Introduction to Development & Gametogenesis

Question 1

How does embryological age differ from menstrual age?

Answer 1

Embryological age begins at fertilization. Menstrual age begins on the date of the last menstrual period, which is about 2 weeks before fertilization.

Question 2

In what phase of the cell cycle does DNA synthesis take place?

Answer 2

S Phase

Question 3

True/False. Meiosis results in identical cells.

Answer 3

False. During Meiosis I, sister chromatids cross over leaving two cells that are non-identical.

Question 4

When does Meiosis II take place in the oocyte?

Answer 4

After fertilization by the sperm. Meiosis II results in one mature oocyte and 1-3 polar bodies

Question 5

When does spermatogenesis begin? How does this differ from oogenesis?

Answer 5

Spermatocytes do not begin meiosis I until puberty in males. Once spermatogenesis begins, it does not stop until death and results in 4 equally viable spermatids. Conversely, oocytes undergo meiosis I during fetal development. The oocytes are arrested in meiosis I before birth. Meiosis I resumes just prior to ovulation, with meiosis II beginning after fertilization. Meiosis II results in only one mature oocyte.

Question 6

When should intercourse take place for optimal opportunity for fertilization?

Answer 6

Two or three days before ovulation

Question 7

What produces progesterone during ovulation in preparation for fertilization?

Answer 7

Curpus Luteum

Question 8

Release of what hormone stimulates maturation of the oocyte before ovulation?

Answer 8

FSH

Question 9

The ampulla of the fallopian tube is where what commonly takes place?

Answer 9

Fertilization

Question 10

When the egg and sperm pronuclei come together and chromosomes intermingle, what is formed?

Answer 10

Zygote (2n)

Question 11

What is the name of the membrane surrounding the zygote during early cell division, which later disintegrates during implantation in the uterus?

Answer 11

Zona pellucida

Question 12

When cells of the zygote become indistinguishable, it becomes called…

Answer 12

morula

Question 13

What gives rise to extraembryonic structures like the placenta?

Answer 13

Trophoblast

Question 14

As cells further divide and an inner cell mass develops, the morula becomes what?

Answer 14

Blastocyst

Question 15

What is the failure of chromosomes to split during gametogenesis?

Answer 15

Nondisjunction

Question 16

What diseases are associated with sex chromosome nondisjunction?

Answer 16

Klinefelter Syndrome (XXY)

Turner’s Syndrome (X monosomy)

Super-female (XXX)

Jacob’s Syndrome (XYY)

Y monosomy