The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes. One explanation for the effect of overexpression of the cytoplasmic domain of the integrin beta subunit is that this domain normally functions to bind a cytoplasmic factor necessary for integrin function. Which of the following would be the most informative experiment to identify the cytoplasmic factor?

#Question id: 10255

#Unit 6. System Physiology – Plant

In sucrose synthase combines sucrose with UDP to produce fructose and UDP-glucose in the cytosol. What is the function of UDP-glucose pyrophosphorylase?

#Question id: 12027

#Unit 7. System Physiology – Animal

#Question id: 23340

#General Aptitude

#Question id: 5686

#Unit 5. Developmental Biology

Following statements are regarding to double fertilization in angiosperms.

A. One sperm cell fuses with the egg cell to produce the zygote that will develop into the new embryonic plant.

B. The second sperm cell fuses with the usually binucleate central cell, giving rise to the

endosperm, the tissue that nourishes the developing embryo. This second event is not “true” fertilization in the sense of male and female gametes undergoing fusion.

C. The second sperm cell fuses with the usually binucleate central cell, giving rise to the

endosperm, the tissue that nourishes the developing embryo. This second event is “true” fertilization in the sense of male and female gametes undergoing fusion.

D. During fertilization in angiosperm, when the sperm cells are released, the egg undergoes a flux of Ca2+. Then, chemicals released from the egg appear to make the sperm competent for cell fusion.

Which of the following statements are true?

#Question id: 19889

#Unit 12. Applied Biology