Final answer:
In antibodies, light chains consist of fewer nucleotides compared to heavy chains because heavy chains contain more domains (three or four constant domains in addition to one variable domain), leading to a longer sequence of amino acids and correspondingly more nucleotides.
Step-by-step explanation:
The student asked if there are fewer nucleotides in the light chain or heavy chain of antibodies. To answer this, it is helpful to understand the structure of these chains. Light chains contain one variable domain (VL) and one constant domain (CL), while heavy chains contain one variable domain (VH) and either three or four constant domains (CH) depending on the antibody class. Because heavy chains have additional constant domains, they are generally longer and thus, have more amino acids and nucleotides than light chains.
Considering the genetic rearrangement during B cell differentiation, the light chain's gene has 40 V (variable) segments and 5 J (joining) segments, while the heavy chain's gene also includes diverse (D) segments in this process, which are not present in light chains, contributing to the additional length. Therefore, in terms of nucleotide count, there are more nucleotides in heavy chains due to the additional domains and complexity of the genetic rearrangement.