Houses usually have a light source in every room, but it would be a waste of energy to leave every light on all the time, so there are switches to turn off the lights in rooms that are not in use. sometimes one switch controls several lights in the same room. likewise, prokaryotic cells can turn genes on and off based on environmental factors. sometimes related genes are grouped together with one switch. this group of genes, along with the sections of dna that regulate them, is called a

Suppose a particular species of tulip plant has three alleles for the gene that codes for flower color. the cr allele produces red tulips, the cp allele produces purple tulips, and the cw allele produces white tulips. cr is dominant over cp and cw, and cp is dominant over cw. for each of the following crosses, determine the expected ratio of offspring for each flower color. cr cp x cp cw cr cw x cp cw 1 red: 1 purple : 0 white, 1 red: 2 purple: 1 white, 2 red: 1 purple 1 white, 1 red: 3 purple : 0 white, 2 red: 0 purple : 2 white, 2 red: 2 purple : 0 white