bio 203 1&2

asexual reproduction: mitosis or meiosis
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Terms in this set (138)
asexual reproduction: mitosis or meiosis
mostly mitosis but occasionally meiosis
3 mechanisms for asexual reproduction
fission, budding, fragmentation
fission
separation of parent into two or more individuals of approximately equal size
budding
new individuals splitting off from existing one where the offspring may or may not detach
fragmentation
breaking of body into several pieces and each of these pieces developing into complete adults; must be followed by regeneration
most common form of asexual reproduction
fission
parthenogenesis
-reproductive female produces eggs and the eggs can develop without being fertilized by a male.
-can be done by either mitosis or meiosis.
-enables organisms to switch between normal sexual reproduction and asexual reproduction.
gametes: haploid or diploid
haploid
zygote: haploid or diploid
diploid
two types of gametes
ovum and spermatozoon
ovum-the egg of a female -usually relatively large and nonmotilespermatozoon-male -usually small and motilewhere do genes come fromfusion of haploid cellshow does the ovum movefollows the currents or whatever fluids are present. does not move on its ownwhat part of the sperm propels it aroundthe tailhermaphroditismindividual has both male and female reproductive systems, a solution to the special problem of sexual reproductiona common example of a hermphroditic organismearthworms are hermaphrodites but still require a partnerwhen does fertilization occur in the earthwormfertilization takes place when the earthworm creates a cocoon and deposits the eggs. this is when the eggs will be fertilized and not in the time of insemination.sequential hermaphroditismindividual reverses its sex during its lifetime. changes its gender when it wants or needs to.what drives sequential hermaphroditismhormonesexample of organism that udnergoes sequential hermaphroditismbluehead wrassewhat are the cycles of reproductive activity controlled byhormones and environmental cues2 mechanisms of sexual reproductionexternal and internal fertilizationexternal fertilization is pretty much exhibited by what type of organismsaquatic organismsin internal fertilization, wehre does the zygote maturein the reproductive tractclasping reflexthink frogs and how they exhibit external fertilization, the male frog responds to the pheromones released by reproductively ready female by exhibiting a clasping reflex, fertilizing the eggs as they come out of the femalespecies with external fertilization usually produce a very _____ number of offspring and treat it with _____large; little or no protection & carespecies with internal fertilization produce _____ number of offspringsmaller; and provides protection/protective coating, development within the reproductive tractautosomesnot the sex chromosomesX chromosomevery big and has lots of genes on itY chromosomevery smallhow many chromosomes will a gamete have23mullerian structuresfallopian tubes, uterus, upper half or third of the vaginawolffian systemkidneys and ureters, prostate gland, seminal vesicles, vas deferensSRY geneleads to the development of testes by producing a number of proteins that will cause the gonads to develop in such a way that the cortex of the gonadal tissue regresses and the medullary part of the gonadal tissue develops into testeswhat happens if you dont have SRY geneyour medullary part of hte gonadal tissue will regress and the cortex of the gonadal tissue will become ovarieswhat does the wolffian system need in order to developtestosteronewhat allowed for testes to developSRY genewhat are the two main cells on testesleydig and sertoli cellsleydig cellsproduce testosteronesertoli cellmakes and releases Antimullerian hormone AMHAMHtargets mullerian system and causes it to degernatewhat is the one thing under direct genetic controldifferentiation of the gonadsexternal sexual characteristics that develop in femalesgenital tubercle--> clitoris urethral fold closes to form urethra but not completely closed labioscrotal swelling becomes the labiaDHTdihydrotestosterone; some of the testosterone becomes DHT, a crucial hormone that allows for external masculinizationexternal sexual characteristics that develop in malesgenital tubercle becomes elongated and becomes penis, urethra fold closes completely, labioscrotal swelling becomes the scrotum, testes descend from the abdomen down into the scrotum5 bipotential structuresgenital tubercle, urethral folds and groove, labioscrotal swelling, cortex of gonad, medulla of gonadgenital tubercle becomesclitoris in female, glans penis in maleurethral folds and groove becomeslabia minora, opening of vagina and urethra in female and shaft of penis in malelabioscrotal swellingslabia majora in female and shaft of penis and scrotum in malecortex