Sickle cell anemia is a disease in which red blood cells become irregularly shaped. The disease is caused by the presence of an incorrect amino acid
in a certain protein. The disease most likely occurred due to an altered
sequence of nitrogenous bases in the-*
-original DNA in the nucleus
-transcribed mRNA strand
-tRNA on the ribosome
-complementary DNA strands

How are mutations continually being generated in a population (what are some of the causes of mutatuions? ) explain

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

Which nucleotide component contains nitrogen