s of toxoplasmosis?

A

Fever, lymphadenopathy, cerebritis, pneumonia, myocarditis, and/or death in the immunocompromised

41
Q

True or False:

The damage caused by congential toxoplasmosis is reversible

A

False

- causes birth defects (and death) due to irreversible damage to liver, brain, and spleen

42
Q

What protozoan disease does not produce any cyst or oocyst?

A

Trichomoniasis

43
Q

What is a protozoan disease that is a common sexually transmitted disease?

A

Trichomoniasis

44
Q

True or False:

Trichomoniasis can coexist with gonorrhea

A

True

- up to 40% in some cases

45
Q

What are the s/s of trichomoniasis in women?

A
  • small, pinpoint, non-raised, round, red strawberry-like rash
  • thin, foamy greenish-yellow discharge w/foul odor
  • cervical inflammation
46
Q

What is the treatment for trichomoniasis?

A

Metronidazole