Question

"Proteins control the expression of various characters." Explain this statement by taking an example of "tallness" as a characteristic in plants.

Hint:

Proteins, encoded by genes, are the key regulators of various traits such as height, by influencing growth processes at the cellular level.

Answer 1

In genetics, the expression of characteristics such as "tallness" in plants is controlled by specific genes, which are sections of DNA found in chromosomes. These genes code for proteins that directly influence the development and functioning of cells. These proteins regulate various biological processes, including growth. Tallness in plants can be explained using the example of Mendelian inheritance. In pea plants, for example, tallness is governed by a dominant allele "T," while the allele for shortness is recessive, "t."
- The dominant allele "T" codes for a protein that promotes cell division and elongation, thus resulting in tall plants.
- The recessive allele "t" does not produce the same protein, resulting in shorter plants when inherited in a homozygous form (tt).
- When a plant inherits one "T" allele (from either parent), it produces enough of the protein to exhibit the tall phenotype. Thus, proteins (encoded by genes) control the expression of tallness by regulating growth-related proteins in plants.