Chapter 28 Reading Quiz

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Chapter 28 Reading Quiz

1. Which kingdom is the most diverse of all
   eukaryotes?
2. In which kingdom do algae belong?
3. Through what process is it proposed that
   mitochondria chloroplasts came to reside within
   larger cells?
4. Plasmodium causes what (at this time) incurable
   disease?
5. The suffix -phyta refers to what main type of
   protist?

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1. List the characteristics of protists.

• They are the earliest eukaryotes ? showed up a
  billion years before the others
• Age ? 2.1 billion years
• There are 60,000 living species
• Exist as unicellular, colonial, and multicellular
• Aerobic, cilia flagella, asexual or sexual
• Bottom line a VERY diverse group ?

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2. Explain why some biologists prefer to use the
term undulipodia for eukaryotic flagella and
cilia.

• Because they appear to undulate or wave while
  acting like feet or podia ?

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3. Briefly summarize and compare the two major
models of eukaryotic origins, the autogenous
hypothesis and the endosymbiotic hypothesis.

• Specialization of the plasma membrane
  invagination
• ? gave rise to the nuclear envelope, the ER, the
  Golgi apparatus, etc
• Endosymbiotic associations may have resulted in
  organelles
• ? mitochondria, chloroplasts, etc ?

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Secondary endosymbiosis
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4. Provide three major lines of evidence for the
endosymbiotic hypothesis.

1. Similarities between organelles and prokaryotes
2. Molecular systematics lends support ? rRNA of
   chloroplasts is more similar in base sequence to
   RNA from certain eubacteria than rRNA in
   eukaryotic cytoplasm
3. 9 2 flagella and cilia are analogous to
   prokaryotes ?

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5. Explain why modern biologists recommend
expanding the original boundaries of the Kingdom
Protista.

• Observation that the Kingdom Protista is
  polyphyletic
• Current research groups protists into FIVE
  candidate Kingdoms ?

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6. Explain what is meant by the statement that
the Kingdom Protista is a polyphyletic group.

• Polyphyletic ancestry from several possible
  sources or directions
• Example
• Protists are ? animal-like
• plant-like
• fungus-like ?

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7. List five candidate kingdoms of protists and
describe a major feature of each.

1. Archaezoa ? lack mitochondria
2. Euglenozoa ? are both autotrophic and
   heterotrophic flagellates
3. Alveolata ? have subsurface cavities (alveoli)
4. Stramenopila ? diatoms, golden brown algae, and
   water molds
5. Rhodophyta ? red algae lack flagella ?

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8. Describe amoeboid movement.

• Amoebas move in a characteristic motion
• use pseudopodia ? form as cellular extensions
  and function in feeding and movement
• The cytoskeleton of microtubules and
  microfilaments functions in this amoeboid
  movement ?

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9. Outline the life cycle of Plasmodium.

• It is the protist that causes malaria
• The Anopheles mosquitos serve as the intermediate
  host and humans are the final host
• The Plasmodium spends most of its life in blood
  or liver cells ?

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10. Indicate the organism that causes African
sleeping sickness and explain how it spread and
why it is difficult to control.

• It is a species of Trypanosoma that causes the
  disease and are spread by the bite of the tsetse
  fly
• It belongs in the candidate Kingdom Euglenozoa,
  in the group Kinetoplastids ?

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11. Describe the function of contractile vacuoles
in freshwater climates.

• Contractile vacuoles allow freshwater protists
  to
• 1. Maintain water balance and homeostasis
• 2. Expel accumulated water from osmosis
• 3. Sometimes helps propel protists ?

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12. Distinguish between macronuclei and
micronuclei.

• Macronuclei ? large, over 50 copies of genome
• - controls everyday functions of the cell by
  synthesizing RNA
• - necessary for asexual reproduction during
  binary fission
• Micronuclei ? small, about 1 80 of these
• - no function in growth, maintenance, or asexual
  reproduction
• - functions only in conjugation (sexual genetic
  variation) ?

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13. Using diagrams, describe conjugation in
Paramecium caudatum.

