Bio 348 Exam 2 with complete solutions.

Cell layers ectoderm (skin and neural plate) Mesoderm (muscle, connective tissues, vascular system) Endoderm (gut tube, lungs, liver) Neurulation Formation of the vertebrate nervous system, CNS is dervied from epithelial cells Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:00 / 0:15 Full screen Brainpower Read More The three different vesicles Proencephalon (turns into the retina), mesencephalon, rhombencephalon Inductive factors signaling molecules secreted by cells that instruct neighboring cells to adopt specific fate Cell surface signaling mediated by cell surface receptors that trigger specific gene expression programs that instruct cells to adopt a specific fate Spemann's organizer group of cells capable of instructing neighboring cells to adopt specific fate, SUFFICIENT for neural plate formation it is cell-cell contact dependent NOT NECESSARY, cells naturally go neural fate, need signal to block neural fate Bone Morphogenetic Proteins (BMPs) produced by ectoderm, neurl repressors, organizer produces inhibitory signals that antagonize BMP signaling Notch signaling in fruit flies mediates neural vs epidermal cell fate choice, starts balance, stochastic event leads to delta expression, results in Notch activation and repressed pro neural genes (notch expression blocks specification of NPCs) Neural fate is default, notch is required to inhibit it Secreted molecules pattern the CNS rostral/caudal patterning of early neural plate is secreted by mesoderm and endoderm Wnt activty drives expression of TF's that drive specification determine anterior and posterior sides (anterior receives inhibited levels from endoderm, posterior receives high levels of wnt from mesoderm) Signaling Center boundary between low and high Wnt activity Isthmus midbrain (MB)/hindbrain (HB) boundary Boundaries Otx2 determines forebrain/midbrain Gbx2 determines hindbrain Engrailed necessary and sufficient for development of hindbrain structures, highly conserved because it