#Question id: 5139
#Unit 5. Developmental Biology
There are two broad categories of receptors that activate tyrosine kinases: (1) those in which the tyrosine kinase enzyme is an intrinsic part of the receptor’s polypeptide chain, called the_________ and (2) those, in which the receptor and kinase are separate polypeptides, encoded by different genes, yet are bound tightly together, called the __________.
#Question id: 5140
#Unit 5. Developmental Biology
Following statements regarding to the Ectodermal competence and the ability to respond to the optic vesicle inducer in Xenopus.
A. The optic vesicle is able to induce lens formation in the posterior portion of the ectoderm but not in the anterior portion.
B. If the optic vesicle is removed, the surface ectoderm forms either an abnormal lens or no lens at all.
C. Only head ectoderm is competent to respond to the signals from the optic vesicle by producing a lens.
D. The head ectoderm appears to secrete two paracrine factors BMP 4 and FGF8, which involves in the activation of lens-specific genes such as crystallin.
Which of the following combination is incorrect?
#Question id: 5141
#Unit 5. Developmental Biology
Which of the following statement not describe the concept of morphogenetic gradient?
#Question id: 5142
#Unit 5. Developmental Biology
The D set of blastomeres is the “organizer” of snail embryos. Experiments have demonstrated that the non-diffusible polar lobe [cortical] cytoplasm that is localized to the D blastomere is extremely important in normal molluscan development. Which of the following is incorrect?
#Question id: 5143
#Unit 5. Developmental Biology
Select the correct sequence of events in photoreceptor induction in drosophila.
A. Morphogenetic furrows moves across eye disc
B. Eyeless gene expression
C. R8 photoreceptor cells develop
D. R7 photoreceptor cells develop
#Question id: 5144
#Unit 5. Developmental Biology
Following statements regarding to noncanonical wnt pathways.
A. The planar cell polarity, or PCP, pathway functions to regulate the actin and microtubule cytoskeleton, thus influencing cell shape, and often results in bipolar protrusive behaviors necessary for a cell to migrate.
B. Wnts (such as Wnt5a and Wnt11) can activate Disheveled by binding to a different receptor (Frizzled paired with Ror instead of Lrp5), and this Ror receptor complex phosphorylates Disheveled in a way that allows it to interact with Rho GTPases.
C. Wnt/PCP signaling through cytoskeleton control can direct cells to divide in the different plane ( forming upper and lower tissue compartments) and to move within that different plane.
D. the Wnt/calcium pathway leads to the release of calcium stored within cells, and this released calcium acts as an important secondary messenger to activates a phospholipase (PLC) whose enzyme activities release a compound that in turn releases calcium ions from the cytosol.
Which of the following is incorrect?