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Sunday, 15 March 2015

FSc Notes Biology Part 1 Chapter 7 The Kingdom Protista or Protoctista

FSc Notes Biology Part 1 Chapter 7 The Kingdom Protista or Protoctista

Q 1. Write characteristics of protists.
Ans. The protists are unicellular, colonial or simple multicellular organisms that posses a eukaryotic cell organization. e.g., Algae, Protozoa.

Q 2. What are the major groups of eukaryotic organisms of kingdom protista?
Ans. The kingdom protista contain four major groups i.e.
  1. Single cell protozoans.
  2. Unicellular algae.
  3. Multicellular algae.
  4. Slime molds and Oomycotes.
Q 3. Who proposed kingdom protista?
Ans. John Hogg proposed kingdom protista for microscopic organisms.

Q 4. In which respects during course of evolutionary history, organisms in kingdom protists have evolved diversity?
  1. Size and structure.
  2. Means of locomotion.
  3. Ways of obtaining nutrients.
  4. Interactions with other organisms.
  5. Habitat.
  6. Modes of reproduction.
Q 5. Write two characteristics of protozoans.
Ans. Characteristics of Protozoans:
  1. All protozoans are unicellular.
  2. Most ingest their food by endocytosis.
Q 6. How zoo-flagellates obtain their food?
Ans. They obtain food either by ingesting living or dead organisms e.g., Euglena, Amoeba or by decomposing organic matter. e.g., Slime Algae.

Q 7. What is the habitat of zoo-flagellates?
Ans. Zooflagellates are free living, parasite, or symbionts.

Q 8. What is trypanosoma?
Ans. Trypanosoma is a human parasite causing African sleeping sickness. It is transmitted by the bite of infected tsetse fly.

Q 9. What is the habitat of choanoflagellates?
Ans. Choanoflagellates are sessile marine or freshwater flagellates which are attached by a stalk.

Q 10. Define pellicle.
Ans. Pellicle is a flexible outer covering of cilliates that gives them definite but changeable shape.

Q 11. In which way cillates differ from other protozoans.
Ans. Cilliates differ from other protozoans in having two kinds of nuclei large is meganucleus and small is micronucleus.

Q 12. From what tests of forminifera and of actinopods are made of?
Ans. Tests of forminifera all made of calcium where as those of actinopode are made of silica.

Q 13. Write two characteristics of Apicomplexans.
Ans. Characteristics of Apicomplexans:
  1. Apicomplexans are unicellular.
  2. They are non-motile.
Q 14. Write the name of apicomplexans that cause malaria.
Ans.  Plasmodium, the apicomplexans that cause malaria enters human body by the bite of infected female anopheles mosquito.

Q 15. What kind of body algae possessed?
Ans. The plant body of algae is thallus i.e., not differentiated into true roots, stems and leave and lack vascular bundles.

Q 16. Write two characteristics of dinoflagellates.
Ans. Characteristics of dinoflagellates:
  1. Most dinoflagellates are unicellular.
  2. Their cells are often covered with shells of interlocking cellulose plates impregnated with silicates.
Q 17. What stage is called plasmodium in slime molds?
Ans. The feeding stage of a slime mold is a multinucleate mass of cytoplasm that can grow to 30cm (1 foot) in diameter. This stage is called plasmodium.

Q 18. What are the similarities between fungus like protists and fungi?
Ans. Some protists resemble fungi in that they are not photosynthetic and some have bodies formed of thread like structure called hyphae.

Q 19. What causes late blight of potatoes?
Ans. Late blight of potatoes is caused by a water mold called phytopthora infestans.

Q 20. Why Euglena is placed in kingdom protists? 
Ans. They are placed in kingdom protista because they have chlorophyll and are photosynthetic but at the same time it had cell wall and is motile.

Q 21. What stage of material parasite causes chill and fever?
Ans. The simultaneous bursting of red blood cells cause the symptoms of malaria, chill, followed by high fever.

Q 22. What is conjugation?
Ans. Conjugation is a sexual process of cilliates during which two individuals come together and exchange genetic material.

Q 23. What is phylum of red algae?
Ans. The phylum of red algae is Rhodophyta.

Q 24. Name the pigments present in diatoms.
Ans. Chlorophyll a, chlorophyll c caroteins and fucoxanthin are pigments present in diatoms.

Q 25. What cause red tides?
Ans. Dinoflagellates are known to have occasional population explosions or blooms. These blooms color the water orange, red or brown and are called red tides.

Q 26. What are kelps?
Ans. The largest brown algae, which are tough and leathery in appearance. Whose leaf like structure called blade, stem like called stipes and root like structure called hold fast.

Q 27. Do slime moulds have definite cellular organization?
Ans. No, they do not have definite cellular organization.

Q 28. What is the causes of Irish potato?
Ans. Phytophthora is the cause of Irish potato.

