CMMB 403 Final Exam with complete solution

CMMB 403 Final Exam with complete solution does the fish organizer and the Nieuwkoop centre have similar functions as their amphibian counterparts? - answeryes they do! at what stage is the xenopus and zebrafish niewkoop centre form? - answerat the late blastula stage (near the end of cleavage) at what stage does the Xenopus and the Zebrafish form it's organizer? - answerat the gastrula stage what is the fish organizer also called? - answerthe embryonic shield Where is the fish Nieuwkoop centre formed? - answeris the yolk syncytial layer below the shield do fish zygotes under cortical rotation? what happens instead? - answerno!! the organizer in fish is not initiated on other side of sperm entry. beta catenin accumulation due to the cells of the yolk syncytial layer beneath the shield what activates the organizer genes in the zebrafish? - answerB-Catenin what marks the dorsal side of the xenopus blastula? what does this help to form? - answernuclear localization of B-Catenin marks dorsal side & helps to form its Nieuwkoop Centre beneath the organizer in the zebrafish late blastula, where is nuclear localization of B-Catenin found? - answerseen in the yolk syncytial layer nuclei beneath the future embryonic shield what is the Vg1 homolog? - answersquint (Nodal-like) what is the siamois ortholog? - answerbozozok (TF genes) what is the homolog of chordin? - answerchordino what does gastrulation occur through in amniote embryos? - answera linear structure called the primitive streak when the cells of the primitive streak ingress, what layer(s) do they form? - answerendoderm and mesoderm (and undergoing EMT) what do the cells form that do not ingress through the primitive streak? - answerectoderm and remain in the epiblast what end of the primitive streak do the cells of hensens node form? - answeranterior end of the primitive streak what do the cells of Hensen's node serve as? and what is it a source of? - answerthe thickening of cells at anterior end of the primitive streak forms the amniote organizer and is a source of cells expressing BMP inhibitors at what point can you determine anterior/posterior axes in an early amniote embryo? - answeras soon as you can see the node what characterizes reptiles, birds and mammals? - answerthe membranes of the amniote egg amniotic animals have 4 extra-embryonic membranes, what are they? - answer1. yolk sac (provides nutrition for the embryo) 2. chorion (gas exchange) 3. allantois (sac for the waste products) 4. amnion (surrounds the embryo and allows development to take place outside of water) whats the big difference in extra-embryonic membranes between amniotic animals and mammals? - answerthe placenta! what do the epiblast cells form that remain close to the streak? - answerneural tissue what do the epiblast cells form that are farther from the streak? - answerepidermis how can you predict what structures particular cells will form? - answerbased on when and where they enter the streak what will the cells entering the streak more anteriorly form? - answermore dorsal structures what will the cells entering the streak first tend to form? how bout later? - answermore anterior structures, cells entering later will form more posterior structures where will the cells enter that form the heart, blood, or kidneys? - answerthrough the middle of the streak where do the cells enter that form the notochord? - answerthrough the anterior of the streak at the node what transformation do cells go through when they ingress through the streak? - answerepithelial to mesenchymal transformati