Protazoa Flashcards
What are the main characteristics of Protozoa
65,000 species!
Most are non-pathogenic
Free-living organisms
Complex life cycles
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Most are unicellular, colonies are rare
Locomotive structures - flagella, cilia, or pseudopods
Variety of shapes
Typically inhabit water or soil
What is the trophozite stage of the Protozoa life cycle
Motile feeding stage
What is the cyst stage of the Protozoa life cycle
A dormant resting stage
Describe the Protozoa life cycle
Trophozoite/ feeding stage
- drying due to lack of nutrients
Early cyst wall forms
Forms into a mature cyst (dormant stage)
-> moisture and nutrients restored
Cyst wall breaks open
Trophozoite is reactivated
What are the 3 main locomotive structures
Flagella, cilia, pseudopodia
What types of Protozoa have pseudopods
Amoeba and radiolarian
What are pseudopods
Temporary cell extension used for movement
- cell membrane pushes in one direction
- cytoplasm flows into bulge
- allows the protozoan to move and drag the rest of the cell behind it
What are radiolarian
0.1 - 0.2 mm diameter
- silica based skeletons
Found in oceans as part of zooplankton
- non-motile
- solitary or colonial
What are features of cilliated Protozoa
Non pathogenic
- contain 2 nuclei ( one for everyday functions one for reproduction
What is the difference between the power stroke and the recovery stroke
Power is for movement the record is the movement of re setting the flagella
What are apicomplexa
All are parasitic
Example Toxoplasma gondii
Trophozoites move by gliding and flexion
Some trophozoites are non-motile
Complicated life cycles – lots of stages and
hosts
Produce sporozoites for transmission to new
host
Balantidium Coli
Intestinal protozoan parasite
• Transmitted faecal-oral route - contaminated food and
water
• Infection is mostly asymptomatic
• Immunocompromised people experience persistent
diarrhoea and abdominal pain
• More serious complication perforated colon
- occurs in humans and pigs
