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Bio |! 351 |! Module |! 2 |! Exam |! with |! precise |!
detailed |! answers
5 |! unique |! stages |! of |! prophase |! - |! Correct |! answer |! ✔Leptotene |! -> |! Zygotene |! -
Pachytene->Diplotene->Metaphase |! I |! and |! Diakinesis Leptotene |! - |! Correct |! answer |! ✔Means |! "thin |! thread" |! DNA |! replication |! has |! occurred |! - |! cell |! is |! now |! 4N Each |! chromosome |! consists |! of |! 2 |! chromatids Chromatin |! is |! stretched |! out |! thinly, |! not |! condensed, |! can't |! identify |! individual |! chromosomes Telomeres |! have |! attached |! along |! the |! nuclear |! membrane Zygotene |! - |! Correct |! answer |! ✔Homologous |! chromosomes |! pair |! side |! by |! side, |! this |! is |! synapsis Characteristic |! of |! meiosis, |! not |! in |! mitosis Requires |! formation |! of |! synaptonemal |! complex Configuration |! formed |! by |! the |! 4 |! chromatids |! and |! the |! synaptonemal |! complex |! is |! referred |! to |! as |! a |! bivalent |! or |! tetrad Synaptonemal |! Complex |! - |! Correct |! answer |! ✔Requires |! a |! nuclear |! membrane |! to |! be |! present
Ladder-like |! structure |! made |! of |! protein |! with |! central |! elements |! and |! two |! lateral |! bars Chromatin |! is |! associated |! with |! the |! two |! lateral |! bars |! and |! the |! chromosomes |! are |! then |! joined |! together |! and |! to |! the |! nuclear |! membrane Pachytene |! - |! Correct |! answer |! ✔Means |! "thick |! thread" Chromatids |! thicken |! and |! shorten Individual |! chromatids |! can |! now |! be |! distinguished |! by |! light |! microscopy Crossing-over |! may |! occur |! and |! continues |! into |! diplotene Diplotene |! - |! Correct |! answer |! ✔Crossing-over |! continues |! into |! this |! stage Synaptonemal |! complex |! breaks |! down |! and |! the |! two |! homologous |! chromosomes |! start |! to |! separate Chiasmata: |! regions |! at |! which |! crossing |! over |! is |! occuring This |! only |! occurs |! between |! regions |! of |! homologous |! genes Metaphase |! I |! and |! Diakinesis |! - |! Correct |! answer |! ✔Means |! "moving |! apart" Kinetochores |! move |! away |! from |! one |! another Chromosomes |! remain |! joined |! only |! at |! the |! tips |! of |! the |! chromatids Last |! stage |! of |! meiotic |! prophase |! I Ends |! with |! the |! breakdown |! of |! the |! nuclear |! membrane |! and |! migration |! of |! chromosomes |! from |! the |! metaphase |! plate Nondisjunction |! of |! homologous |! chromosomes |! in |! meiosis |! I |! - |! Correct |! answer |! ✔All |! gametes |! will |! be |! abnormal |! or |! aneuploid
Have |! N-cadherins |! and |! a |! carbohydrate |! receptor |! on |! their |! surface |! that |! binds |! to |! galactosyltransferase |! proteins |! on |! the |! spermatogenic |! cells Leydig |! cells |! - |! Correct |! answer |! ✔Develop |! from |! interstitial |! mesenchymal |! cells Hormone |! producing |! cells |! - |! secrete |! testosterone |! and |! other |! steroids Look |! like |! little |! clusters |! of |! grapes Spermatogonia |! - |! Correct |! answer |! ✔Stem |! cells |! in |! the |! testis, |! also |! called |! type |! As |! spermatogonia |! or |! spermatogonial |! stem |! cells Small |! cells |! with |! little |! cytoplasm Have |! ovoid |! nuclei Found |! next |! to |! the |! basement |! membrane |! of |! the |! sex |! cords |! and |! seminiferous |! tubules Quiescent |! until |! sexual |! maturity Spermatogonia |! are |! stem |! cells |! - |! Correct |! answer |! ✔Can |! divide |! asymmetrically |! by |! mitosis Produce |! 2 |! more |! spermatogonial |! stem |! cells |! - |! self |! renewal Produce |! 2 |! type |! A1 |! spermatogonia, |! these |! cells |! will |! ultimately |! differentiate |! into |! spermatozoa Incomplete |! cytokinesis Incomplete |! Cytokinesis |! - |! Correct |! answer |! ✔During |! spermatogonial |! mitotic |! divisions, |! cytokinesis |! is |! incomplete |! and |! there |! are |! cytoplasmic |! bridges |! between |! the |! cells