Q 29. Do red algae has flagellated cells?
Ans. No, they does not have flagellated cells.

Q 30. What is the role of diatoms in ecosystem?
Ans. They are major producers in the aquatic ecosystem because of their extremely large numbers.

Q 31. What is common in Eukaryotic Red algae and Blue Green algae?
Ans. They do not have flagellated cells.

Q 32. What is sporangia?
Ans. During unfavorable condition, slime mold forms resistant haploid spore by meiosis with in stalked structure called sporangia.

Q 33. Write two characteristics of slime molds.
Ans. Characteristics of slime molds.
  1. The feeding stage of a slime mold is a multinucleate mass of cytoplasm.
  2. The plasmodium streams over damp, decaying logs and leaf litter. It often forms a network of channels that covers a large surface area.
Q 34. Write two differences between algae and plants.
Ans. Algae:
  1. Sex organs are unicellular.
  2. The parent body does not protect the zygote.
  1. A plant zygote grows into a multicellular embryo.
  2. Zygote is protected by parental tissue.
Q 35. Write two characteristics of Oomycotes.
Ans. Characteristics of Oomycotes.
  1. Their cell walls contain cellulose, not chitin.
  2. Their hyphae are aseptate (without cross walls).
Q 36. How are protists important to humans? What is their ecological importance?

Ans. Importance of Protists:

1. Disease:

  • The intestinal parasite, Entamoeba Histolytica that causes amoebic dysentery, germinates from resistant cysts with the digestive tracts of their mammalian hosts including humans.
  • Trypansoma is a human parasite causing African sleeping sickness. It is transmitted by the bite of infected tsetse fly.
  • Some Apicomplexans such as Plasmodium cause serious diseases such as malaria in humans.
  • Phytophthora Infestans have played infamous roles in human history as they were the cause of Irish potato famine of the 19th century. It causes a disease commonly known as late blight of potatoes. Because of several rainy, cool summers in Ireland in the 1840's, the water mold multiplied unchecked, causing potato tubers to rot in the fields. Since potatoes were the staple of Irish peasant's diet, many people (250,000 to more than 1 million) starved to death. The famine prompted a mass migration out of Ireland to such countries as the United States.

2. Chalk Formation:

  • Dead foraminiferans sink to the bottom of the oceans where their shells form a grey mud that is gradually transformed into chalk. Foraminiferans of the past have created vast limestone deposits.

3. As Food:

  • Some algae such as kelps are edible and may be used to overcome shortage of food in the world.
  • Larvae of some aquatic insects feed on aquatic protozoans. While these larvae are taken as food by clam, prawn and young fishes which are the ultimate source of food of man.

4. Useful Substances:

  • Marine algae are also source of many useful substance like algin, agar, carrageenan and antiseptics.

5. Produces:

  • Algae are major producers of the aquatic ecosystem, thus they play a basic role in food chains, providing food and oxygen to other organisms.
  • Ecologically, diatoms and dinoflagellates are the most important groups of producers in marine ecosystem.

6. Symbiotic Organism:

  • Trichonymophas are complex, specialized flagellates with many flagella which lives as symbionts in the guts of termites and help in the digestion of dry wood.

7. Helpful in the Study of Biological Processes:

  • The plasmodial slime mod Physarum Polycephalum is a model organisms that has been used to study many fundamental biological processes, such as growth and differentiation, cytoplasmic streaming, and the function of cytoskeleton.

8. Helpful in Sanitation:

  • Some protozoans play an important role in the sanitary betterment and improvement of the modern civilization in keeping water safe for drinking purpose. The protozoans living in polluted water feed upon waste organic substances and thus purify it. Some bacteria feed on the bacteria and purify the water indirectly.

9. Building Coral Reefs:

  • Some red algae incorporate calcium carbonate in their cell walls from the ocean and take part in building coral reefs along with coral animals.

Q 37. What are three major groups of protists?
Ans. Major groups of protists:
  • Protozoa                                        Animal-like protists.
  • Algae                                             Plant-like protists.
  • Slime molds and Oomycotes        Fungi-like protists.

Q 38. Give at least two examples of each group of protists.
Ans. Examples of groups of protists:
  • Protozoa:                                         Plasmodium, Amoeba.
  • Algae:                                              Euglena, Spirogyra.
  • Slime molds and Oomycotes          Phytophthora infestans, Physarum polycephalum.

Q 39. Green algae are considered ancestral organisms of green land plants. Discuss.
Ans. Due to the presence of starch and cellulose cell wall, it is generally accepted that plants arose from ancestral green algae. Evidence from RNA sequencing also indicates that green algae and the plants from a monophyletic lineage.

Q 40. What features distinguish Oomycotes from Fungi?
Ans. Features that distinguish Oomycotes from Fungi.
  1. They are regarded as more ancient group.
  2. Their cell walls contain cellulose, not chitin.

Written By: Asad Hussain