Biology – PROTISTS WORKSHEET
Wednesday April 10, 2013
Perry High School
Mr. Pomerantz_______________________________________________________________________________Page 1 of 3
Completion: Complete each statement.
1. Most protists live in a(n) ____________________ environment.
2. Some protists undergo sexual reproduction only at times of environmental ____________________.
3. One of the greatest effects that protists have on humans is that protists cause ____________________.
Short answer: Answer each question with two to three complete sentences.
4. In what three environments are protists found?
5. How do euglenoids illustrate the problems of classifying protists as plants or animals?
6. Why is the relationship between a termite and the protozoan Trichonympha an example of mutualism?
7. Describe how protists can impact the economy of a country without actually causing disease in humans.
Biology – PROTISTS WORKSHEET
Wednesday April 10, 2013
Perry High School
Mr. Pomerantz_______________________________________________________________________________Page 2 of 3
8. The diagram below is a generalized sexual life cycle of a protist.
Redraw this life cycle so that it illustrates the life cycle of the malaria parasite, Plasmodium. Indicate which cell
types and processes occur in the human host and which occur in the mosquito host. Also, indicate where asexual
reproduction occurs in this life cycle.
9. After a vacation in the tropics, you become seriously ill. Your symptoms include cycles of chills and fever every
48 hours. Why does your doctor suspect malaria?
10. Based on the diagram, describe how the malaria parasite reproduces and spreads from person to person.
Biology – PROTISTS WORKSHEET
Wednesday April 10, 2013
Perry High School
Mr. Pomerantz_______________________________________________________________________________Page 3 of 3
COMPLETION
1. ANS: water
2. ANS: stress
3. ANS: disease
ESSAY
4. ANS:
Protists are found in lakes and oceans; in damp soil, sand, and other moist environments, such as leaf litter; and
inside animals or plants.
5. ANS:
Some species of euglenoids are photosynthetic; others lack chloroplasts and are heterotrophic. Some
photosynthetic euglenoids may reduce the size of their chloroplasts and become heterotrophic if kept in a dark
environment.
6. ANS:
In a mutualistic relationship, both organisms benefit. The protozoan lives in the intestine of the termite, which
takes in wood that is digested with the aid of the protozoan. The termite cannot digest wood without the
protozoan, and the protozoan would not have a source of food without the termite.
7. ANS:
Protists can cause disease in livestock. The cost of treating the diseased livestock is passed on to consumers in the
form of higher prices.
8.
ANS:
9. ANS:
In the second stage of the cycle of Plasmodium, merozoites reenter the host’s bloodstream, invade red blood cells,
and divide rapidly. In about 48 hours, the blood cells rupture, releasing merozoites and toxic substances
throughout the host’s body and initiating a cycle of chills and fever. The cycle repeats itself every 48 hours as new
blood cells are infected.
10. ANS:
Female mosquitos acquire the malaria parasite Plasmodium when they bite infected humans. The mosquito then
bites another victim, injecting the parasites into the victim’s bloodstream. Once in the blood, the parasites travel
to the liver, where they reproduce. They then reenter the bloodstream, penetrate red blood cells, and reproduce
again. Every 48 to 72 hours, a new generation of parasites bursts out of infected red blood cells. This new
generation then invades other red blood cells.