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31 Cards in this Set
- Front
- Back
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describe the ovarian cycle. |
it repeats every 28 days. hypothalamus releases GnRH releasing FSH and LH. LH surge 1 day before ovulation is what causes the egg to burst out of the follicle. follicle stays and becomes a corpus luteum which plays a role in continuing stimulation of ovarian hormones. if not pregnant, it degrades surge in estrogen causes LH surge. progesterone levels increase in cycle because of corpus luteum. |
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Sperm maturation and transport |
sperm is produced in the testes, it matures in the epididymus. goes up vas deferens into seminal vesicle where fluid is added. then urethra and penis SEVEN UP. |
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sperm structure |
tail end , middle with mito sheath , neck, head with nucleus and acrosome. Acrosome serves to digest layers to get into egg. |
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how is polyspermy prevented? |
one sperm attaches to the zona pellucida which causes changes within the oocyte. a fast block involves rapid electrical depolar. slow block involves calcium release from site of fusion release of poly saccharides (a.k.a. permanent chemical change) also zonal reaction to change sperm receptors preventing further binding. |
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what occurs during the early stages of development? |
sperm and egg fuses, second meosis completes, egg divides, becoming a morula (8 cells) at 2.5 days. divisions continue becoming a blastocyst (trophblasts and inner cell mass) finally implants in uterine wall. |
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What is cleavage? |
repeated mitotic divisions of the cells in the zygote. the morula migrates, and uterine fluid moves into the morula creating a cavity. this is called a blastocyst. |
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how does implantation occur? |
blastocyst becomes sticky, and implants to the endometrium. blastocyst becomes epiblast and hypoblast with a new layer called amniotic cavity. it is surrounded by the amnion. (formed from the inner cell mass). epi and hypo blast forms the embryo the amnion and the trophoblast forms the extra embryonic layers. endometrium capillaries invade tissue. |
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what is gastrulation? |
the embryo becomes 3 layered. there is a formation of a primitive streak which goes longitudonally to the embryo. cells migrate from epiblast out of primitive streak and become meso and endodermal cells. neural plate forms and covers the notochord. |
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what are the three layers made by gastrulation and what do they develop? |
endoderm- gut, liver, lungs mesoderm- skeleton, muscle, kidney, heart, blood. ectoderm- skin, nervous system |
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what is the notochord for? |
it exists only in embryos and it is responsible for patterning the surrounding tissue during development. it secretes proteins that are essential to embryonic development. |
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what do mesenchyme cells do? |
they are responsible for making somites which are precursors to muscle, dermis, and ribs. |
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how does a single cell form a multicellular organism? |
cell proliferation cell specialization cell interaction cell movement |
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what is regulation (in development) and how did Driesch's study of regulation contradict mosaic model? |
regulation is the ability of an embryo to develop normally even when some portions are taken out/rearranged. this contradicted mosaic model which stated that every cell had its own fate and altogether formed functional organism. |
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What is determination? what is regional determination? |
determination is when a cell chooses its particular fate as to what it will be. regional determination is when a cell has markers of position or region in the body that occurs before committing to differentiation. |
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what is induction? |
cells that can secrete signals to neighboring cells creating orderly differences between identical cells. it can become part of a signalling pathway. 2 ways: cell-cell contacts which is short range. or diffusion of molecules through extra cellular medium which is long range. |
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what are different inductive signals? |
diffusion direct contact gap junction. |
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what are morphogenes? |
chemicals whose concentration varies and is involved with pattern formation. ex. high concentration can yield motor neurons but same signal in lower concentration yields just neurons. |
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why do we study vertebrates? |
because certain things can't be studied in humans there are similar sets of developmental stages present. very similar in early developmental stages. |
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Why do we study amphibians like frogs? |
easy to grow in tap water fertilized eggs can be obtained after injection with hGH. eggs can be visualized quick cleavage can do microsurgery without infections useful for knockdown studies |
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Why do we use birds |
similar morphological complexity easy to obtain and observe able to do microsurgery knockdown analysis. |
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Why do we study mice |
short life cycle knockout studies similar in some ways to humans develop in mothers. |
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Why do we study fish like Zebrafish |
short life cycle transparency of embryo mutations and knockdown/transgenic studies possible. |
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why do we study fruit flies? |
can do combo of genetic and microsurgical manipulations short life cycles lots of genetic/transcription factor studies |
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why do we study nematodes? |
suitable for genetic analysis small number of cells transparent embryo easy to disrupt function. |
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what are transgenic studies used for and how do you do it |
it's basically adding info you're trying to see what happens when a gene becomes over expressed. can be done by pronucleus or zygote injection, retroviral gene transfer in embryos |
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What are knock out studies used for and how are they done? |
this is changing info it is the inactivation or disruption or deletion of a gene to try and figure out its role. it is done by homologous recombination of ESC. you can't inject at the pronucleus. |
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What are knock in studies used for and how are they done? |
it is also changing info. it is done by homologous recombination of ESC. you can do exchanges of protein domain or exons or point mutations. |
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how is random gene inactivation done? |
it is gene trapping in ESC |
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how is large scale random mutagenesis done? |
radiation or ENU |
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what is the crisper cast method? |
easiest way to do a genetic manipulation. you use guide RNA with sequences of interest and a protein that will cut the sequence. then you hope a repair mechanism will come and make the necessary changes. it isn't as long of a process as knock out. |
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Why would you use transgenic studies? why would you use KO studies? |
transgenic- for promoter analysis, impact of protein mis-expression, over expression, and mutant expression KO- for basic impact of losing a gene from the genome. |
