Biology Questions and Answers
- Why is the cytoplasm of
sperm cells very reduced?
Why do mitochondria of sperm
cells concentrate in the base
of the flagellum?
The reduced cytoplasm ofdecreases the cell weight and provides a sperm cells (^)
more hydrodynamic shape for the
locomotion in fluids.
The high concentration of mitochondria
at the base of the flagellum osperm cell is necessary for the energeticf the (^)
supply of the flagellum (for it to beat
and move the sperm cell).
- Concerning events during
the periods of life how
different is the gametogenesis
in women and in men?
The formation of spermatogonia in men
takes pperiod. The formation lace during the embryonicof sperm cells (^)
however is a continuous process that
begins in puberty and goes on until olage and sometimes during all the d
remaining life of the man.
In women all oogonia are formed before
birth. The oogonia turthat enter the first division on into oocytes If meiosis (^)
(meiosis I). This division however is
interrupted at prophase only in puberty. After the beginning ofand continues (^)
menses an egg cell is released during
each period and, if fecundated, itfinishes the meiotic division. The
oogenesis stops after menopause
(cessation othe climactericf the menstrual activity) period of life begins. and
- Indicating the name and
respective ploidy of each
involved cell how can the
formation of egg cells from
germ cells be described?
The formation germ cell called oof egg cells begins with aogonium (2n) that
undergoes mitosis and gives birth to the
oocyte I (2n). The oocyte Imeiosis I that however is int undergoeserrupted at (^)
prophase. After puberty during each
menstrual cycle an meiosis I and generate one oocyte IIoocyte I finishes th (n)e (^)
and the first polar body (n). With
fecundation tundergoes mhe oocyte IIeiosis II and produces th then (^) e
mature egg cell (n) and the second
polar body (n).
- What is the first polar
body? How different is it from
the oocyte II?
In oogenesis the oogoniumdifferentiates into oocyte I (2n) and this (^)
cell enters meiosis. After finishing the
first moocyte I forms two eiotic division (meiosis I)cells: the oocyte I the (^) I
(n) and the first polar body. The oocyte
II is bigger because it gthe cytoplasm and the cytoplasmicets almost all
structures of the oocyte I as a strategy
for metabolite aoocyte II cell goes then to the secondnd nutrient storage. The
meiotic division. The first polar body is
very smallit disintegrates or and almoststays attached lacks cytoplasm;to the (^)
oocyte II.
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