Which choice below shows a correct order of events during development? Gastrula, blastula, neural tube closure, and primary vesicle formation. Blastula, neuroepithelial cell proliferation, axonogenesis and synapse maturation. O Gastrula, dendritogenesis, neural tube closure and synapse formation. O Neural tube closure, notochord formation, dendritogenesis and synapse formation. Axonogenesis, neuronal migration, synapse maturation, synaptic specialization

what evolutionary advantages does the amniotic egg have? explain how each component of the egg plays a role in survival of the embryo

7. name the stage of development represented in the photo

tion 7 of 11 Which of the structures highlighted in the image contains a transverse flagellum? Macmillan Learning 2 C Search or type URL A b MacBook Pro & + tv

Background: The slow block to polyspermy involves a permanent modification of the egg surface, usually through exocytosis of the cortical granules. In the 1970s, Dave Epel carried out experiments that led to the conclusion that a Ca2+ rise in the egg is both necessary and sufficient to trigger cortical granule exoctyosis (CGE).       Experiment (c) – Dr. Epel injects a calcium chelator (called EGTA; chelators act as specific “sinks” or “magnets” for ions) into unfertilized eggs and then adds sperm. The sperm bind and fuse with the eggs, but no CGE occurs.   For the experiment above, describe it as correlation, loss-of-function or gain-of function. Then, indicate the predicted result.

Which of the following is an illustration of permissive interaction?   -When implanted in the newt embryo, the frog oral ectoderm can only differentiate into frog derivatives and will not differentiate into newt derivatives.   -Contact with the appropriate extracellular matrix is sufficient for cells to express differentiation-specific genes.   -An inducing signal from the optic vesicle is necessary for new gene expression in the lens ectoderm.   The epidermis signals the underlying dermis to create condensations and the dermal condensations then signal the epidermis to form specific cutaneous structures.   Wing epidermal epithelium produces wing feather when exposed to wing dermal mesenchyme, but will produce scales and claw when exposed to foot dermal mesenchyme.

6)From the menu on the left on Virtual Urchin, click on "embryogenesis to hatching". This will display a video of sea urchin development. Photos of key stages taken with a scanning electron microscope (SEM) are shown next to the video. In addition to watching the video by clicking the play button, you can use the slider at the bottom to move through the stages step by step. Doing this will allow you watch how cell division increases the number of cells from the initial zygote. You'll notice that these divisions start off dividing cells evenly, but at a certain point, there are some smaller cells created. These smaller cells will play very important roles in the later development stages of the urchin, so their creation is a key milestone.   Which round of cell division is uneven? (hint: the SEM images will be helpful) a)First b)Second c)Third d)Fourth e)Fifth

Q12

Which of the following structures of a mammalian embryo can be used to produce embryonic stem cells by simple maintenance in culture? (Check all that apply.) A Epiblast Primitive endoderm Trophectoderm Blastocoel Inner cell mass

10 @ 2 # 3 Question 6 During the start of the third week of development, numerous lacunae appear in the primary extraembryonic mesodermal reticulum to form the future chorionic cavity. Between which two layers does this mesodermal layer initially appear? Select one: O a. Syncytiotrophoblast and cytotrophoblast @ O O b. Exocolomic (Heuser's) membrane and cytotrophoblast. c. Syncytiotrophoblast and extracoelomic (Heuser's) membrane d. Epiblast and hypoblast O e. Syncytiotrophoblast and endometrium Previous page Not yet answered $ 4 24 Marked out of 1,00 % 5 4 A 6 P Flag question MacBook Pro <44) & 7 * x 8 ( 9 c -0 D - { + 11 } Next page delete