Protozoa

Question 1

What are the characteristics of protozoa?

Answer 1

Belongs to Kingdom Protista 
Eukaryotic 
Unicellular 
Cell wall absent 
Heterotrophic 
Found in water-borne environment

Question 2

How are protozoa classified?

Answer 2

Mastigophora: use flagella for movement
Apicomplexan: do not have a specific mode of movement
Sarcodina: use pseudopodia for movement
Ciliophora: use cilia for movement

Question 3

How do protozoa reproduce?

Answer 3

Common way: asexual reproduction (by binary fission and schizogony)
Asexual division occurs in some forms
Both asexual and sexual reproduction can occur in apicomplexa
Only some protozoa undergo both asexual and sexual reproduction

Question 4

What are the different forms that protozoa exist in?

Answer 4

Cyst:
Dormant stage of protozoan
High infective and resistant to harsh conditions (ready for transmission)

Trophozoite:
Vegetative stage of the protozoan (growing and maintenance of the cell)
Proliferative; motile feeding stage

Question 5

What is the difference between bacteria, virus, fungi and protozoa?

Answer 5

Bacteria:
Ribosomes present 
Membrane-bound organelles absent 
Genetic material: DNA 
Cell wall present 

Virion:
Ribosomes absent 
Membrane-bound organelles absent 
Genetic material: DNA/RNA 
Cell wall absent 

Fungi:
Ribosomes present 
Membrane-bound organelles present 
Genetic material: DNA
Cell wall present 

Protozoa:
Ribosomes present 
Membrane-bound organelles present 
Genetic material: DNA 
Cell wall absent

Question 6

What are the roles of protozoan?

Answer 6

Decomposition; release of certain compounds
Regulate the number of bacteria in ecosystem
Part of the food chain
Transmit diseases to humans

Question 7

How to kill protozoa?

Answer 7

(Not kill) Filtration can filter all types of protozoa

Boiling can kill trophozoites and cyst form
Boil about 70 degree Celsius for 10 mins to kill cyst form