Download Practice Questions MT I Oct 03, 2011

Practice Question for Mid-term I
Which of the following is not a characteristic of prokaryotes?
a) Spend most of their time in the diploid state
b) a nuclear region containing genetic material
c) very small cells with permeable membranes well adapted for feeding on dissolved
material
d) possess the broadest range of biochemical capabilities in the living world
e) can disperse either through resistant spores or as highly motile “swarmers”
In a Winogradsky column methane would be expected to be most abundant at
a) the bottom, farthest from the air, where hydrogen would be the most abundant
b) in the middle of the column where traces of O2, will be present
c) in the lower portion of the column, where no O2 is present but other electron acceptors
(nitrate and sulphate) are
d) methane would not likely be found in such a column
e) methane would be present throughout the column
In a Winogradsky column where would you most likely find sulfate reducing bacteria
a) the bottom where conditions are most reducing and sulfide is the most abundant
b) in the middle of the column where traces of O2, will be present
c) in the lower portion of the column, where no O2 is present but other electron acceptors
such as sulfate are
d) throughout the anerobic portion of the column, but only if light is present
e) anywhere in the column where there is organic matter for these heterotrophs to feed on.
In a Winogradsky column where would you expect to find Thiobacillus
a) at the bottom where conditions are most reducing and sulfide is the most abundant
b) in the middle where reduced sulfur compounds will be present and a slight amount of O2
will be found as well
c) in the lower portion of the column, where no O2 is present but other electron acceptors
such as sulfate are present
d) throughout the anerobic portion of the column, but only if light is present
e) throughout the aerobic portion of the column
Thiobacillus causes severe pollution problems with poorly disposed mine tailings
a) because they utilize organic matter as their energy source and release toxic waste
products
b) because they convert ferric iron to ferrous which is highly toxic
c) they oxidize iron pyrites to ferric iron and sulfate releasing a large amount of H+ into
streams and rivers
d) because they convert ferric to ferrous iron which is highly toxic
e) because they use up all of the carbon dioxide in the water
In which environments would you expect to find Methanogens
a) they are Archaea so they are not abundant in the modern world
b) in anoxic wetlands, or deep in the mud of lakes and ponds
c) in the guts of animals
d) b and c are both true
e) a and b are both true
Sulfate reducing bacteria can be of considerable use in bioremediation because
a) have metal reductases which can precipitate out uranium from water
b) can be used to treat sewage because they can remove nutrients
c) can remove H+ ions from acidified water
d) they are capable of methylating inorganic mercury
e) both a and c are true.
Where would you expect to find Thiocapsa
a) in oxygen rich waters where there is little dissolved organic matter
b) near the bottom in lakes and ponds where there is little or no oxygen and sulfide is
present
c) at depths where some light is present
d) both b and c are true
e) none of these are true
Halobacterium are considered photoheterotrophs because
a) they require light to fix CO2 into organic matter
b) they emit bioluminescence using ATP from heterotrophic activity
c) they use light energy trapped by bacteriorhodopsin, and stored as ATP to build their
biomass from simple organic molecules
d) they produce bacteriorhodopsin a pigment that absorbs light
e) none of these are true
In examining a green ball a few mm across attached to an aquatic macrophyte, you find that it
contains an array of short tapered filaments with small anucleate cells, some heterocysts, and
some oblong akinetes. You have likely found
a) Nostoc
b) Aphanizomenon
c) Microcystis
d) Rivularia
e) Cladophora
In examining green cells found in cavities growing within Azolla leaves, you find them to be
small, circular cells arranged in filaments with heterocysts. You have likely found
a) Anabaena
b) Microcystis
c) Rivularia
d) Oscillatoria
e) None of these
In examining green material growing on rocks downstream from the sewage plant effluent you
find find greenish filaments with anucleate cells shorter than wide growing within a thin
gelatinous sheath, with no filaments or akinetes. You have likely found
a) Oscillatoria
b) Lyngbya
c) Cladophora
d) Microcystis
e) None of these
In a plankton sample you find a bloom of small greenish cells, with no chloroplasts growing
separately within a gelatinous matrix, with no heterocysts or akinetes. You have likely found
a) Oscillatoria
b) Lyngbya
c) Aphanizomenon
d) Microcystis
e) Chlorella
In a plankton sample you find a bloom of filamentous dark anucleaute greenish cells, arranged in
irregular sheets. The filaments contain some heterocysts. You have likely found
