Final answer:
Every person has a copy of the APP gene, which is located on chromosome 21. Humans typically have two copies of this chromosome, contributing to the genetic diversity and functionality within our bodies. Gene expression varies among different cells, resulting in diverse cell types despite identical genetic makeup.
Step-by-step explanation:
Yes, everyone has a copy of the APP gene as it is located on chromosome 21, and all humans have this chromosome. Genes, such as the one for APP protein, are present in every cell of the body, since each cell typically contains a full set of chromosomes, which are structures that house our genetic material, or DNA. Normally, humans have two copies of chromosome 21, one inherited from each parent. It's this complete set of chromosomes in every cell that contributes to the genetic diversity and functionality within our bodies.
Furthermore, differences in gene expression can lead to cells creating different proteins, which is why not all cells are the same despite having the same genetic makeup. This gene expression is a process controlled by regulatory mechanisms within the cell, determining when and how much of a particular protein is made.