Final answer:
A gene is the basic unit of heredity, consisting of a DNA sequence that codes for proteins or RNA molecules. Genes are located on chromosomes and passed on through gametes. Differences in these sequences, known as alleles, dictate the diversity of traits in organisms.
Step-by-step explanation:
Broadly defined, a gene is a unit of heredity. It is a specific sequence of DNA that codes for a particular protein or RNA molecule, determining the traits that are passed from parents to offspring. These sequences are housed on chromosomes, which are long strands found within the cell nucleus. Each chromosome consists of many genes, and the entire set of chromosomes in an organism makes up its genome. During sexual reproduction, genes are transmitted to the next generation via gametes, which are haploid reproductive cells like sperm or eggs.
The inherited genes can appear in different forms known as alleles, leading to the expression of various traits in the offspring. The field of genetics, which studies heredity and the variation of inherited characteristics, began to deeply understand these principles after the rediscovery of the works of Gregor Mendel, whose experiments with pea plants laid the groundwork for our knowledge of genetic inheritance.