Many mouse genes are “tissue-specific,” that is, they are present throughout the body but are expressed in only one of the animal’s many tissue types. (Other mouse genes are expressed throughout the body, or in multiple tissues.) Geneticists can study the regulation of a mouse gene by fusing the gene’s promoter region to the LacZ coding sequence and injecting the construct to create a transgenic mouse. Fusion of the mouse amylase promoter to LacZ yielded a Pamylase-LacZ construct.              

Mice heterozygous for the resulting Pamylase-LacZ  transgene displayed the LacZ expression exclusively in the pancreas. Would you expect homozygotes for the transgene to also display LacZ expression in the pancreas?.

#Question id: 5684

#Unit 5. Developmental Biology

Capacitated mammalian sperm can sense thermal differences as small as 0.014ºC over a millimeter and tend to migrate toward the higher temperature. This ability to sense temperature difference and preferentially swim from cooler to warmer sites is called as _____1___ found only in ______2____ sperm.

#Question id: 5685

#Unit 5. Developmental Biology

Human sperm are allowed to fertilize ova having non- functional ovastacin. The following possibilities may be of significance in the fusion of these gametes:

A.        The sperms will not fertilize ova.

B.        The sperms will bind and penetrate the zona pellucida but will not be able to fuse with ovum membrane.

C.        ZP2 will not be clipped by cortical granule protease.

D.        CD9 protein of egg membrane microvilli will not be able to interact sperm membrane proteins in the absence of ovastacin.

E.         Polyspermy may occur frequently.

Which combination of statements represent the outcome of the above event?

#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: 5687

#Unit 8. Inheritance Biology

The error in meiosis that produces a 47,XYY karyotype is best  described by

#Question id: 5688

#Unit 8. Inheritance Biology

Which of the following are not cause of aneuploidy

#Question id: 5689

#Unit 8. Inheritance Biology

What kind of aneuploidy gamete will be generated if meiotic nondisjuction in second division (n represent haploid number of chromosome )