of gonadforms ovary in female and regresses in malesmedulla of gonadregresses in females and forms testes in malesprecursor of every steroid hormonecholesterolprecursos of sex hormonesprogesteroneenzyme that converts testoterone into estrogenaromataseandrogentestosterone and DHTenzyme critical in converting testoterone to DHT5 alpha reductasepropesia5 alpha reductase inhibitor that is currently being used to medicate male baldnessandrogen insensitivity syndromedisorder where a phenotypic female is a genotypic male. although the testes will develop and secrete androgens (testosterone and DHT) its androgen receptors will be defective and the tissues will be unable to respond to the androgens. becuase there is no DHT available, the default pathway for female phenotype will undergo.where does a lot of the development of oocytes occurin uterowhere are the primary oocytes that are ever going to be developed going to bein the ovarieswhat happens when ovaries and testes differentiatestem cells are producedoogoniastem cells that will become female gametesspermatogoniastem cells that will become male gameteshow are these stem cells reproducedby mitosiswhat kind of division and how many is required for the production of gametestwo meiotic cell divisionswhen do the primary oocytes get produced?during the embryonic period.speratidsprecursor cells of spermpolar bodythe other smaller cell that is produced along with a secondary oocyte during meiosis that eventually degenerates. it has a full complement of the genetic materialwhich sex produces androgen and which sex produces estrogenboth sexes produce androgen and estroenadrenal glandssecretes small amounts of sex steroidsgranulosa cellsconverts testoterone to estradiol/estrogen bc they have a lot of aromatase, the enzyme that converts testosterone to estrogenGnRH- gonadotropin releasing hormone - peptide hormone that is released by cells in the hypothalamus - released into portal vessels - comes down to the pituitary and triggers the release of LH and FSHLH-triggers leydig cells to make testoterone - will induce negaitve feedback back to the brain both at the pituitary gland level and the hypothalamus level to inhibit the release of GnRH and pituitary level of LH and FSHgonadotropin level and effect of low estrogen or androgengonadotropin level increases and no negative feedbackgonadotropin level and effect of moderate estrogen or androgennegative feedback and gonadotropin level decreasesgonadotropin level and effect of high or androgennegative feedback and gonadotropin level decreasesgonadotropin level and effect of high estrogen levelspositive feedback and gonadotropin level increases, causing an increase in LH and FSH releasewhy is positive feedback in response to high estrogen levels crucialit is required in order to get the LH surge needed to produce ovulation during the ovarian cycle. the LH surge will trigger ovulationtwo external reproductive organs of malepenis and scrotuminternal reproductive organs of maletestes, accessory glands, and ductslargest accessory gland in malesprostate glandprostate glandcompletely surrounds the urethrabenign prostatic hypertrophyprostate gland enlarges and compresses the urethra, causes difficulty in urinationwhat is key to erectionvasodilation that results in an increase amount of blood coming into the penis and creating vasocongestion; an increase in pressure will cut off the veins that drain the blood in the penisboulbourethral glandprovides secretions that add certain components to semenPathway for spermSEVEN UP seminiferous tubule epididymis vas deferens ejaculatory duct urethra peniswhere is sperm generatedseminiferous tubulestestes (gonads)produces sperm cells and hormonesaccessory glandssecretes products essential to sperm movementductscarries sperm and secretionshow is the acidic environment of the vagina conditionedsemen conditions the vagina by its secretions that come primarily from the bulbourethral gland and from the prostatewhat is semen composed of (8)sperm, mucus, water, buffers, nutrients, enzymes, zinc, and prostaglandinssource and function of spermseminiferous tubules and gametessource and function of mucusbulbourethral glands and as lubricantsource and function as waterall accessory glands and provides liquid mediumsource and function of buffersprostate, bulbourethral glands and neutralize acidic enviornment of vaginasource and function of enzymesseminal vesicles and prostate, clots semen in vagina than liquifies the clotsource and function of zincunknown source and functionsource and function of nutrients (4 types of nutrients)fructose, citric acid, vitamin c, carnitine seminal vesicles, prostate, seminal vesicles, epididymis nourishes spermlocation of leydig cellsbetween the seminifeorus tubules in interstitial fluid in interstitial spacesertoli cells-very large -provides supportive and