a) Oscillatoria
b) Melosira
c) Aphanizomenon
d) Ulva
e) None of these
Cyanobacteria
a) are photoautotrophs
b) have no chloroplasts
c) are sometimes toxic and unpalatable to herbivores
d) grow well at warm summer temperatures
e) all of these are true
Species that undergo meiosis
a) produce gametes that are individually unique
b) are diploid for at least a part of their life cycle
c) produce spores during some stage of their life cycle
d) consist of an array of genetic clones
e) both a and b are true
Species that undergo zygotic meiosis
a) do not undergo mitosis in the diploid state
b) increase their numbers asexually by producing haploid spores
c) produce diploid spores
d) generally have a quiescent zygote
e) a, b, and d are all true
A lineage that undergoes zygotic meiosis can mutate to a sporic biphasic life cycle in one step by
a)
b)
c)
d)
e)
undergoing meiosis in the zygote stage
dividing mitotically as a zygote to produce a functioning diploid organism
by eliminating the haploid stage from its life cycle
by producing gametes instead of spores at meiosis
none of these are true
A lineage that undergoes sporic meiosis can mutate in a single step to undergo gametic meiosis
by
a) undergoing meiosis in the diploid (sporophyte) stage
b) eliminating meiosis from its life cycle
c) by producing gametes instead of spores at meiosis
d) by producing both megaspore and microspores from its sporangia
e) this change cannot be accomplished in a single step
Meiosis enhances genetic variation among gametes because
a) chromosomes of maternal and paternal origin sort independently
b) crossing over produces recombinant chromosomes not present in either parent
c) natural selection favours increased diversity
d) meiosis leads directly to gamete production and fertilization is a random process
e) both a and b are true
Evolutionary biologists are puzzled about the origin and widespread distribution of sex in the
living world because
a) populations that are asexual generally have higher fecundity than sexual ones.
b) production of male organisms and gametes specifically for the purpose of genetic
recombination is a costly process.
c) Although most lineages of higher plants and animals are sexual, asexual strains have
apparently arisen spontaneously in most taxa and often seem to be quite successful, in
some cases persisting for millions of years.
d) there is no one striking advantage to sex that can clearly offset the apparent disadvantages
e) all of these are true.
Diploid cells have two copies of their genome, and this
a) allows for increased genetic redundancy would makes them less vulnerable to mutagens
b) permits them to combine with other cells and exchange genetic material
c) complete the cell cycle faster and thus multiply more rapidly
d) to accumulate more nitrogen and phosphorus in their cells to support growth
e) all of these are true
Algae that produce gametes that are designated + or – instead of male or female, are called
a) oogamous
b) anisogamous
c) isogamous
d) biphasic
e) none of the above
Filamentous green algae such like Oedogonium or Ulothrix have zygotic meiosis life cycles that
differ from Chlamydomonas in that
a) meiosis does not occur in the zygote, but is deferred to a later stage in the life cycle
b) they are oogamous, but Chlamydomonas is isogamous
c) asexual growth potential is divided between increasing filament length and zoospore
production which increases the number of filaments
d) both b and c are true
e) none of these are true
Life cycles involving conjugation are a special case of which type of life cycle
a) zygotic meiosis
b) sporic meiosis
c) gametic meiosis
d) none of these
In Oedogonium we can infer that the mating type/sex of a cell is not determined at the point
where it hatches from the zygote because
a) there is no sexual stage in the life cycle
b) antheridia and oogonia form next to each other on the same filament
c) the same filaments give rise to both gametes and zoospores
d) filaments are formed when zoospores settle, attach themselves are begin to divide
e) none of these
In isogamous algae the mating type designated as + is functionally the female because
a) the gamete of the + mating type is larger
b) the genetic material in the zygote chloroplast usually has originated in the + gamete
c) there is no way to tell which of the two is female because they are morphologically
identical
d) none of these are true
A widespread freshwater filamentous green alga that has a sporic meiosis (biphasic) life cycle is
a) Mougeotia
b) Stigeoclonium
c) Zygnema
d) Cladophora
e) Melosira
You collect some green algae attached to rocks along the shore of a large lake. The alga has
branched filaments, and the cells are large (nearly 0.5 mm) and contain a nucleus and many disclike chloroplasts. You have most likely found
a) Cladophora
b) Stigeoclonium
c) Zygnema
d) Oedogonium
e) Spirogyra
You collect some pondwater and find green spherical hollow colonies with daughter colonies
inside embedded in a gelatinous matrix. Each of the cells has a single U-shaped chloroplast and a
