TLS Online TPP Program

#Question id: 7303


The ‘quartet model’ explains how the protein products of the ABCE-function genes might interact to control floral organ identity. Following statements are based on this model. Which one of them is incorrect?

#Unit 5. Developmental Biology
  1. There are four combinations of floral MADS-box proteins. SEP proteins may form heterodimers with A (AP1) and B (AP3/ PI) proteins (for petals), B (AP3/PI) and C(AG) proteins (for stamens), and C (AG) protein (for carpels).
  2. All these genes, with the exception of AP2 (and its homologues), are MADS-box genes, a broad family of eukaryotic genes that encode transcription factors containing a highly conserved DNA-binding domain (MADS domain).
  3. The protein quartets are transcription factors and may function by binding to the promoter regions of target genes.
  4. According to the model, one dimer of each tetramer recognize two different sites on the same DNA strand, thus bringing these areas into proximity via DNA-bending.

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TLS Online TPP Program

#Question id: 5680

#Unit 5. Developmental Biology

In vitro model of species-specific binding shows in figure. Add the bindin particles to a plastic well containing a suspension of eggs. After 2–5 minutes of gentle shaking, the wells were photographed.

 According to this figure, which of the following conclusion correctly define the phenomenon of species specificity?

TLS Online TPP Program

#Question id: 5681

#Unit 5. Developmental Biology

What is the arrangement of microtubules in sperm flagellum?

TLS Online TPP Program

#Question id: 5682

#Unit 5. Developmental Biology

During prevention of polyspermy in sea urchin the shift from ___1___ to __2____is the result of a small influx of Na+ into the egg through newly opened sodium channels. Sperm cannot fuse with egg cell membranes that have a ___3___ resting potential, so the shift means that no more sperm can fuse to the egg.

TLS Online TPP Program

#Question id: 5683

#Unit 5. Developmental Biology

There may be an important connection between sperm translocation and capacitation. Which of the following option is correct explanation of above statement?

TLS Online TPP Program

#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.

TLS Online TPP Program

#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?