Test 3: 56 Flashcards
___ is propagation of genetic information into offspring through combining the genetic information from two individuals (mother and father)
sexual reproduction
two phases of the life cycle of animals with sexual reproduction
One is the diploid phase where cells have two copies of genome in cells, one from mother, one from father.
The other phase is haploid phase where germ cells, undergo meiosis by which they generate gametes that has only 1 copy of genome after shuffling the paternal and maternal chromosomes through the process called recombination
Upon fertilization, these two haploid gamates unite to re-establish the diploid phase.
___phase where cells have two copies of genome in cells, one from mother, one from father.
diploid
___ phase where germ cells, undergo meiosis by which they generate gamates that has only 1 copy of genome after shuffling the paternal and maternal chromosomes through the process called ___
haploid
recombination
Upon fertilization, these two haploid gamates unite to re-establish the ___ phase.
diploid
haploid phase have how many copies of each chromosome?
one of each
meiosis leads to ___
father and mother get mixed (recombination) creates
sperm and oocyte (haploid )
diplontic life cycle
most animals
most life cycle is diploid phase
haplontic life cycle
most of life cycle is in haploid stage
ulothrix (sea vegtable)
haploid diploid life cycle
mix of haploid and diploid evenly
ulva
bacteria reproduce ___
asexually
why have sex?
- Sex procures offspring with a new combination of DNA resulting in genetic variation among individuals:
- Increased adaptation to changing environment
- Enables sexual selection: some individuals out reproduce others of a population because they are better at securing mates for sexual reproduction
advantage and disadvantage of asexual reproduction
identical offspring
very fast
disadvantage
all faulty genetic material is passed on
advantage and disadvantage of sexual reproduction
advantage
genetic variation
disadvantage
slower
takes lots of energy and time
horizontal gene transfer is how ___ exchange genetic material between cells
bacteria
ways bacteria can transfer information
conjugation
transformation
transduction
There are a number of different mechanisms that determine whether one individual become __ or __
male or female.
sex determination is influenced by ___ or ___
genetic sex determination
environmental sex determination (temp, visual cue and position)
limpet’s position in the stack
type of environmental sex determination
larva
1st one is female, will attract new larva which will become male and mate. then top one will change into female and attract new larva ect ect
•Temperature-dependent sex determination (TSD) in ___ and crocodiles
turtles
the histone demethylase KDM68
increase in global temperatures changes sex of turtles and crocodiles
high temp Dmrt1 blocked → girls
low temp Dmrt1 activated → male
visual cues in fish can change ___
sex determination
type of environmental cue
smaller fish will become female
bigger fish will become male
genetic sex
XX = ovary
XY= testis
gonadal sex
ovary vs testis
phenotypic sex
internal and external genitalia
psychological sex
brain sex
gender identity
partner preference
karyotype
chromosome lined up with each other
will show XX for female
XY for male
XX- XO genetic sex
grasshopper
XX female
XO male
XX- XY system
mammals
XX female
XY males
ZZ-ZW system
birds, snakes, butterflies, some amphibians, and fishes
ZZ male
ZW female
haplodiploidy system
haploid set- male
diploid set- female
bees, wasps, ants
___ is a master regulator in mammalian sex determination
SYR
sorry you are a boy
SRY knockout XY mice will do what
male to female sex reversal
SRY transgenic XX mice
female to male sex reversal
TDF
testis determining factor
SYR = testis
who discovered gonadal sex
alfred jost
castration of a rabbit fetus
primitive gonads
will turn into male or female
wolffiann duct → male things
mullerian duct→ female things
wolffian (___) duct will develop into ___
mesonephric duct
epididymis
vas deferens
seminal vesicles
ejaculatory duct
male things
mullerian (___) duct will turn into ___
paramesonephric
fallopian tubules
uterus
upper part of vagina
female things
when does primitive gonad differentiate?
week 9-10
XY testis will form and mullerian duct will break down
XX: ovaries will form and wolffian duct will break down
jost hypothesis for sex determination
•Phenotypic sex (internal/external sex organ development) is determined by the gonadal sex (testis/ovary)
what did jost experiment do and show
removed gonadal sex in fetus
male → female
female → female
showed female is default stage. ovary not needed to develop XX
testis needed for phenotypic sex of XY, testis will support wolffian duct turning into male things and will inhibit mullerian duct from turning into female things
___ not necessary for the female phenotypic sex development in XX
•Ovary
___ is necessary for the male phenotypic sex in XY
•Testis
jost transferred testis on one side of fetus to show
on side of testis wollfian duct is present and mullerian duct is absent
in jost experiment grafter testosterone creates ___
wolffian duct will persist in female
- Testosterone is sufficient to support Wolffian duct.
- Testosterone does not affect Mullerian duct.
suggests the presence of a “ mullerian inhibitory susbstance”
mullerian inhibitory substance was found/ proven in ___
1986
anti-mullerian hormone
at 6 weeks gonads are ___
undifferentiated- neither male or female
how is male phenotype formed
gonad → testis which produces testosterone which stimulates formation of wolffian tubes into male things. Testis will also produce anti-mullerian hormone which will cause mullerian tubes to degrade
how is female phenotype formed
default setting
gonad→ ovary. wolffian duct degrades naturally and mullerian duct turns into female things
Gartner’s duct cyst
Wolffian duct remnant
Benign vaginal cyst, occurring along the lateral walls of the vagina
Often asymptomatic
Can cause Infections, bladder dysfunction
___ are cyst in female caused by wolffian duct not breaking down all the way
gartner’s duct cyst
at 6 weeks of development what external genitalia is seen
identical in male and females
genital tubercle surrounded by genital swelling
testosterone will turn external genitalia into
penis
5 alpha reductase deficiency
•The Enzyme converting testosterone into dihydrotestosterone (DHT), a potent androgen critical for the development of external genitalias (prostate, penis, scrotum)
external females will develop male external genitalia during puberty
treatment: finasteride which is a 5α-reductase inhibitor used for benign prostatic hyperplasia (BPH) treatment.
how to treat 5α-reductase deficiency
5α-reductase inhibitor, finasteride, used for benign prostatic hyperplasia (BPH) treatment.
•Alfred Jost found that the testis directs the phenotypic sex through producing ___ and ___
testosterone and AMH (anti-Mullerian hormone).
•There are two sex determination systems, genetic vs ___ sex determination
environmental
__ on Y chromosome is the master regulator of mammalian sex determination
SRY
