In: Biology
The bending of the neural plate involves all of the following, except?
a. Formation of hinge regions |
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b. Cell wedging/cell shape changes |
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c. High BMP signaling |
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d. Medial forces from the surface ectoderm |
ANSWER : The correct alternative is (c) High BMP signalling.
REASON- . It has been seen some moleules like noggin, chordin, follistatin(in amphibians) inhibit the BMP signalling i.e more specifically block the Bone Morphogenic protein -4 (BMP-4) which induces neural tube forrmation,supressing the epidermal exprression.
All the the other three alternatives are events ocuuring in the process of neural tube bending.
(a) Formation of hinge regions- The events of bending of neural plate involves the formation of hinges , whereby the midline of the neural plate is called median hinge point i.e MHP.
(b) Cell wedging/Cell shape changes- The cells present in median hinge point i.e MHP will begin to change shape , they will in turn decrease in height and become wedge-shaped. This process is called cell wedging.
(c) Medial forces from the surface of ectoderm- The extrinsic medial forces pushes the surface ectoderm towards the midline , so that the bending of neural tube occurs.