Genetics 1.4 : Gamétogénèse

Question 1

Why do we say that méiose contribue à la gamétogenèse but it is not the whole story.

Answer 1

Meosis gets you as far as having the 4 spermatid cells (1n 1c). However, this is not the same thing as sperm cells. Maturation of these cells is a complete separate process. As such, meiosis is only a part of gametogenesis.

Question 2

What are Spermatocytes I?

Answer 2

They are Spermatogonies ayant subit une phase de croissance

1 spermatogonie donne ~ 200 spermatocytes I

2n

Question 3

True or False,

The passing from Spematocytes II -> Spermatides -> Spermatozoides is dependent on meiosis

Answer 3

Spermatocytes II -> spermatides yes
but maturation of spermatides to spermatozoides is not

Question 4

When does the second meiosis occur for oocytes?

Answer 4

Meiosis II is completed only if fertilization occurs,

Question 5

How do we go from primary ovocyte to secondary?

Answer 5

The growth of ovogonia into oocytes I occurs in the third month of prenatal development.

There are approximately 2.5 million of these cells at birth, but only about 400 of them will eventually mature (over the course of about 33 years).

These cells will remain in the prophase stage of meiosis I for decades (a stage known as Dictyotene).

The chosen oocyte I will quickly complete meiosis I, and one of the two cells produced by cell division becomes the oocyte II (ovum).

Question 6

Cellule formée à la fin de la méiose II suite à la fécondation de l’ovocyte II
par un spermatozoïde

Answer 6

Ovotide

Question 7

What is globule polaire. ROle and how many of them

Answer 7

They are the sad cells (ovocytes) that sacrifice themselves so that one ovocyte can survive and prosper

You would think we have 3 polar bodies. IN fact, there are only 2 since the first polar body resulting from meisosi 1 does not divide anymore. game over for that branch

The second polar body comes from the second division of the ovocyte II with the cytoplasm et al