Use what you've learned this week to answer the essential question: " How do genes determine traits? " Your answer can be posted to Google Classroom, and should use evidence from this week's learning activities to support your claim.

Proteins, Genes, and Chromosomes

Proteins and Traits A protein is a substance that makes up much of an organism's structure and helps it to function. The types and amounts of proteins an organism makes help determine its traits.

Structure of Proteins and Resulting Traits Changes in a protein's structure can change its functionality and an organism's traits.

Proteins and Eye Color Variation in the amount of a protein in cells results in different traits, such as a different amount of melanin resulting in a different eye color.

Gene Expression The structure of a protein is determined by a gene, which is a segment of DNA that contains the instructions for making the protein. Some genes regulate other genes. An organism does not directly inherit traits from its parents. Rather, it inherits the genes that help determine its traits from its parents.

The Location of Genes Every gene that an organism has is found in a specific location on a specific chromosome. Humans all have essentially the same genes in the same locations in nearly every cell of their body.

Alleles Each gene has variations, or alternate forms, which are called alleles. Although a gene may have many alleles in an entire population of people, an individual can have only two alleles for each gene, one on each chromosome of a pair.

Chromosome Pairs Humans have 23 pairs of chromosomes. With the exception of the 23rd chromosome in males, these pairs have the same genes. The 23rd pair of chromosomes determine someone's sex. Human females have two X chromosomes. Males have one X and one Y chromosome.