Biology Questions and Answers
seeds. They comprise the bryophytes
and the pteridophytes.
Phanerogamic plants are those having
seeds. They comprise and the angiosperms.the gymnosperms
- What are the two divisions
of the angiosperms?
The angiosperms armonocotyledonous and dicotylee divided intodonous. (^)
(These categothis text.) ries are explained later in
- What are the three basic
sexual life cycles studied in
Biology? Which of them
corresponds to metagenesis?
Which of them is the human
life cycle?
Sexual reproduction may take place
through three different typcycles: the haplontic (the being ises of life
haploid) haplobiontic (a single type of
being) cycle; thhaploid) haplobiontic (a single e diplontic (the being istype of
being) cycle; and the diplobiontic cycle
(two types othe other diploid). The diblobiontic cyclef beings, one haploid and (^)
is known as alternation of generations,
or metagdiplontic haplobiotic (a single diploidenesis. In humans the cycle is
being).
- What respectively are
zygotic meiosis, gametic
meiosis and sporic meiosis?
Zygotic meiosis is the one that occurs ithe haplontic haplobiontic life cycle. n
Gametes funite forming the diploid zygote. Therom adult haploid individuals
zygote undergoes meiosis and
generates fmitosis develop into adult individuals.our haploid cells that by (^)
Therefore in the zygotic meiosis the cell
that undergoes mand the gametes areiosis is the zygotee formed by mitosis.
Gameticproduces g meiosis isametes, i. that in which meie., haploid cellsosis
that each of which another gamete forming the zygote. Itcan unite with (^)
occurs in the diplontic haplobiontic life
cycle (individual e.g., in humans) iis diploid and meiosis formsn which the (^)
gametes.
Sporic meiosis(alternation of generations, or happens in metagenesis
diplobionticcells from the diploid individ life cycle). In this life cycleual (called
sporophyte) undergo meiosis producing
haploid others but insteaspores that do not unite withd develop by mitosis (^)
into haploid individuals (called
gametophytes). Igametes are made by mitosisn this life cycle th from cellse (^)
of the gametophyte.
- Are gametes always made
by meiosis?
In the plant lifcycle) and in the haplontice cycle (diplobiontic life haplobiontic (^)
life cycle gametes are made by mitosis
and not by meiosis. Obviously in some
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