Questions

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.

The term facultative anaerobe refers to an organism that which uses oxygen when it is present or grows without oxygen when it is not there.

These are called intrusive igneous rocks because the magma has intruded into pre-exiting rock layers. Types of intrusive igneous rocks are granite and basalt .

A batholith is the largest of the intrusive bodies.

Most known extrasolar planets most resemble to the planet Venus.