Biology of Plants
Spring 1997

Exam III

Name_______________________
Use any "fungus" as an example to diagram a life cycle. Be sure to include by sketch and label all of the various stages of its life history. You may not use yeast as the example. (25 points total)

name + 3x each of:

If your life cycle above is missing any parts of the sporic life cycle, explain here what exactly is missing or subject to interpretation.


Of all the ascomycete fungi, one is extremely simple. It is yeast. It is completely unicellular, never filamentous. Both vegetative diploid yeast cells and vegetative haploid yeast cells can reproduce by mitosis with cytokinesis demonstrated as "budding." Yeasts are isogamous and syngamy is instantaneously complete. Using this information, sketch and label the life cycle of yeast below: (16 points total)

2x each of:

If someone were to call this yeast life cycle "gametic", what else would it have to be? Explain. (4 points total)

zygotic because the zygote becomes the sporocyte

If someone were instead to call this yeast life cycle "sporic", what would constitute the gametophyte and the sporophyte? (4 points total)

the populations of budding haploid and diploid cells, respectively

(The following fill-ins are worth 8 points total)
If syngamy were a long, drawn out process...
...name the first step.plasmogamy
...what would be the second (last) step?karyogamy
...what would the cells be called before the first step?haploid, gametes
...what would the cells be called between the two steps?dikaryotic, heterokaryotic
...what would the cells be called after the second step?zygote, diploid
What is the nuclear condition (haploid, diploid, etc.)...
... in a basidiospore?haploid
...in a basidium just before basidiospore formation?diploid
...in the stipe (stalk) of a basidiocarp (mushroom)?dikaryotic


In the algae you were introduced to various gamete mating types. Name and describe the three fundamental kinds of gametes and give an example alga for each type. (12 points total)
Gamete TypeDescription (2 pts each)Example Alga
iso-gamousboth gametes motile and same sizeChlamydomonas, Cladophora
aniso-gamousboth gametes motile, one larger and the other smaller(none given...freebie)
oo-gamousone gamete small and motile (sperm), the other large and sessile (egg)Fucus, Oedogonium

In algae you have been introduced to three types of life cycle. Name each one, completing the description, and give an example alga for each type. (10 points total)
Life Cycle TypeDescriptionExample Alga
spor-icThere is both a gametophyte and a sporophyte because both the spores and the zygote divide by mitosis.Cladophora, Polysiphonia
gamet-icThere is a sporophyte but no gametophyte because the
sporebecomes the
gamete.
Fucus
zygot-icThere is a gametophyte but no sporophyte because the
zygote becomes the
sporocyte.
Oedogonium

In addition to many examples of algae, you have seen them grouped into divisions. Describe how you would determine the division of a mystery alga given to you. Maybe a "key" is a good way to organize your response. (28 points total)

If pigments include blue or red phycobilin pigments:

if cells lack nucleus and chloroplasts: blue-green algae (Cyanophyta)
if cells have nucleus and chloroplasts: red algae (Rhodophyta)

If pigments include chlorophyll c:

if unicellular with cellulosic plates: dinoflagellates (Pyrrophyta)
if wall contains silicon: diatoms (Chrysophyta)
if multicellular: brown algae (Phaeophyta)

If pigments include chlorophyll a and b:

if wall is cellulose: green algae (Chlorophyta)
if cell has internal pellicle instead of wall: euglenoids (Euglenophyta)


(The following fill-ins are worth 7 points total)

Thinking of vascularization in bryophytes, the equivalent of:

...xylem is hydroid

...phloem is leptoid

The oogonium found in algae has evolved into the bryophyte's: archegonium

which means that it has this new feature: sterile jacket

The antheridium found in algae has evolved into the bryophyte's: antheridium

which means that it has this new feature: sterile jacket

The life cycle of all true plants (bryophytes and vascular plants)

is: (circle)       gametic       sporic       zygotic

In as few words as possible describe a bryophyte gametophyte (list the parts). (4 points total)

thallus, rhizoid, antheridium, archegonium

(These gametophyte questions are worth 3 points total)
Among bryophytes, which has
the most advanced gametophyte? (circle)       hornworts       liverworts       mosses

What features of the gametophyte led you to your decision above?
presence of "vascular" tissues

In as few words as possible describe a bryophyte sporophyte (list the parts). (3 points total)

foot, stalk, sporangium

(These sporophyte questions are worth 3 points total)
Among bryophytes, which has
the most advanced sporophyte? (circle)       hornworts       liverworts       mosses

What features of the sporophyte led you to your decision above?
meristematic (indeterminate) growth, photosynthesis, stomata

In the space below, tell why bryophytes are relatively short in stature (why do we not have bryophyte "trees"?). (2 points total)

bryophytes lack lignin which means they cannot support a large plant body

their vascular tissue is too limited to permit large body size

In the remaining space, describe the feature of the cells of a bryophyte that made life on land possible (why can bryophytes withstand life in air while most algae cannot). (2 points total)

cutinization of surface cells and especially spores help avoid desiccation

the gametangia and sporangia have sterile jackets to help avoid desiccation


In Marchantia (a liverwort): (4 points total)
The location of chimney cell and pore formation is determined by:light       gravity
The location of rhizoid formation is determined by:light       gravity
The growth of rhizoids is inhibited by:light       gravity
The growth of the thallus orients the chimney cells and pores toward:light       gravity

The remainder of this page is blank. Sketch out and label the life cycle of any lower vascular plant showing all -phytes, -angia, their contents, and products. Feel free to rotate the page if needed. (35 points total)

name + 3 points each for:


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