Figure 17.5 Which of the following statements about virus structure is true?
- All viruses are encased in a viral membrane.
- The capsomere is made up of small protein subunits called capsids.
- DNA is the genetic material in all viruses.
- Glycoproteins help the virus attach to the host cell.
Figure 17.6 Influenza virus is packaged in a viral envelope, which fuses with the plasma membrane. This way, the virus can exit the host cell without killing it. What advantage does the virus gain by keeping the host cell alive?
Figure 17.17 The Rh antigen is found on Rh-positive red blood cells. An Rh-negative person can usually carry an Rh-positive fetus to term without difficulty. However, having a second Rh-positive fetus may launch an immune attack that causes hemolytic disease of the newborn. Why do you think hemolytic disease is only a problem during the second or subsequent pregnancies?