Questions

Microscopes are of three types. They are :

1) Optical microscopes

2) Electron microscopes

3) Scanning tunneling microscopes

Scanning tunneling microscopes are the microscopes that are used to view metal surfaces.

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.

At the synapse between two neurons, electrical signals are converted into chemical signals. A synapse is the gap between the two neurons.

Study of Life in outer space or search of life external to Earth is known as Exobiology.