Gametes

Question 1

What is an advantage of asexual reproduction?

Answer 1

Rapid

Question 2

What is a disadvantage of asexual reproduction.

Answer 2

Lack of diversity.

Question 3

Why is the female gamete 100 times larger than the male gamete?

Answer 3

It must contain substances to support oogenesis.

Question 4

When do primordial germ cells develop?

Answer 4

During embryonic development.

Question 5

When do germ cells undergo sex determination?

Answer 5

During embryonic development.

Question 6

The expression of which two genes indicates specialisation of a germ cell during specification and commitment stages of germ cell development?

Answer 6

Blimp 1 and Stella.

Question 7

What are the five stages of germ cell development?

Answer 7

Specification, commitment, migration, colonisation, sex determination.

Question 8

What are the two types of migration of germ cells?

Answer 8

Passive- as the embryo changes shape

Active

Question 9

What does the sex of germ cells depend on?

Answer 9

The environment of the gonads that they enter.

Question 10

At which phase does oogenesis arrest until puberty?

Answer 10

Prophase I of meiosis I.

Question 11

At what stages does spermatogenesis start (after pausing twice)?

Answer 11

Embryonic development, birth, puberty.

Question 12

When during embryonic development does migration of germ cells occur from the yolk sac to the embryo?

Answer 12

Week 4

Question 13

When during embryonic development does colonisation of the gonads by the germ cells occur?

Answer 13

Weeks 6-8

Question 14

When is testicular cancer likely to begin and when is it likely to manifest?

Answer 14

Begin: during embryonic development
Manifest: 20-30 years

Question 15

How are germ cells affected by testicular cancer?

Answer 15

They arrest their development and resist differentiation cues to remain as gonocytes.

Question 16

What are the support cells in male gonads?

Answer 16

Sertoli cells

Question 17

What are the support cells in female gonads?

Answer 17

Granulosa cells

Question 18

What are the major hormone producing cells in male gonads?

Answer 18

Leydig cells

Question 19

What are the major hormone producing cells in female gonads?

Answer 19

Theca cells

Question 20

What stage of meiosis produces primary spermatocytes/ oocytes?

Answer 20

Prophase I

Question 21

What stage of meiosis produces secondary spermatocytes/ oocytes?

Answer 21

Meiosis I

Question 22

What stage of meiosis produces spermatids/ ootid and polar bodies?

Answer 22

Meiosis II

Question 23

What follows meiosis to produce spermatozoa and the ovum?

Answer 23

Differentiation.

Question 24

Are sex chromosome defects or autosomal chromosome defects more likely to be fatal?

Answer 24

Autosomal chromosome defects.

Question 25

What is turner syndrome?

Answer 25

X chromosome missing in female.

Question 26

What is Kleinfelter syndrome?

Answer 26

Extra X chromosome in males.

Question 27

Vaguely compare the number of germ cells present in females at 16-20 weeks, at birth and at adulthood?

Answer 27

Peak number at 16-20 weeks of embryonic development. Significantly lower at birth. Continuos reduction through adulthood.

Question 28

Can one survive with chromosome 13 or chromosome 18 trisomy?

Answer 28

Survive gestation but not birth.

Question 29

What organ produces the follicle stimulating hormone?

Answer 29

Pituitary gland

Question 30

Why is it that during follicle maturation 50 follicles begin to mature but only one dominates and the others die?

Answer 30

The dominant follicle becomes FSH-independent and secretes inhibin. Inhibit inhibit pituitary FSH production, from which the other follicles die.

Question 31

What happens to the daughters of spermatogonium division?

Answer 31

One returns for renewal, while the other continues to divide.

Question 32

What cell expresses the SRY gene and produces anti- Mullerian hormone?

Answer 32

Sertoli cells.

Question 33

What is the function of the blood-testis barrier in the testis?

Answer 33

Spermatozoa are produced during puberty and have never been exposed to the immune system. If there were no blood barrier, the immune system would destroy spermatozoa.

Question 34

Why do spermatozoa share a cytoplasm through to differentiation?

Answer 34

To ensure they are the same and that there is no gender skewity.