Allows |! for |! communication |! by |! movement |! of |! molecules |! through |! the |! bridges |! - |! leads |! to |! synchronous |! maturation Spermatogenesis |! - |! Correct |! answer |! ✔Spermatogonial |! stem |! cells |! divide |! mitotically |! - |! become |! type |! B |! spermatogonia Type |! B |! spermatogonium |! -Committed |! cell, |! Precursor |! of |! the |! Spermatocytes Divide |! to |! form |! primary |! spermatocytes |! - |! last |! mitotic |! division Primary |! spermatocytes |! complete |! meiosis |! I |! - |! are |! now |! secondary |! spermatocytes Completion |! of |! meiosis |! II |! - |! known |! as |! round |! spermatids This |! is |! the |! end |! of |! spermatogenesis |! - |! next |! step |! is |! spermiogenesis Signals |! regulate |! the |! spermatogonium-spermatocyte |! transition |! - |! Correct |! answer |! ✔Mitosis-Meiosis |! switch |! is |! regulated |! by |! the |! opposing |! actions |! of |! the |! SCF |! and |! GDNF Spermatic |! cells |! express |! receptors |! for |! stem |! cell |! factor |! (SCF) |! which |! is |! secreted |! from |! Sertoli |! cells High |! levels |! of |! SCF |! promotes |! meiosis Sertoli |! cells |! also |! secrete |! Glial |! Cell |! Derived |! Neurotrophic |! Factor |! (GDNF) GDNF |! expression |! is |! up-regulated |! by |! follicle |! stimulating |! hormone |! (FSH) |! from |! pituitary-endocrine |! signaling Low |! levels |! of |! GDNF |! - |! meiosis |! is |! favored High |! levels |! of |! GDNF |! - |! mitosis |! is |! favored Spermiogenesis |! - |! Correct |! answer |! ✔Haploid |! spermatid |! is |! round |! and |! unflagellated
-Leydig |! cells |! - |! Correct |! answer |! ✔Spermiogenesis |! - |! the |! maturation |! of |! the |! spermatozoa A |! young |! man |! was |! given |! a |! chemotherapy |! drug |! that |! caused |! Sertoli |! cells |! to |! die. |! Which |! of |! the |! following |! is |! most |! likely |! to |! result? -Defective |! spermatogenesis, |! normal |! spermiogenesis -Loss |! of |! all |! spermatic |! cells -Low |! testosterone |! levels |! resulting |! in |! reduced |! spermatogenesis -Normal |! spermatogenesis, |! defective |! spermiogenesis |! - |! Correct |! answer |! ✔Loss |! of |! all |! spermatic |! cells Which |! of |! the |! following |! is |! the |! product |! of |! meiosis |! during |! spermatogenesis? -Haploid |! round |! spermatid -Mature |! spermatozoa -Type |! B |! spermatogonium -Spermatogonial |! stem |! cell |! or |! Type |! A |! spermatogonium |! - |! Correct |! answer |! ✔Haploid |! round |! spermatid Ovarian |! cycle |! - |! Correct |! answer |! ✔Maturation |! and |! ovulation |! of |! the |! oocyte |! within |! the |! ovary Uterine |! cycle |! - |! Correct |! answer |! ✔Provide |! appropriate |! environment |! for |! developing |! embryo
Folliculogenesis |! - |! Correct |! answer |! ✔Oocytes |! are |! halted |! at |! diplotene |! of |! meiosis |! I |! right |! before |! birth-remain |! in |! this |! state |! until |! sexual |! maturity Primary |! function |! of |! the |! ovarian |! phase |! in |! mammals |! is |! oocyte |! maturation Complex |! process |! that |! involves |! the |! differentiation |! of |! the |! granulosa |! cells |! and |! resumption |! of |! meiosis End |! result |! is |! complex |! structure |! up |! to |! 20 |! mm |! in |! size |! with |! an |! oocyte |! metaphase |! II |! of |! meiosis Meiosis |! in |! oocytes |! - |! Correct |! answer |! ✔Results |! in |! a |! single |! haploid |! germ |! cell 2N |! oocyte |! stem |! cells |! -> |! Mitosis |! during |! embryonic |! development |! produces |! primary |! oocytes-> |! primary |! oocytes |! enters |! meiosis-> |! 4N |! oocytes |! arrested |! in |! prophase |! I |! of |! meiosis-> |! for |! each |! ovarian |! cycle, |! one |! primary |! oocyte |! resumes |! active |! meiosis-> |! oocyte |! passes |! through |! meiosis |! I, |! arrests |! at |! metaphase |! II |! of |! meiosis |! II |! which |! is |! ovulation |! -> |! 