biol131 hw9 kyle han

Free Response 1 (5 points) : Diagram the correct primary induction process in frogs making sure to include the blastocoel, ventral lip, yolk plug, dorsal lip, and “neuralizing” factors. Is primary induction in the formation of the neural plate associated with positive or negative factors? Explain. Free Response 2 (5 points) :In class we learned about a protein called Sonic hedgehog (Shh) and its relation with the function and the development of the neural tube. What tissue/structur produces this protein? What do the release of this protein and BMP lead to? What does the Shh activate and how is this related to the motor neuron formation? 2. Sonic hedgehog (Shh) is a protein that is produced by the notochord, a structure that lies beneath the neural tube during early embryonic development. The notochord is a rod-like structure that is important for patterning the developing embryo. The release of Shh and BMP (bone morphogenetic protein) signaling molecules are critical for the proper development of the neural tube. Shh signaling induces the ventral (bottom) side of the neural tube to develop into motor neurons, while BMP signaling promotes the development of dorsal (top) neural tube cells into interneurons and sensory neurons. Shh activates a transcription factor called Gli, which is a key regulator of motor neuron development. Gli induces the expression of specic genes that are required for motor neuron dierentiation and axon growth. Additionally, Shh signaling is important for the development of motor neuron subtypes, which are specialized groups of motor neurons that innervate dierent types of muscles. In summary, Shh is produced by the notochord and its release, along with BMP, is essential for proper neural tube development. Shh signaling induces the development of motor neurons through the activation of Gli, which promotes the expression of genes required for motor neuron dierentiation and subtype specication. A. Release of B. Release of Again positive factors : factors : the lsignal from the sight / a- rides instruction notochord instructs +0 become epidermal , allowing th overlying epithelium -1° the default pa-tnayofaei.ua , development to proceed become neural collapsing bhstruoel heading ⑥ inaction factor least - dorsal tip of factors that neutralise ventral # Yolk pl -8 instructors to become epiderma