pair of flagellae. You have like found
a) Chlamydomonas
b) Volvox
c) Microcystis
d) Pediastrum
e) Hydrodictyon
You collect some pondwater and find cells composed of two mirror image halves with a
cellulose wall, a large green chloroplast, and a nearly centrally located nucleus. Some of these
cells are paired up with others and forming a conjugation vesicle. You have likely found
a) Scenedesmus
b) Ankistrodesmus
c) a desmid
d) Pediastrum
e) Cymbella
You collect some pale greenish filaments from some nearshore stones. The cells are rectangular
with many small discoid chloroplasts, a nucleus and a cellulose wall. You find that some of the
filaments are linked together with tube-like bridges, and the cells of both filaments are empty
with dark zygospores aligned between them. You have likely found
a) Spirogyra
b) Zygnema
c) Oedogonium
d) Ulothrix
e) Mougeotia
Diatoms do well in the plankton of large lakes during spring and fall because
a) the wind-mixed unstratified water column is nutrient rich
b) the well mixed watercolumn keeps these relatively dense cells from settling to the bottom
c) the high viscosity of cold water slows down the sinking speed of diatoms
d) diatoms can stand to live at low light levels
e) all of these are true
The chloroplasts of diatoms usually appear brown because
a) they have little chlorophyll in them
b) they contain a type of chlorophyll which is not green
c) they are rich in carotenoids which usually impart a brownish appearance
d) none of these are true
You collect a plankton sample from a large lake during springtime and find a many long
siliceous filaments composed of cylindrical cells in girdle view, that contain large brown
chloroplasts. You have likely found
a) Melosira
b)
c)
d)
e)
Lyngbya
Uroglena
Ceratium
Fragillaria
Although the mosses and pterophytes are quite dependent on water, the most plausible reason
why they haven’t done nearly as well in the aquatic environment as flowering plants is
a) the leaves and their stomata do not function effectively in water
b) flowers are required in order for fertilization to be completed in water
c) their rhizomes are not able to tolerate anoxic sediments
d) their spores are adapted to be released and transported by air, which limits them to very
shallow, marginal aquatic environments
e) they are much more primitive than flowering plants
The life cycle of mosses remains strongly dependent on water because
a) the leaves lack a waxy cuticle and stomatal control mechanism for minimizing water loss
b) their rhizomes and stems lack efficient conducting tissues to transport water
c) their spores are released into water and require water for dispersal
d) the male gametes are flagellated and require water in order to locate the archegonium
e) a, b and d are all true
The life cycles of pterophytes (ferns, horsetails, quillworts etc) remain somewhat dependent on
water because
a) the leaves lack a waxy cuticle and stomatal control mechanism for minimizing water
losss
b) they lack effective rooting and vascular tissue
c) their spores are released into water and require water for effective dispersal
d) the male gametes are flagellated and require at least a film of water to locate the
archegonium
e) a, b and d are all true
The green portion of a moss plant
a) is the haploid gametophyte and produces antheridia and archegonia
b) is the diploid sporophyte
c) provides nutritional support for the sporophyte
d) produces haploid spores
e) both a and c are true
The reproductive stems of horsetails
a) are haploid, whereas the vegetative stems are diploid
b) produce male and female gametes
c) are part of the sporophyte and have strobilae at their tips which produce haploid spores
d) produce both megaspores and microspores
e) are often found growing as submerged macrophytes
The aquatic fern, Azolla, is somewhat atypical compared to most ferns in that
a) it does not have sporangia
b) they grow on the water surface with their rhizomes suspended in the water, instead of
rooted in soil
c) it is heterosporous rather than homosporous like most ferns
d) b and c are both true
e) a and b are both true
Aquatic ferns of the genus Salvinia have become invasive pests in many parts of the world
because
a) they are polyploid (sterile) and are capable of rapid vegetative growth, because they do
not expend energy on spore production
b) spores are not really required by ferns for effective dispersal
c) human activities including boat travel, canals, barges etc, and attempts to eradicate them
probably all serve to spread these plants, which then grow rapidly once they gain access
to open habitat
d) their seeds are likely being dispersed by migratory waterfowl
e) all of these are likely true
f) a and c are likely true
The female gametophyte in a flowering plant
a) is a free living haploid organism produced from a germinating megaspore
b) has no independent existence, and is limited to an 8-celled entity inside the ovule of a
pistillate flower
c) grows downward within the pistil of a flower when a pollen grain germinates