2N |! arrested |! egg |! will |! degenerate |! unless |! fertilized |! (2N |! first |! polar |! body |! degenerates) |! -> |! fertilization |! by |! 1N |! sperm |! -> |! 1N |! male |! pronucleus |! fertilizes |! 1N |! egg, |! forms |! zygote |! and |! develops |! into |! an |! embryo |! while |! second |! polar |! body |! (1N) |! degenerates Female |! oogenesis |! - |! Correct |! answer |! ✔Meiosis |! initiated |! once |! in |! a |! finite |! population |! of |! cells One |! gamete |! produced |! per |! meiosis Completion |! of |! meiosis |! delayed |! for |! months |! or |! years Meiosis |! arrested |! at |! first |! meiotic |! prophase |! and |! reinitiated |! in |! a |! smaller |! population |! of |! cells Differentiation |! of |! gamete |! occurs |! while |! diploid, |! in |! first |! meiotic |! prophase
-Four |! haploid |! germ |! cells |! - |! Correct |! answer |! ✔One |! haploid |! germ |! cell |! and |! one |! to |! two |! polar |! bodies In |! the |! ovary, |! oocytes |! are |! held |! at |! diplotene |! of |! meiosis |! I |! at |! birth. |! How |! is |! the |! diplotene |! block |! released? |! - |! Correct |! answer |! ✔Progesterone |! activates |! c-Mos, |! which |! phosphorylates |! maturation |! promotion |! factor |! (MPF). When |! do |! mammalian |! oocytes |! complete |! meiosis? |! - |! Correct |! answer |! ✔After |! fertilization Follicle |! stimulating |! hormone |! (FSH) |! stimulate |! the |! ______ |! to |! _______ |! and |! secrete |! ______. |! Fill |! in |! the |! blanks |! - |! Correct |! answer |! ✔Granulosa |! cells, |! proliferate, |! estrogen Basic |! steps |! in |! sea |! urchin |! fertilization |! - |! Correct |! answer |! ✔ 1 |! - |! chemoattraction |! of |! sperm |! to |! egg |! by |! soluble |! molecules |! secreted |! by |! the |! egg 2 |! - |! exocytosis |! of |! acrosomal |! vesicle |! to |! release |! its |! enzymes 3 |! - |! binding |! of |! sperm |! to |! egg 4 |! - |! egg |! activation 5 |! - |! passage |! of |! sperm |! through |! extracellular |! envelope 6 |! - |! fusion |! of |! egg |! and |! sperm |! cell |! membranes Sperm |! chemoattraction |! - |! Correct |! answer |! ✔Many |! species |! this |! is |! accomplished |! through |! chemotaxis Resact |! - |! 14 |! amino |! acid |! protein |! isolated |! from |! egg |! jelly |! of |! sea |! urchin
Diffuses |! in |! seawater |! and |! has |! profound |! effect |! at |! very |! low |! concentrations Resact |! induces |! chemotaxis |! in |! sperm |! - |! Correct |! answer |! ✔In |! the |! ocean, |! sperm |! enter |! the |! RESACT |! gradient |! surrounding |! the |! egg |! and |! initiate |! turning |! through |! asymmetric |! flagellar |! waveforms. |! As |! a |! result, |! sperm |! reorient |! towards |! the |! source |! of |! the |! gradient |! and |! are |! guided |! to |! the |! egg Resact |! - |! Correct |! answer |! ✔Released |! by |! the |! egg |! creating |! a |! concentration |! gradient Small |! protein |! - |! only |! 14 |! amino |! acids Recruits |! sperm |! in |! species |! specific |! manner Activates |! sperm |! - |! causes |! increase |! in |! mitochondrial |! respiration |! and |! sperm |! motility Causes |! directed |! swimming |! of |! sperm |! up |! the |! resact |! gradient Molecular |! events |! in |! sea |! urchin |! sperm |! chemotaxis |! - |! Correct |! answer |! ✔Resact |! binds |! and |! activates |! a |! receptor |! guanylyl |! cyclase Causes |! increase |! in |! intracellular |! cGMP |! and |! induces |! the |! opening |! of |! a |! calcium |! (Ca) |! channel Increased |! intracellular |! Ca |! levels |! then |! initiates |! increased |! swimming |! speed |! and |! movement |! towards |! the |! egg Acrosomal |! reaction |! - |! sea |! urchins |! - |! Correct |! answer |! ✔Initiated |! by |! interaction |! with |! specific |! egg |! jelly |! carbohydrates Egg |! jelly |! carbohydrates |! bind |! to |! receptors |! on |! sperm |! membrane |! above |! acrosomal |! vesicle
