Gametogenesis And Fertilization

Question 1

During meiosis I, the 46 chromosomes are duplicated into ________ ___________

Answer 1

Sister chromatids

Question 2

There are 30-40 ___________ during each mejoría I division, allowing for interchange of chromatid segments between homologous chromosomes

Answer 2

Crossovers

Question 3

Ploidy refers to the number of _________

Answer 3

Chromosome copies

Question 4

N refers to the number of ________

Answer 4

Chromatid copies

Question 5

Mitosis results in DIPLOID/HAPLOID 2N/4N cells

Answer 5

Diploid, 2N

Question 6

Meiosis I begins with HAPLOID/DIPLOID 4N/2N cells

Answer 6

Diploid, 4N

Question 7

Meiosis I ends with HAPLOID/DIPLOID 2N/1N cells

Answer 7

Haploid, 2N

Question 8

Meiosis II ends with HAPLOID/DIPLOID 2N/1N cells

Answer 8

Haploid, 1N

Question 9

In meiosis, the process of chromosomes lining up for crossing over is called ______ and occurs during which phase?

Answer 9

Synapsis, prophase I

Question 10

Germ cells are formed in the ________ and move to the wall of the yolk sac during week __ then migrate to developing gonads during week ___

Answer 10

Epiblast, 2, 4

Question 11

Primordial germ cells migrate from around the developing gut tube to the _______ _______

Answer 11

Gonadal ridge

Question 12

The SRY gene encodes ____ which induces the formation of ________ ________

Answer 12

TDF, seminiferous fords

Question 13

The X chromosome downregulates _____ while ______ contributed to ovarian differentiation

Answer 13

SF1, Wnt4

Question 14

It takes ___ days for spermatogonia to develop into mature spermatozoon

Answer 14

74

Question 15

About how many sperm cells are produced daily?

Answer 15

300 million

Question 16

Spermiogenesis is the transformation of ______ to ______

Answer 16

Spermatids to spermatozoa

Question 17

What occurs during spermiogenesis?

Answer 17

Cytoplasm is shed
Formation of neck, middle piece, and tail
Condensation of nucleus
Formation of acrosome

Question 18

Just prior to ovulation, the 1st/2nd meiotic division is completed

Answer 18

1st

Question 19

Which hormone surged during ovulation?

Answer 19

LH

Question 20

Oocyte transport from the fimbria to the ampulla of the uterine tube is aided by what process?

Answer 20

Peristalsis

Question 21

Oogenesis is not complete until ______

Answer 21

Fertilization

Question 22

About 7 million oogonia are present at what point in a female’s life?

Answer 22

5th prenatal month

Question 23

During oogenesis, secondary oocytes are initially formed just prior to ________ with the completion of meiosis I/I

Answer 23

Ovulation, I

Question 24

What is capacitation?

Answer 24

Removal of glycoprotein coat and seminal proteins from acrosomal membrane

Question 25

Where does capacitation occur?

Answer 25

Uterine tube

Question 26

What is the acrosome reaction?

Answer 26

When sperm binds to the ZP3 receptor on the zona pellucida, the breakdown of the acrosomal membrane releases enzymes that digest a path through the ZP

Question 27

1st stage of fertilization

Answer 27

Penetration of the corona radiata, aided by hyaluronidase, acrosin, and tubal enzymes

Question 28

2nd stage of fertilization

Answer 28

Penetration of the ZP - cortical rxn: release of cortical granules within oocyte membrane - zonal rxn: cortical granules alter zonal proteins, making ZP impermeable to other sperm

Question 29

3rd stage of fertilization

Answer 29

Fusion of oocyte and sperm membranes

Question 30

Two components of the cortical reaction

Answer 30

Fast block: Na influx triggered by ZP3 binding changes membrane potential Slow block: ZP3 binding activates G protein cascade that raises intracellular pH

Question 31

4th stage of fertilization

Answer 31

Completion of meiosis II and formation of female pronucleus

Question 32

5th stage of fertilization

Answer 32

Formation of male pronucleus

Question 33

6th stage of fertilization

Answer 33

Formation of zygote (fusing of pronuclei)

Question 34

Fertilization stimulates the secondary oocyte to complete _____ meiotic division

Answer 34

2nd

Question 35

The secondary oocyte is halted in which phase until fertilization?

Answer 35

Metaphase II

Question 36

Zygote Week 1 events

Answer 36

1-2: blastomere, compaction 3: morula 4: blastocyst (trophoblast + embryoblast) 5: hatching (degeneration of ZP)

Question 37

Implantation of zygote normally occurs in the ______ wall of the uterus

Answer 37

Superior, posterior

Question 38

Totipotentiality

Answer 38

Could be anything Ex. Blastomere

Question 39

Pluripotentiality

Answer 39

Can be any embryonic cell but not trophoblast cell Ex. Embryoblast

Question 40

Multipotentiality

Answer 40

Commutes to becoming cells that have a particular function

Question 41

Describe the start of implantation

Answer 41

The syncitiotrophoblast invades the endometrium via enzymatic erosion. Hypoblast forms under embryoblast

Question 42

Describe day 8 of implantation

Answer 42

Amniotic cavity develops Embryoblast becomes hypoblast and epiblast Trophoblast becomes cytotrophoblast and syncitiotrophoblast

Question 43

Describe day 9 of implantation

Answer 43

Amnioblasts line amniotic cavity Hypoblast cells form membrane called exocoelomic (Heuser’s) membrane Blastocyst cavity = exocoelomic cavity

Question 44

What happens on day 11-12 post-fertilization?

Answer 44

Formation of chorionic cavity

Question 45

What happens on day 13 post-fertilization?

Answer 45

Extraembryonic mesoderm differentiates into somatic mesoderm and splanchnic mesoderm

Question 46

What happens on day 14 post-fertilization?

Answer 46

Localized area of hypoblast cells become columnar, this prechordal plate is an organizer of the head region

Question 47

If sperm count/motility is too poor for IUI or IVF, what can be done?

Answer 47

Intracytoplasmic sperm injection

Question 48

If there is no sperm in the ejaculate, what can be done?

Answer 48

Testicular sperm extraction