What are genes? Explain how they influence our physical and psychological traits.

- Genes are the basic units of heredity; they are responsible for guiding the process of creating the proteins that make up our physical structures and regulate development and physiological processes throughout the lifespan.
- Genes are comprised of DNA (deoxyribonucleic acid) molecules formed in a double helix shape that contain four amino acids: adenine (A), cytosine (C), guanine (G), and thymine (T).
- The sequence of amino acids represents a code which can be used to create proteins.
- Traits that show genetic variation, such as eye color, the shape and size of facial features, and even personality, do so because of differences in amino acid sequencing of A, C, G, and T, and interactions with the environment.

Genes are "units" of hereditary information.  Genetic recombination allows differences and diversity in the genes of non-identical individuals.  The genes that are expressed in an individual play a role in the physical and psychological traits of that individual.  Genes encode gene products, which are used and needed for various processes.

Genes are the units of hereditary information. It carries the information from one generation to the next generation. If there is a gene that cause disease then the presence of that gene will affect the particular physical trait.