Vaccination is only effective in persons who have previously produced memory cells as a result of a mild case of polio. All vaccinated persons have memory cells that recognize polio virus antigens. Exposure of vaccinated persons to polio virus will induce a response from the specific memory cells that recognize polio virus antigens. Memory cells that recognize polio virus antigens can survive for decades in the body of a person vaccinated against polio. An antigen is a. any substance capable of activating virgin lymphocytes.
Eukaryotic genomes consist of a. a single circular chromosome.
The primary function of meiosis is to a. reduce the chromosome number to produce haploid gametes. The physical position of a particular gene along a chromosome is known as its a. allele. Gregor Mendel was a contemporary of a. Charles Darwin. Genes are said to be linked a. when their loci are on the same chromosome. When our defenses against disease are overwhelmed by infection, drug treatments can reduce the infection to levels that permit our own immune responses to cure us.