What is the basic unit of heredity that can influence both appearance and function?

• A. Gene
• B. Chromosome
• C. Protein
• D. Nucleotide

Answer: (A)

The basic unit of heredity that can influence both appearance and function is a gene. Genes are segments of DNA that carry the instructions for the synthesis of proteins, which play critical roles in the structure and function of all living organisms. Each gene can determine specific traits, such as eye color or height, by coding for the proteins that are responsible for those characteristics. In addition to influencing physical traits, genes also regulate metabolic processes and other biological functions, making them fundamental to both phenotypic expressions and the functional aspects of an organism.

The other options, while important in the context of genetics, do not serve as the basic unit of heredity in the same way. Chromosomes are structures that organize and carry genes but are made up of DNA and proteins. Proteins are the products of gene expression and do not themselves constitute a unit of heredity. Nucleotides, the building blocks of DNA, are essential for forming genes but do not carry hereditary information independently. Thus, in the context of heredity, genes are the specific units that contain and convey genetic information.