Which of the following correctly describes the relationship between chromosomes and
genes? (A) There are many genes located on a single chromosome or (B) there are many
chromosomes within one gene.
DNA is made up of a sequence of bases on a sugar–phosphate backbone. Certain stretches on a strand of DNA are called genes. The base sequence of these genes provides a code for the construction of particular
proteins that play a role in the organism the DNA belongs to. The proteins may be for building structures, for catalyzing reactions, for digestion
or excretion, or any number of other purposes.
Genes can only be copied for the purposes of making protein when the DNA strands are
loose and can be separated. But when DNA is not in use, it coils and condenses into a chromosome. Since a chromosome contains an entire strand of DNA, it will contain all of the genes
located on different stretches of that strand. So the relationship between genes and chromosomes is that there are multiple genes
located on a chromosome.
Therefore, the correct answer is (A). The relationship between genes and chromosomes is that there are many genes located
on a single chromosome.