nutritive role for the developing sperm cells - responds to testosterone by providing material for sperm cells - responds to FSHthe cell types in the seminiferous tubule 5spermatagonia spermatocytes primary and secondary spermatids leydig cells sertoli cellswhat does the head of sperm containgenetic material that is in the nucleuesacrosomeat the very top of a sperm cell head contains enzymes to aid fertilization, helping the sperm penetrate the ovumwhat happens upon FSH releaseupon being released fromt he pituitary, it is targeting the sertoli cells and stimulates them to help with sperm productionwhat does LH dotriggers the leydig cells to make testoteroneinhibincomes from the sertoli cells, works to give negative feedback to FSHandrogen binding proteinproduced by sertoli cells released into fluid in the lumen of seminiferous tubule binds androgen helping androgen from diffusing back out of the seminiferous tubuleswhat happens to sperm once maturereleased into lumen of the seminiferous tubules very diffferent from form of spermatocytes of the spermatids not fully functional and will be unable to move in fluid thus will move through bulk flow into the epidydimuswhen is the sperm cell fully mature and motileby the time they get pushed into the vas deferensexternal reproductive anatomy of femaleclitoris, labia, vaginal openinginternal reproductive organs of femaleovaries, ducts and chambersmenstrual cycleendometrium enlarges and then breaks down and is dischargedovarian cycleoogenesis leading to ovulationhow does the ovum move ino the fallopian tubebulk flowwhat kind of muscle is the uterussmooth muscleendometriumepitherlial structure the inside lumen of the uterus uterine cavity an endocrine structurewhat changes significantly during the menstrual ovary cycleendometrium- by getting much larger during the ovarian cycle and then at the end of the cycle during menstruation the endometrium is cut off of the uterus, producing menstrual flowwhere do primary follicles developin uterowhen do the follicles start to developthey start to develop in response to FSH-- a small number of follicles will develop and one of them in particular will develop the fastest and will odminatewhat happens while several follicles develop and get largerthe support, granulosa, and theca cells will proliferate immensely and will create a fluid filled chamber called the atrium, taking about two weekswhat happens after two weeksa surge in LH will rupture the follicle and push out the ovum aka the ovulated oocyte which ends up in the fallopian tubeswhat happens to the support cells that were presnt in the ruptured folliclethey become what is called the corpus luteum and will stay in the ovary, syntehsizing and producing hormones like crazy like before for another two weeks or sowhat has happened if the corpus luteum degeneratesit means that there was a futile fertilization of the ovum and there was not a successful pregnancyfollicular phase of the ovarian cyclethe first half of the cycle, when the development of the ovarian follicles dominateluteal phase of the ovarian cyclethe second phase of the ovarian cycleat what day of the menstrual cycle does the endometrium begin to slough offday 1 of the menstrual cyclewhen does ovulation usually occurat around the half time of the cyclemenses portion of the cyclethe beginning of the cycle that is characterized by menstrual flowproliferative phase of the cycleendometrium proliferates, becomes thicker and becomes receptive for a fertilized zygote for implantationfollicular phase =menses + proliferative phase; during the first 14 days of cycle is when we have developing follicle and developing oocyte that leads up to ovulationwhen is there positive feeefback for estrogenwhen stimulating follicular development while at the same time inhibiting LH and FSH releasewhat does this positive feedback lead tofollicles that have developed the most will keep developing while the follicles that are still dependent on FSH for develpment will stop developingwhat does progesterone do for endometriumit supports it- so as long as progesterone levels are high, the endometrium stays thick and lush and receptive to implantation via fertilized zygotewhat is the relationship between corpus luteum and progesteronit is a specialized structure to produce progesteronewhat happens if fertilization did occura zygote would develop and implant itself into endometrium the embryo will start to produce a peptide called human chorionic onadotropin hCGwhat does hCG doit feeds to the corpus uteum and supports the corpus luteum and maintains it so it doesnt degenerate. it continues to produce progesterone to maintain the endometrium and this will go on for weeks until the placenta to take over the role of progesterone producer ultimatey increases progesterone and estrogen as it supports the corpus luteum and inhibits GnRH