Questions

A RNA copy of a DNA gene is called as messenger RNA or mRNA. mRna is used in translation because information is translated from one language (nucleotides) into another (amino acids).

Hence, mRNA is used to transfer genetic information by a cell.

Parvovirus B19 causes severe anemia because it preferentially infects erythrocyte precursors.

a. Parvovirus B19 binds preferentially to the erythrocyte blood group P antigen on erythroid precursor cells.

Answers B, C, D are incorrect:

b. after entry the single-stranded viral DNA genome is transported to the cell nucleus where the host DNA polymerase synthesizes the complimentary DNA strand.

c. Parvovirus B19 infection can be diagnosed by direct detection of viral DNA not RNA.

d. the fetus of a seropositive mother is protected from infection by maternal circulating antibodies.

Core of earth is also known as Barysphere.

Phosphorescence is a phenomenon associated with an algal division called euglenophytes. 

Phosphorescence is a phenomenon when an object is capable of releasing photons of light at a longer wavelength in response to absorbing light of a shorter wavelength. The object releasing the light only releases the light after some time has passed since it absorbed the light of a short wavelength.

Euglenophytes are single-celled plant-like protists that have no cell wall.

Five basic tastes are :

salty,

sweet,

bitter,

sour, and

umami.

The taste receptors are located all over in the mouth around paillae structures.