chemoattractant |! molecule |! will |! bind |! to |! receptors |! on |! the |! sperm |! cell |! membrane. The |! diagram |! above |! describes |! an |! experiment |! done |! with |! 2 |! species |! of |! sea |! urchin. |! Researchers |! removed |! the |! jelly |! coat |! from |! the |! eggs |! and |! incubated |! them |! with |! bindin |! proteins |! from |! each |! species |! as |! diagrammed. |! Which |! of |! the |! following |! statements |! correctly |! interprets |! the |! data? |! - |! Correct |! answer |! ✔Bindin |! binds |! in |! a |! species |! specific |! manner |! to |! eggs. |! The |! bindin |! molecules |! from |! one |! species |! will |! not |! cause |! agglutination |! of |! the |! eggs |! of |! another. Sea |! urchins |! release |! gametes |! into |! the |! ocean. |! Which |! of |! the |! following |! is |! a |! strategy |! employed |! to |! direct |! sperm |! to |! eggs? -Secretion |! of |! follicular |! fluid |! by |! the |! oocyte -Secretion |! of |! resact |! by |! sperm -Binding |! of |! ZP -Secretion |! of |! resact |! by |! the |! oocyte |! - |! Correct |! answer |! ✔Secretion |! of |! resact |! by |! the |! oocyte. |! Resact |! acts |! as |! a |! chemoattractant |! to |! direct |! sperm |! motility |! towards |! the |! oocyte. The |! acrosome |! reaction |! _____ |! - |! Correct |! answer |! ✔Releases |! enzymes |! necessary |! for |! penetrating |! the |! jelly |! layer. |! Allows |! for |! a |! sperm |! to |! penetrate |! the |! jelly |! layer |! by |! causing |! the |! release |! of |! enzymes |! which |! degrade |! the |! jelly |! layer |! around |! the |! egg. Basic |! steps |! in |! mammalian |! fertilization |! - |! Correct |! answer |! ✔1. |! chemoattraction |! of |! sperm |! by |! soluble |! molecules |! secreted |! by |! the |! egg
- |! capacitation
- |! binding |! to |! the |! zona |! pellucida
- |! acrosome |! reaction
- |! passage |! of |! sperm |! through |! the |! zona |! pellucida
- |! fusion |! with |! the |! ovum |! membrane
- |! egg |! activation Sperm |! attraction |! in |! mammals |! - |! Correct |! answer |! ✔Follicular |! fluid |! taken |! from |! preovulatory |! follicles |! and |! added |! to |! sperm |! caused:
- |! change |! in |! speed
- |! change |! in |! direction |! towards |! the |! follicular |! fluid
- |! other |! compounds |! had |! no |! effect
- |! only |! eggs |! that |! are |! fertilizable |! produced |! this |! compound |! in |! follicular |! fluid |! and |! only |! capacitated |! sperm |! respond Thermal |! gradient |! along |! the |! oviduct |! also |! provides |! directional |! cue Translocation |! of |! sperm |! into |! oviduct |! - |! mammal |! specific |! - |! Correct |! answer |! ✔Sperm |! motility |! - |! pre-capacitation |! this |! will |! get |! the |! sperm |! into |! the |! uterus |! - |! in |! humans |! motility |! is |! defined |! as |! forward |! progression |! of |! at |! least |! 25 |! microns/s Uterine |! contractions |! - |! sperm |! are |! found |! in |! oviducts |! within |! 30 |! minutes |! - |! too |! fast |! for |! swimming |! speed. |! Contractions |! are |! critical |! for |! entry |! to |! oviduct. Directional |! cues |! - |! from |! chemical |! gradients Sperm |! rheotaxis |! - |! sense |! flow |! of |! liquid |! from |! oviduct |! to |! uterus |! and |! swim |! against |! it Capacitation |! - |! must |! happen |! - |! increases |! speed |! and |! directionsal |! swimming
Zona |! pellucida |! - |! Correct |! answer |! ✔Glycoprotein |! matrix, |! secreted |! by |! the |! oocyte Rigid, |! species |! specific Zp1 |! - |! ZP3 |! in |! mice, ZP1-ZP4 |! in |! humans Binds |! sperm Transgenic |! mouse |! eggs |! that |! express |! 1 |! human |! ZP |! protein |! - |! what |! does |! sperm |! bind? |! - |! Correct |! answer |! ✔Mouse |! eggs |! that |! are |! transgenic |! for |! 1 |! human |! ZP |! protein |! only |! (humans |! have |! 1 |! extra-ZP4) Isolated |! transgenic |! oocytes |! and |! mixed |! with |! human |! sperm ZP2 |! oocyte |! has |! sperm |! attached Sperm |! binding |! in |! mammals |! - |! Correct |! answer |! ✔Oocytes |! encounter |! sperm |! that |! are