• Page 559 in your book
• Two paramecium have diploid micronuclei which go
  through meiosis to create haploid micronuclei
• Through syngamy, the two paramecium exchange a
  couple haploid micronuclei, and these fuse to
  become a new, varied, diploid micronucleus
• The new diploid micronuclei may also then follow
  the cycle and exchange with another paramecium
  throughout its life cycle ?

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14. Explain how accessory pigments can be used to
classify algae and determine phylogenetic
relationships among divisions.

• Diatoms ? brown plastids cause brown/yellow color
• Golden algae ? yellow and brown carotenoids and
  xanthophyll
• Brown algae ? chlorophyll a, c and the carotenoid
  fucoxanthin
• Red algae ? chlorophyll a, carotenoids,
  phycobilins, and chlorophyll d
• - color is due to accessory pigment
  phycoerythrin ?

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• 15. In a chart, distinguish among the following
  algal groups based on their pigments, cell wall
  components, storage products, reproduction,
  number and position of flagella, and habitata.
  Dinoflagellata b. Bacillariophytac.
  Chrysophyta d. Phaeophyta

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16. Describe three possible evolutionary trends
that led to multicellularity in the Chlorophyta.

• Formation of colonies of individual cells
• ex Volvox
• Repeated division of nuclei with no cytoplasmic
  division (mitosis without cytokinesis
• ex Caulerpa
• Formation of true multicellular forms
• ex Ulva ?

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volvox
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caulerpa
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Life Cycle overview

• Sporophyte ? generally the adult form of an
  organism exists as a diploid (2n) makes spores
  (ex humans)
• Gametophyte ? generally an intermediate step
  before fertilization exists as a haploid (n)
  makes gametes (ex sperm eggs) ?

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17. Outline the life cycles of Chlamydomonas,
Ulva, and Laminaria and indicate whether the
stages are haploid or diploid.

• Chlamydomonas ? at maturity it is a single
  haploid cell
• - asexual at first, then sexual only if
  stressed, creating a diploid zygote
• 2. Ulva ? diploid sporophyte and haploid
  gametophyte
• 3. Laminaria ? sporophyte (2n) with sporangia
  makes zoospores (n) which make gametes (n) and
  then fertilization to get diploid sporophyte
  again ?

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18. Distinguish between isogamy and oogamy
sporophyte and gametophyte and isomorphic and
heteromorphic generations.

• Isogamy ? when gametes are morphologically
  indistinguishable
• Oogamy ? flagellated sperm fertilize the
  nonmotile egg
• Sporophyte ? 2n (diploid) generation
• Gametophyte ? n (haploid) generation
• Isomorphic ? gametophytes and sporophytes look
  alike
• Heteromorphic ? gametophytes and sporophytes are
  structurally different ?

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19. Compare the life cycles of plasmodial and
cellular slime molds and describe the major
differences between them.

• Plasmodial Slime Mold
• Multinucleated mass
• Diploid nuclei
• When stressed will form sexual reproductive
  structures called sporangia ?

• Cellular Slime Mold
• Solitary haploid cells
• Cells will aggregate when food supply is low
• Fruiting bodies (sporangia) function in asexual
  reproduction ?

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20. Provide evidence that the oomycetes are not
closely related to true fungi.

• Have coenocytic (multinucleated) hyphae
  (branching filaments) that are analogous to
  fungal hyphae
• Cell walls are made of cellulose rather than the
  chitin in true fungi
• Have biflagellated cells ? fungi lack flagellated
  cells ?

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21. Give examples of oomycetes and describe their
economic importance.

• Water molds ? grow on injured tissue but also
  will grow on the skin and gills of fish
• White rusts
• Downy mildews
• - both of these are parasitic on terrestrial
  plants act as pathogens ?

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22. Explain the most widely accepted hypothesis
for the evolution of multicellularity.

• Multicellularity arose from unicellular ancestors
  as colonies or loose aggregates of interconnected
  cells
• This involved cellular specialization and
  division of labor among the cells
• The End ?