Directed Reading: Protists
Complete each statement by writing the correct term in the space provided.
1. Unicellular protists can reproduce asexually by binary fission, ______________________, or
______________________.
2. Unicellular protists are able to perform a wide variety of functions because their cytoplasm contains
______________________.
3. Green algae contain chloroplasts, which enable them to produce energy by ______________________.
4. The classification of protists is likely to change as scientists study the organisms’
______________________, ______________________, and ______________________.
In the space provided, write the letter of the description that best matches each term.
5. _____ gamete
a. diploid cell that can survive harsh conditions
6. _____ zygospore
b. diploid cell
7. _____ Zygote
c. haploid cell
Read each question, and write your answer in the space provided.
8. Describe alternation of generations in general terms.
9. How is the zygospore of Chlamydomonas formed?
10. How do amoebas move around?
11. How do ciliates reproduce sexually?
In the space provided, write the name of the protist group that best matches the description.
12. ____________________ do not move; parasitic
13. ____________________ surround and engulf food particles; may have a test
14. ____________________ free-living; complex unicellular; covered with a flexible covering and short
structures
Complete each statement by underlining the correct term or phrase in the brackets.
15. The shells of diatoms are made of [silica / cellulose].
16. Euglenoids move toward light with the help of [cilia / an eyespot].
17. Diatoms tend to get [larger / smaller] with each generation.
18. During reproduction, the two shells of the diatom [separate / dissolve].
In the space provided, write the letter of the description that best matches each term.
19. _____ algae
20. _____ green algae
21. _____ red algae
22. _____ brown algae
a. multicellular; found in marine environments;
kelp
b. term used for protists that are phototrophs
c. most are freshwater unicellular organisms;
marine plankton; inhabit damp soil; plantlike
d. multicellular; found in warm ocean
environments; good at absorbing light that
penetrates deep waters
Complete each statement by writing the correct term or phrase in the space provided.
23. During environmental stress, cellular slime molds form multicellular colonies and release
______________________.
24. A (n) ______________________ slime mold contains many nuclei, but they are not separated by cell
walls.
25. A(n) ______________________ ______________________ that attacked grape vines almost destroyed
the French wine industry in 1879.
Read each question, and write your answer in the space provided.
26. How does Paramecium get food?
27. What are some of the characteristics of Paramecium caudatum?
In the space provided, write the letter of the description that best matches the term or phrase.
28. _____ plantlike protists
a. ingest food
29. _____ fungus-like protists
b. photosynthetic
30. _____ animal-like protists
c. absorb food
Read each question, and write your answer in the space provided.
31. Which protist causes giardiasis? How is the disease transmitted?
32. How do protists harm humans?
33. Describe the ways in which protists help humans.
34. What is an algal bloom? How can it cause harm?
Study the following steps in the life cycle of the protist that causes malaria.
35. Determine the order in which the steps take place. Write the number of each step in the space
provided.
_____ An infected mosquito bites a human to get blood and injects saliva, which contains sporozoites.
_____ As red blood cells die, anemia develops.
_____ After 48 hours, the merozoites burst from the red blood cell, killing it.
_____ The merozoites infect red blood cells and divide rapidly.
_____ The sporozoites produce merozoites.
_____ The new merozoites invade and destroy more red blood cells.
_____ The sporozoites infect the liver, where they divide rapidly.
36. Label the type of locomotion in the organisms above. (underneath)
1. Giardia; The organism forms cysts, which are eliminated from the body in feces. The disease is passed to a new host through water
that is contaminated with feces containing cysts.
2. Protists cause a number of diseases in humans and livestock.
3. Protists live in the digestive tracts of humans and animals that humans eat, and they aid in digestion. Protists produce much of
Earth’s oxygen, take up carbon dioxide, and make up much of the plankton in the ocean. Many protists help recycle important
chemicals, such as nitrogen and carbon. Other protists are involved in the manufacture of food products.
4. An algal bloom is a rapid increase in algal growth in a aquatic ecosystem. It causes harm to humans when the organisms produce
large amounts of toxins, which get into food chains. When an algal bloom dies, the bacteria that decompose the algae consume large
amounts of oxygen, which harm the ecosystem by killing fish and other marine animals.
5. 1 6. 7 7. 5 8. 4 9. 3 10. 6 11. 2
SECTION: PROTISTS AND HUMANS
1. Amoebas use extensions of their cells, called pseudopodia, for locomotion.
2. Two cells join and exchange one of their micronuclei with each other in a process called conjugation.
3. Sporozoan 4. amoeboid protist 5. ciliate
6. silica
7. an eyespot
8. smaller
9. separate
10. b 11. c
12. D 13. a 14. spores 15. plasmodial
16. downy mildew
17. Cilia in the oral cavity beat and sweep food particles into the cell. The food is engulfed in a food vacuole, where enzymes digest it.
18. tough but flexible outer covering, thousands of cilia, a macronucleus, a micronucleus, contractile vacuoles, and an oral groove
19. B 20. c 21. a
SECTION: GROUPS OF PROTISTS
1. budding, fragmentation
2. organelles
3. photosynthesis
4. DNA, RNA, proteins (in any order)
5. c
6. a
7. b
8. In alternation of generation, a sexual generation that produces gametes alternates with an asexual generation that produces
spores.
9. During sexual reproduction, haploid cells divide by mitosis to produce haploid gametes. Two haploid gametes fuse to form a
diploid zygote, which develops a thick protective wall and becomes a zygospore.
SECTION: CHARACTERISTICS OF PROTISTS