Sex Determination & Gametogenesis

Question 1

initial event that determines whether the gonads will develop as testes or ovaries.

Answer 1

Sex determination

Question 2

subsequent events that ultimately produce either the male or female phenotype.

Answer 2

Sex differentiation

Question 3

Responsible for making the gametes

Answer 3

gonads

Question 4

the formation of gametes

Answer 4

gametogenesis

Question 5

Sex determination in mammals

Sex Determination: The Jost Paradigm

Answer 5

Chromosomal sex -> Gonadal sex -> Phenotypic sex

*Expanded model
Chromosomal sex -> Gonadal sex -> Hormonal sex -> Phenotypic sex -> Brain/Behavioral sex

Question 6

Sex-specific reproductive tract system

Primitive female tract = ________
Primitive male tract = ________

Answer 6

Mullerian duct; Wolffian duct

Question 7

BRAIN SEX DETERMINATION

Answer 7

Chromosomal (Genetics)
Hormonal (Endocrine)
Environmental (Epigenetics)

Question 8

is the study of heritable phenotype changes that do not involve alterations in the DNA sequence

Answer 8

Epigenetics

Question 9

Anteroventral periventricular nucleus (AVPV) in mouse brain is longer in (males, females)

Principal nucleus of the bed nucleus of the stria terminals (pBNST) is larger in (males, females)

Sexually dimorphic nucleus (SDN) is larger in (males, females)

Answer 9

females; males; males

Question 10

Which part of the mouse brain controls sexual behavior

Answer 10

Preoptic area (POA)

Question 11

Epigenetic mechanisms by which sex differences in the brain are established

Testosterone - Estradiol - Inhibit Dnmt - methyl groups are removed from DNA = Expression of genes necessary for masculinization of the POA and behavior

minus testosterone
Acetylation of histones results in the increased expression of genes necessary for programmed cell death in the female BNST - Constitutive Dnmt activity - Methylation of DNA in the POA = Repression of genes necessary for masculinization of the POA and behavior

Question 12

means “marriage partners”

Answer 12

gametes

Question 13

is the process by which sperm and eggs are produced from the germ cells in the gonads (testes and ovaries)

Answer 13

Gametogenesis

Question 14

Disorders of Sexual Development (DSD)

Answer 14

Turner syndrome
Klinefelter syndrome
GMD
Ovotesticular DSD

Question 15

different gene expression in males and females

Answer 15

dimorphism

Question 16

Endocrine Disrupting Effects on Sex of Bisphenol A (BPA)

Answer 16

Feminization of male fetuses
Infertility
Prostate cancer
Menstrual irregularities
Endometriosis
Breast cancer

Question 17

Sexual differentiation of the human brain is most likely a multifactorial process including both sex chromosome and sex hormone effects, acting in parallel or in combination

Question 18

gametogenesis in males

Answer 18

Spermatogenesis

Question 19

Gametogenesis in females

Answer 19

oogenesis

Question 20

in indifferent gonads, where do testes and ovaries originate?

Answer 20

intermediate mesoderm

Question 21

In the absence of SRY, _______ form

Answer 21

ovaries

Question 22

Sex Determination in Placental Mammals

Answer 22

Genital ridge - Bipotential gonad -
Ovary = Follicles - Estrogen = Female genitalia
Testis = Sertoli cells (AMH) & (Leydig cells) Testosterone - DHT = male genitalia

Question 23

a group of genetic disorders that affect the adrenal glands

Answer 23

Congenital Adrenal Hyperplasia (CAH)

Question 24

Site of Spermatogenesis

Answer 24

Testis

Question 25

Functional Organization of Testis

Answer 25

1. Seminiferous tubules (spermatogenesis) 2. Interstitial compartment (steroidogenesis)

Question 26

Parts of testis

Answer 26

Ductus deferens Epididymis Rete testis Tunica albuginea Seminiferous tubules Septae Testicular lobes

Question 27

Site of Oogenesis

Answer 27

Ovary

Question 28

Parts of female reproductive system

Answer 28

Vagina Cervix Uterus Fallopian tube Ovary

Question 29

Endocrine organ in ovary

Answer 29

Corpus luteum

Question 30

Origin of Primordial Follicles

Answer 30

Germ cell cyst formation in fetal ovary

Question 31

Mechanisms of germline specification

Answer 31

Preformation (Localized germ plasm) Induction (No maternal germ plasm)

Question 32

Life Cycle in Most Animals (Diplontic) = Main form is diploid

Question 33

Phases of Gametogenesis

Answer 33

1. Migration of germ cells (into the gonads) 2. Increase in the number of germ cells 3. Reduction in chromosomal material of germ cells (meiosis) 4. Differentiation of the sperm and egg

Question 34

is the chromosomal foundation of reproduction, errors in this important process may lead to aneuploidy and/or infertility.

Answer 34

Meiosis

Question 35

Meiotic prophase I

Answer 35

1. Leptotene = Recondensing 2. Zygotene = Synaptonemal complex 3. Pachytene = Crossing over/Recombination 4. Diplotene = Chiasmata in bivalent; separation of homologues; 1st meiotic arrest (Dictyate arrest) 5. Diakinesis = Chromosomes are fully condensed

Question 36

Type A vs. Type B spermatogonia

Answer 36

Type A undergoes mitosis to produce type B spermatogonia Type B undergoes meiosis to produce primary spermatocytes

Question 37

Development of the mammalian ovarian follicle. Follicles, consisting of somatic cells (blue) surrounding an oocyte (yellow), grow within the ovary. Oocytes within the smallest (primary and preantral) follicles are meiotically incompetent and will not mature spontaneously Early antral with FSH -> Preovulatory = meiotically competent

Question 38

sequence of post-meiotic changes by which spermatids are transformed into spermatozoa

Answer 38

Spermiogenesis

Question 39

Phases of spermiogenesis

Answer 39

Spermatid Golgi phase Acrosomal phase Early maturation phase Mid-maturation phase

Question 40

Parts of spermatozoa

Answer 40

Head Neck Middle piece Principal piece End piece

Question 41

Formation of acrosome in developing spermatids as seen under EM.

Answer 41

1. Appearance of a proacrosomal granule in an acrosomal vesicle 2. Enlargement of the acrosomal vesicle and its adherence to the pole of the nucleus. 3. Spreading of the acrosomal vesicle over the anterior hemisphere of the nucleus to form an acrosomal cap

Question 42

is a technology that creates gametes outside the body (in vitro) from somatic (non‐reproductive) cells, stem cells or progenitor cells

Answer 42

In Vitro Gametogenesis (IVG)

Question 43

Haplodiplontic life cycle in plants.

Question 44

Sex Determining Pathways in Land Plants: 1. Environmental determination of sex in the homosporous fern Exogenous cue: + Antheridiogen = male 2. Chromosomal determination of sex in persimmons 3. Sex determination in monoecious melons Endogenous cue: Ethylene Off = male

Question 45

GAMETOGENESISa : PLANTS Lack of pre-determined germ line, instead, possess reproductive meristem Gametes are formed by meiosis followed by mitosis and differentiation

Question 46

Function of synergids

Answer 46

Will become the endosperm

Question 47

Gamete Formation in Arabidopsis

Answer 47

Meiosis first before mitosis