d) is produced from a megaspore
e) both b and d are true
The pollen grain of a flowering plant is
a) homologous to the microspore in Azolla
b) produced on an anther
c) is a haploid spore produced from a microsporangium
d) usually dispersed by insects or wind
e) all of the above are true
Azolla and Isoetes are similar in that
a) they have heterosporous life cycles
b) they grow as small leaf clusters on the water surface that have trailing rhizomes
c) they are both flowering plants
d) they are both aquatic pterophytes
e) both a and d are true
Vallesnaria are similar to Azolla and Isoetes
a) in that they are all heterosporous
b) in that they have tiny flowers that are wind pollinated
c) in that they can sprout asexually from rhizomes or terminal buds
d) in that they produce separate male and female flowers
e) both a and c are true
Lemna is similar to Azolla and Salvinia in that
a) they are all heterosporous
b) that they rarely reproduce sexually
c) in that they are capable of asexual proliferation from fragments or terminal buds
d) in their growth form which is a cluster of leaves floating on the water surface with
rhizomes suspended from it
e) all of these are true
Myriophyllum exhibits several traits that are commonly seen in aquatic flowering plants
a) finely dissected leaves that maximize surface/volume ratio
b) relatively high shoot/rhizome ratio
c) tiny flowers that are wind pollinated
d) ability to proliferate vegetatively through fragmentation
e) all of these are true
Typha differs from most aquatic plants
a) in that their flowers are large, conspicuous and insect pollinated
b) in that they produce extensive rhizomes through which they can proliferate asexually
c) in that their leaves are generally not consumed by aquatic herbivores so their biomass
enters the food chain mostly after they die, decay and are consumed by detritivores
d) a and b are both true
e) b and c are both true
True or False
In Spirogyra all of the cells in the same filament are of the same mating type/sex
In isogamous algae the gamete designated as the + or – mating types are functionally
indistinguishable
The overall similarity of the Charophycean life cycle to that of plants is one of the reasons that
we consider them the likely ancestors of plants
In algae that undergo conjugative life cycles there are no flagellated spores or gametes
Although Volvox is colonial and Chlamydomonas is unicellular their sexual life cycles are
nearly identical except that Volvox is oogamous whereas Chlamydomonas is isogamous
The only flagellated diatom cells are the sperm of pennate diatoms
A culture of diatoms is growing asexually by mitotic divisions. These cells are all haploid.
Bryophytes and pterophytes, which retain some dependence on water for sexual reproduction,
have not done nearly as well in the aquatic environment as their more terrestrially adapted
descendents, the flowering plants.
The microspore of Isoetes is homologous to the pollen grain of Potamogeton
Fill in the Blanks
Diatoms that appear circular in _________ view are referred to as _________ diatoms
Many aquatic plants can spread rapidly, asexually, through ___________.
The anther in a flowering plant produces pollen grains from a structure homologous to the
_____________ Azolla or Isoetes
The life cycle of Azolla and Isoetes both have ______________ life cycles, which differs from
most ferns and horsetails which are __________________.
Explain in a few sentences
Explain why metal reductases could be useful to sulfate reducing bacteria
Explain why methanogens are of considerable interest to people who are trying to predict climate
change
Explain why sulfate reducing bacteria would not do well in the presence of oxygen
Explain why Thiocapsa are generally found in a layer close to the substrate but not often in the
mud or high in the water colum
Explain why it would not be possible for a lineage undergoing zygotic meiosis can mutate in a
single step to a gametic meiosis life cycle.
Explain how meiosis increases the variety of genetic combinations in a population
Explain how we can infer that the mating type/sex of the cells released from an Oedogonium
zygospore is not predetermined at the point of release.
Suggest a possible reason why many of the filamentous algae that undergo conjugation have a
slimy external surface that prevents epiphytes from attaching to them
Explain why root development in aquatic flowering plants is much less than that found in their
terrestrial counterparts.
Explain why it is advantageous to Sphagnum to produce leaves that resist decay when they are
dead, and contain spongy lacunae that absorb water.
Explain how eutrophication generally affects submerged macrophytes, and why plants like
Lemna, Azolla and Salvinia are not susceptible to these effects.
Explain why plants like Potamogeton amplifolius or P. praelongus produce better fish habitat
than plants like Myriophyllum and Elodea.
Explain why most aquatic plants have tiny inconspicuous flowers compared to their terrestrial
counterparts.