9.28 Gametogenesis Flashcards

1
Q

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

A

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

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2
Q

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

A

granulosa

glycoproteins

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3
Q

what is the zona pellucida? why is it important?

A

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

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4
Q

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

A

one

polar bodies

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5
Q

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

A

puberty
2n
polar body that is also 2n

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6
Q

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

A

ovulation
fertilization
1

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7
Q

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

A

4

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8
Q

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

A

seminiferous tubules
lumber
sertoli

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9
Q

Down’s syndrome is caused by:

A

an extra copy of chromosome 21.

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10
Q

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

A

meiotic

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11
Q

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

A

trisomy 13

13

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12
Q

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

A

Turner syndrome

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13
Q

what are some of the manifestations of Turner syndrome?

A

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

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14
Q

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

A

Klinefelter syndrome

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15
Q

what is the translocation between Ch13 and Ch14 called?

A

Robersonian translocation

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16
Q

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

A

13 and 14

fused chromosome at their centrosome.

17
Q

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

A

sterile

18
Q

what are some main causes of male infertility?

A

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

19
Q

what are main causes of female infertility?

A

failure of oocyte maturation or release.

blockage of egg transport to fallopian tubes.