- |! acrosome |! intact-pathway |! 2 |! or
- |! acrosome |! reacted |! - |! pathway |! 1 Mammalian |! Acrosome |! reaction |! - |! Correct |! answer |! ✔1. |! Izumo |! - |! protein |! found |! in |! the |! acrosome |! vesicle |! membrane
- |! Acrosome |! reaction |! exposes |! inner |! acrosomal |! membrane |! to |! environment- equatorial |! region |! - |! will |! actually |! contact |! oocyte |! membrane
- |! Izumo |! redistributes |! along |! sperm |! head
- |! Izumo |! binds |! to |! oocyte |! protein |! Juno/CD
- |! Sperm |! and |! egg |! membranes |! fuse |! and |! sperm |! enters |! oocyte
- |! Male |! nucleus |! stimulates |! oocyte-Ca++ |! oscillations |! and |! activates |! blocks |! to |! polyspermy Fast |! Block |! to |! polyspermy |! - |! Correct |! answer |! ✔Change |! in |! egg |! membrane |! potential Makes |! the |! ionic |! concentration |! of |! the |! egg |! very |! different |! from |! surroundings, |! especially |! for |! Na+ |! and |! K+ |! ions Movement |! of |! Na+ |! into |! egg |! after |! sperm |! penetration |! block |! fusion |! by |! other |! sperm Humans |! no |! detectable |! fast |! block Cortical |! granule |! reaction |! - |! slow |! block |! to |! polyspermy |! - |! Correct |! answer |! ✔Influx |! of |! Ca2+, |! cortical |! granules |! fuse |! with |! membrane |! after |! sperm |! entry |! and |! release |! contents |! - |! cortical |! granule |! exocytosis Cortical |! granules |! contain |! enzymes |! serine |! proteases |! - |! digests |! proteins |! away, |! such |! as |! ZP2, |! that |! bind |! sperm. N-acetylglucosaminidase |! removes |! glycosylation |! from |! ZP3-blocks |! sperm |! binding H2o2 |! hardens |! and |! crosslinks |! proteins |! - |! creates |! the |! fertilization |! envelope Fusion |! of |! genetic |! material: |! syngamy |! - |! Correct |! answer |! ✔-fertilization |! allows |! for |! the |! formation |! of |! genetically |! unique |! individuals -occurs |! by |! fusion |! of |! egg |! and |! sperm |! nuclei |! forming |! a |! new |! diploid |! cell -centrosome |! from |! male |! pronucleus |! creates |! asters, |! microtubles |! join |! the |! pronuclei |! and |! they |! migrate |! towards |! each |! other |! in |! the |! center |! of |! the |! fertilized |! egg -chromosomes |! condense |! on |! a |! common |! spindle |! (Syngamy)
Mammalian |! fertilization |! must |! occur_____ |! - |! Correct |! answer |! ✔In |! the |! infundibulum |! of |! the |! oviduct |! or |! fallopian |! tubes A |! change |! in |! egg |! membrane |! potential |! due |! to |! an |! influx |! of |! Na+ |! ions |! is |! part |! of |! which |! of |! the |! following? |! - |! Correct |! answer |! ✔The |! fast |! block |! to |! polyspermy. Implantation |! determines: |! - |! Correct |! answer |! ✔ICM |! orientation |! to |! set |! up |! the |! proximal-distal |! (dorsal-ventral) |! axis Which |! of |! the |! following |! cell |! types |! is |! formed |! from |! epiblast |! cells |! that |! migrate |! through |! the |! primitive |! streak? -ectoderm -primary |! hypoblast -mesoderm -trophoblst |! - |! Correct |! answer |! ✔mesoderm. |! cells |! that |! migrate |! through |! the |! primitive |! streak |! become |! mesoderm All |! the |! cells |! of |! the |! embryo |! proper |! (all |! the |! cells |! in |! your |! body |! now) |! derive |! from |! which |! of |! the |! following |! structures? |! - |! Correct |! answer |! ✔Epiblast The |! anterior |! visceral |! endoderm |! is |! important |! in |! axis |! formation |! and |! determines |! which |! end |! of |! the |! embryo? |! - |! Correct |! answer |! ✔Rostral.
