Book Definition: "Segment of a chromosome that encodes the directions for the inherited physical and mental characteristics of an organism. Genes are the functional units of a chromosome." (Zimbardo 66)


Each cell in your body contains 25,000-35,000 genes which determine the physical traits of an individual. Physical traits are hereditary, or inherited from preceding relatives (ex: parents, grandparents, and great-grandparents). Different genes are dominant or recessive, and thus change the likelihood of having a particular trait. Genes make up chromosomes.

In Your Own Words

  • The instructions that make the inherited biological characteristics of an organism.
  • The thing that holds the recipe to create your body.
  • Genes hold genetic information and get passed down through generations in a family by reproduction.
  • Genes are the nature part of making you who you are.
  • Decide what physical and Mental charasteristics you have


  • Your mother has blue eyes but your father has brown eyes. Both of your siblings have brown eyes, but you have blue eyes. This shows your siblings received the dominant gene of brown eyes and you received the recessive gene.
  • Your mother has long eye lashes and your father has short eye lashes. You have long eyelashes and therefore your genotype must be Ll. Your father has a ll genotype since short eyelashes are recessive he must have two recessive genes for the trait to be apparent. Your mother's genotype could be LL or Ll because only one dominant gene is needed for the dominant trait to show. Your genotype must be Ll because you have the dominant trait of long eye lashes and therefore got the L gene from your mother. Since you receive one gene from each parent you must also have the l gene or the recessive gene as your father is ll.

Additional Resources

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