a. Why are sperm
small and mobile and why are eggs large and immobile?
Sperm is small and mobile since of the role it plays in
fertilization (Alberts et al. 2002).
The sperm has to be quick and mobile in order for it to
fertilize an egg (Alberts et al.
2002). Sperm are not easily destroyed and they are closed from the environment,
they can live in the womb for about 3 to 5 days (Gelder n.d.). In comparison, the egg cell is the largest human
cell that measures from 0.15 to 0.2 mm (Gelder n.d). The egg is immobile since it
can be destroyed easily, a change in environment could be fatal to the egg (Gelder n.d).
b. Why do males
produce so many sperm, and females produce so few eggs?
Females produce so few eggs since Oogenesis, the formation
of ova occurs before a female is born (textbook). Cells develop during embryonic
development then the cells divide by the process of mitosis leading a female to
be born with about 1 to 2 million primary oocytes. These primary oocytes are stopped
in prophase 1 of meiosis (textbook). In comparison, in male’s spermatogenesis
begins in the seminiferous tubules located in the testis (Chocu et al. 2012). The process is divided
into three phases, the mitotic phase, the meiotic phase and the spermatogonia
pahse (Chocu et al. 2012). In the
first phase germ cells undertake a sequence of mitoic divisions (Chocu et al. 2012). To continue, in the second
phase the two divisions produce the haploid spermatids which leads to the third
phase in which spermatids separate into spermatozoa (Chocu et al. 2012). Males need over 20-40 million sperm in an ejaculation
in order for a sperm to reach and penetrate the ovum, if a male has less than
they are barren (). In comparison, a female only needs 1 ovum in which a sperm
can reach in order to
c. What are the
functions of the various parts of the sperm (tail, mitochondria, head,
The head of the sperm is
oval-shaped and the size ranges from5 to 8 um. The Acrosome is an organelle
that contains up to 40 to 70% of sperm head area (Sandra 2017). To continue, the
function of the acrosome is to climate the outer layer of the egg cell in order
to allow sperm to enter (Sandra 2017). The mitochondria of the sperm are
located in the middle of the sperm (Sandra 2017). The function of the mitochondria
is to provide energy that is needed in order for the flagellum to swim to meet
the egg cell (Sandra 2017). The function of the tail is for the mobility of the
sperm, the tail is also known as the flagellum (Sandra 2017). In addition, the
length of the tail ranges to be about 50 um (Sandra 2017).
d. What are the roles
of the follicle cells in the egg, and of the relatively large amount of
cytoplasm in the egg?
Primary follicles arise when the first follicle is
stimulated, when the oocyte expands follicular cells then divide (Paxton 1970).
A primary follicle is when there are two layers of follicular cells on a
1970). The cells form layers
surrounding the oocyte and the become known as granulosa cells that will secrete
progesterone after ovulatory occurs (Paxton 1970). The primary follicle then arises into a
secondary follicle, the only difference being larger follicular cells and follicular
1970). The follicular fluid is nutritive fluid for the oocyte (Paxton 1970).
The secondary follicle then arises into a Graffian follicle (Paxton 1970).
When this occurs the first meiotic division is complete and the oocyte is now a
secondary oocyte that can being its second meiotic division. (Paxton 1970).