9.28 Gametogenesis Flashcards Preview

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Flashcards in 9.28 Gametogenesis Deck (19):
1

in meiotic division, the cells go from 2n to ___, then after the first cell division is is ___, and after the second, it goes to ___

4n (92 chromosomes)
2n (46 chromosomes)
1n (23 chromosomes)

2

in the follicle, an oocyte is surrounded by __________ cells, which secrete _______ that become the zona pellucida

granulosa
glycoproteins

3

what is the zona pellucida? why is it important?

it is a jelly-like coat around the oocyte, which is a central docking region for sperm

4

in oogenesis, one precursor cell gives rise to _____ ovum (egg) and 2 or 3 ____________

one
polar bodies

5

oocytes start primary meiosis before birth, primary meiosis is completed only upon ________. Now, the oocyte is __n and there is a _______ that is also __n

puberty
2n
polar body that is also 2n

6

During _______, the second meiosis occurs, and is only completed upon ________. Now, we have a __n oocyte.

ovulation
fertilization
1

7

in spermatogenesis, one germ cell gives rise to ____ sperm.

4

8

spermatogenesis takes place in _______________ of the testes. They start on the outside, mature, and get released into the _____. _____ cells help this process.

seminiferous tubules
lumber
sertoli

9

Down's syndrome is caused by:

an extra copy of chromosome 21.

10

The extra copy of chromosome 21 in Down's syndrome resulted from abnormal _______ division

meiotic

11

Patau's syndrome is also called __________. It is a copy in chromosome ___ and is usually not compatible with life.

trisomy 13
13

12

This disease occurs when a single X chromosome is inherited instead of 2.

Turner syndrome

13

what are some of the manifestations of Turner syndrome?

short stature, webbed neck, reduction in secondary female characteristics, sterile.

14

an extra copy of the X chromosome in males (XXY)

Klinefelter syndrome

15

what is the translocation between Ch13 and Ch14 called?

Robersonian translocation

16

in Robersonian translocation, what chromosomes are rearranged? They make a _______________ at the centrosome.

13 and 14
fused chromosome at their centrosome.

17

People with Robersonian translocations are usually _____ since it can cause uneven meiosis.

sterile

18

what are some main causes of male infertility?

absence of sperm, reduction in number, or production of defective sperm

19

what are main causes of female infertility?

failure of oocyte maturation or release.
blockage of egg transport to fallopian tubes.