Gametogenesis in Male Review
Like in female, controlled by __
Need those two hormones, and testosterone to __
- anterior pituitary hormones, FSH and LH
- have gametogenesis
I.Sperm cell is __(2n) reproduces by mitosis
II.Enables male to do what?
I.At some point, in the life on a spermatogonia, it __--> __
I.In commitment, what has to happen as part of commitment is __
II. 2n (Chromosome number)/ 2n (DNA molecule)
- make many stem cells throughout life
- comits to becoming a gameteà
- primary spermatocyte
- replication of genetic material
Meiosis I: in male gametogenesis
- - primary spermatocyte (2n/4n)à
- - secondary spermatocyte (1n/ 2n)
Meiosis II in male gametogenesis
- Meiosis II:
- - four cells that are completely haploid (chromatids separate)à spermatids
- Spermatogenesis is from top up to the last four haploid cells that do not resemble sperm:
End of Meiosis II sperm
- round, nondistinct cellsThey have to be streamlined into sperm= spermiogenesis, where they obtain their sperm shape
One primary spermatocyteà makes what?
He always has __
- four sperm
- spermatogonia, primary stem cells
Gametogenesis in female
- Mature all at same time
- Meiosis and maturing at the same time
Difference in results for male and female
- end for female is larger and larger egg because she has to bring a dowry of structures that will be used by embryo in early development
- The sperm streamlines in gametogenesis in the male; gets smaller and only has cytoplasm
Female gametogenesis begins in what?
- Begins when she is in the womb (embryo)
- - in her ovary, all her stem cells commit to meiosis (oogoniaà primary oocytes)
When does each primary oocyte actually begin meiosis I?
- when she is still in the womb
- - by the time she’s born, they are rested in prophase I, meiosis I= all of them
What happens when she commits?
- She begins Meiosisà stops at prophase I at birth
- Every primary oocyte is an immature (primary) follicle
All commit to becoming __
If the commitment is the same, it has to __
- primary oocytes
- replicate its genetic material
Primary follicle is the ?
What happens at puberty?
, every month, one primary oocyte completes meiosis one
What determines where in cell cytokinesis will happen?
Where is the primary oocyte's nucleus?
Meiotic division in terms of location of nucleus?
- site of nucleus
- Primary oocyte’s nucleus is up top; meiotic division is horizontal
Contrast cytokinesis in male and female
uneven cytokinesis in female, not male
Result of meiosis I
Secondary oocyte and first polar body (1n/2n)
Function: of first polar body
- (terminal cell): remove a set of homologs from the developing egg
- Get rid of a set of chromosomes
Does the formation of just one ovum in female gametogenesis happen in all animals?
How do we know its only one egg?
- Doesn’t happen in all animals: some make four eggs
- We have one child at a time
- Other animals have litters
True or False:
Even though terminal cell, first polar body could go through meiosis IIà polar bodies
Meiosis II for females
- Secondary oocyte goes through meiosis II, producing one large cell; one small cell
- Small cell= second polar body
- Because of eccentric location of nucleusà result: large cell (ovum) and small cell (second polar body)
Both ovum and second polar body are __n/__n
Function of second polar body:
- reduce the set of sister chromatids from the (secondary oocyte)à what remains is the completely haploid egg (ovum)
- Get rid of remaining set to make the ovum completely haploid
End result in female of meiosis II
- egg is one full set of haploid chromosomes
- All polar bodies are 1n/1n
Where does the secondary oocyte come from?
What happens when the sperm enters the secondary oocyte?
- it enables the secondary oocyte to complete meiosis II
- The secondary oocyte is ovulated and enters the fallopian tube and meets the sperm there
True or False:
The stem cell in a female exists after birth.
false; does not
How do the secondary oocyte and sperm relate?
- Secondary oocyte= meiosis II if the sperm enters
- Needs sperm to complete meiosis II
- No spermà shed, not completed; it will never become an egg
First polar body and meiosis II relation
First polar body has no general function after it carries out it first; it generally doesn’t undergo meiosis II
Size of ovum in relation to starting cell
- Ovum is much larger than starting cell
- At end, when you have the mature ovum, it is much larger than the primary oocyte that began the process
- Part of the process of oogenesis is the accumulation of structures, so that it can foster early development
Why must the egg have so many structures?
- Embryonic genome does not turn out as quickly
- Has to rely on maternal messages, ribosomes, enzymes, etc.
Normal fertilization occurs in (be specific)=
ampulla of the fallopian tube
The following cells have similar genetic constitutions:
E. Both B and D