Daily NEET MCQ- March 13, 2022 - NEET MCQ

Bacillus thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. These protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to alkaline pH of the gut which solubilize the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of insect.

Metallic crystals consist of metal cations surrounded by a sea of mobile valence electrons. These electrons are capable of moving through the entire crystal. The metallic crystals conduct heat and electricity due to the presence of these mobile electrons in them.

Most unsymmetrical crystal system is triclinic in which all three axes are unequal in length none is perpendicular to another. Triclinic unit cells has the least symmetrical shape of all unit cells. Turquoise is an example of triclinic crystal.

Goblet cells secrete mucus and bicarbonates present in the gastric juice which plays an important role in lubrication and protection of the mucosal epithelium from excoriation by the highly concentrated HCl.

The body is able to differentiate self and nonself and the cell-mediated response is responsible for graft rejection.

Be(OH)₂ amphoteric in nature, since it can react both with acid and base
Be(OH)₂ + 2HCl → BeCl₂ + 2H₂O
Be(OH)₂ + 2NaOH → Na₂ [Be(OH)₄]

Fuse wire has less melting point so when excess current  flows, due to heat produced in it, it melts.

In p-type semiconductor, an intrinsic semiconductor is doped with trivalent impurities, that creates deficiencies of valence electrons called holes which are majority charge carriers.

Rainbow can't be observed when observer faces towards sun.

Red has the longest wavelength among the given options.