Chapter 6 pt 2 Flashcards
In ________ Females are rock-dwelling marine worms and males live inside the female uterus
echiuroid worm
- bonellia viridis
in the echiuroid worm, larva that land on the sea floor become _______ while larva that land in the female’s mouth differentiate into _______
1) females
2) males
- example of locational sex determination
In slipper snails, individuals pile up on each other and the young snails are always _______
male
- older=flexible sex cuz male system degenerates
In slipper snails, if attached to a female the snail will become _______
male
In slipper snails, if removed from the pile, or presence of lots of males, the snail will become _______
female
- once female it will not revert to male
Many _______ species are able to change their sex based on social interactions. These involve the ________ system
fish
neuroendocrine
in many fish, _______ induces aromatase
cortisol
In gobies a school typically contains _______ male(s) and _______ female(s)
one
many
- if male is removed, dominant, aggressive female becomes new male in a week
Newly formed primordial germ cells enter the _______ then migrate forward into the ________
hindgut
bipotential gonad
- traveling niche
During their migration, PGC’s are surrounded by supporting cells, which secrete _______ which is necessary for PGC motility and survival
stem cell factor (SCF)
Primordial Germ cells (PGC’s) are ________ becoming either egg or sperm and initially form in the _______ portion of the embryo before migrating
bipotential
posterior
What are the 5 proteins that repress PGC’s as they travel?
1) VASA
2) Nanos
3) Pumilio
4) Tudor
5) Piwi
_______ - required for germ cells in all animals. It is a RNA binding protein that activates germ-cell specific mRNA
VASA
_______ form repressive dimers with _______. Blocks mRNA translation by binding to the 3-UTR
Nanos
Pumilio
- prevents cell from becoming germ layer and prevents cell cycle
_______ proteins interact with _______ proteins to transcriptionally silence portions of the genome especially active transposons
Tudor
Piwi
- Drosophila females carrying extra Tudor are sterile
The transcription factor _______ is the gatekeeper of meiosis for PGC’s
Stra8
In females meiosis of PGC’s begins in the _______ gonads
embryonic
In females, Stra8 is upregulated by _______ and _______ produced by adjacent kidneys
Wnt4
Retinoic acid
In Males, meiosis of PGC’s does not begin until after _______
puberty
In males, Stra8 is down regulated by _______, and retinoic acid produced by kidneys is degraded by _______ enzyme
Fgf9
RA degrading enzyme
Where is the retinoic acid degrading enzyme produced?
testis
During puberty, RA is again synthesized by _______ and induces Stra8 expression for sperm stem cells to undergo meiosis
Sertoli cells
What are the 3 major phases of spermatogenesis?
1) proliferation
2) meiotic phase
3) shaping (spermiogenesis)
_______: Sperm stem cells (spermatogonia) increase by mitosis
phase 1, proliferation
_______: cell go through both meiotic division producing haploid cells
phase 2, meiotic phase
_______: post-miotic shaping. Round spermatids eject most of the cytoplasm and take on the typical streamlined sperm shape
phase 3, shaping
- spermiogenesis
PGC’s (Gonocytes) arrive at the _______ and become undifferentiated _______
genital ridge
- niche near Sertoli cells, Leydig cells, and testicular blood vessels
spermatogonia
Spermatogenesis 1:
Mitotic proliferation of undifferentiated spermatogonia amplify these cells into population of differentiating _______
Type-A spermatogonia
Spermatogenesis 1:
Type-A spermatogonia respond to Stra8 and become _______
Type-B spermatogonia
Spermatogenesis 1:
Type-B spermatogonia divide by _______ to produce _______
mitosis
primary spermatocytes
Spermatogenesis 2:
Primary spermatocytes divide by _______ to produce _______
meiosis (first division)
secondary spermatocytes
Spermatogenesis 2:
Secondary spermatocytes then complete _______ to produce _______
meiosis (second division)
Spermatids (haploid)
Spermatogenesis:
Everything is connected by _______ throughout this process, which is eventually lost as sperm differentiates into _______
cytoplasmic bridges
spermatozoa
Spermiogenesis:
the acrosomal vesicle is constructed by the _______
golgi
Spermiogenesis:
A _______ begins to form opposite the acrosomal vesicle
single flagella
Spermiogenesis:
Histones are replaced with _______ which completely shuts down transcription and DNA assumes an almost crystalline structure
protamines
Spermiogenesis:
DNA _______ to paternal patterns is established
methylation
Spermiogenesis:
Almost all _______ is shed, and forming sperm are exported to the _______ for storage
cytoplasm
epididymis
- exosomes (contain ncRNA) activate repress genes
Where does final differentiation of sperm occur?
female uterus
_______: PGC’s reaching the developing ovary divide rapidly between the 2-7th months of gestation. Produce 7 million oogonia
Proliferation
- most die
Surviving oogonia undergo the _______ to become primary oocytes
first meiotic division
Primary oocytes remain in _______ stage of meiosis
diplotene
- first stage of prophase 1
_______ from the pituitary gland removes the division block on primary oocytes and meiosis resumes
Leuteneizing hormone (LH)
LH causes oocyte maturation, which synthesizes proteins that make it _______ to fuse with a sperm and divide after fusion
competent
Secondary oocytes remain in _______ stage of meiosis until fertilization
metaphase II
Asymmetric cytokinesis at meiosis I/II generate _______ containing a nucleus but essentially no cytoplasm
polar bodies
A large proportion of oocytes have chromosomal abnormalities, primarily _______
aneuploidy
- incorrect number of chromosomes
Maternal age correlates with an _______ risk
increased
- @ age 20 = 3-5%
- @ age 40+ = 35%
What are two causes of aneuploidy in aging oocytes?
1) degeneration of cohesin
2) instability of linkage between the kinetochore and meiotic spindle
_______ forms rings around sister chromatids at the kinetochore and around the chromatin arms that unite sister chromatids
cohesin
Card about separase APC/C Sgo2 Cohesin
im confused
The _______ forms during prophase I of meiosis
synaptonemal complex
The synaptonemal complex is held together by interlocking units of _______
SYCP1
The ___-terminus of SYCP1 binds to DNA
C
The ___-terminus of SYCP1 binds to other units of itself
N
