2. Gametogenesis

Question 1

What are gametes?

Answer 1

Haploid sex cells. (Eggs and sperm)

Question 2

What are the stages of gametogenesis?

Answer 2

1. The extraembryonic origin of the germ cells (primordial germ cells) and their migration to the gonads.
2. Increase in # of germ cells by mitosis.
3. A reduction in chromosomal # by meiosis.
4. Structural & functional maturation of the eggs and sperms.

Question 3

The first stage of gametogenesis is ………. In males and females. Whereas they differ in the…………?

Answer 3

In the first stage…(primordial germ cells & migration) they are identical. They differ in the last 3 stages, mitosis, meiosis, and the structure & function.

Question 4

In phase 1 of gametogenesis, the primordial germ cells migrate to?

Answer 4

The gonads.

Question 5

What are the carriers of genetic material?

Answer 5

Chromosomes

Question 6

Humans have approximately …… genes? And how many chromosomes?

Answer 6

35,000 genes and 46 chromosomes

Question 7

22 pairs of chromosomes are called? And how many pairs of sex chromosomes?

Answer 7

Autosomes.

1 pair of sex chromosomes

Question 8

One chromosomes of EACH pair is derived from?

Answer 8

A maternal gamete (oocyte) and a paternal gamete (sperm)

Question 9

T or F?

Each gamete contains haploid number of 23 chromosomes.

Answer 9

True.

Question 10

What happens to each chromosome before mitosis?

Answer 10

DNA replication

Question 11

What is a diploid progeny?

Answer 11

Each daughter cell receives the complete complement of 46 chromosomes. DIPLOID

Question 12

T of F? explain why?

The pattern of mitotic divisions differ from male and female germ cells.

Answer 12

True. For males, happens after puberty, for females, before birth ( 5 days after conception)

Question 13

What is the longest phase of mitosis?

Answer 13

Prophase ( where duplication and condensation happens)

Question 14

What is meiosis?

Answer 14

Cell division that takes place in germ cells to generate male and female gametes.

Question 15

T or F?

It requires 1 cell division to reduce the number of chromosomes to the haploid number of 23?

Answer 15

False. It requires 2 cell devision to produce 4 haploid daughter cells.

Question 16

Is the homologous pair of chromosomes in meiosis 1 haploid or diploid?

Answer 16

Haploid but they structurally haven’t separated yet.

Question 17

Meiosis 2 then separate sister chromatids, where each gamete contains 23 chromosomes.

Answer 17

:)

Question 18

What is a crossover?

Answer 18

Crossover are critical events in mitosis 1. It is the interchange of chromatid segments between paired homologous chromosomes.

Question 19

How is genetic variability enhanced?

Answer 19

Through random distribution and random crossover.

Question 20

What happens after meiosis for an oocyte?

Answer 20

1 primary oocyte gives rise to four daughter cells. Only one develops into a mature gamete and the other 3 are polar bodies. All are (22+ X)

Question 21

What happens after meiosis of a spermatocyte?

Answer 21

Gives 4 spermatids ( all are mature gametes ) 2 are 22 + X / 2 are 22+ Y

Question 22

of germ cells peak from the …… to the ……. Month of pregnancy?

Answer 22

Second to fifth month.

Question 23

What is atresia?

Answer 23

Is is where Numerous ooginia undergo programmed degeneration until menopause.

Question 24

T or F?

Spermatogonia maintain the ability to divide throughout postnatal life?

Answer 24

True.

Question 25

Atretic follicles are the highest during? - prepubertal - adult - post menopausal

Answer 25

Post menopausal

Question 26

Does the prepubertal phase have growing and ovulated follicles?

Answer 26

No.

Question 27

what phase has the most follicular pool?

Answer 27

Prepubertal

Question 28

What happens After oogonia undergoes mitotic divisions.

Answer 28

It is arranged in clusters surrounded by a layer of flat epithelium.

Question 29

Primary oocytes together with flat epithelial cells is called a?

Answer 29

A primordial follicle.

Question 30

At birth, all primary oocytes are arrested in…? And they enter ……….. stage until puberty

Answer 30

Prophase 1. Diplotene stage .

Question 31

Most oocytes become …………. During childhood (before puberty)

Answer 31

Atretic. (To die off)

Question 32

Secondary oocyte is arrested at……………….. until fertilization?

Answer 32

Metaphase 2

Question 33

Each month 15 to 20 follicles begin to mature and pass through 3 stages which are?

Answer 33

1. Primary ( preantral) 2. Secondary (antral) 3. Preovulatory (graafian follicle)

Question 34

The primary oocyte grows, Making the surrounding follicular cells to change from flat to?

Answer 34

Cuboidal to produce stratified epithelium of granulosa cells.