This discussion question is designed to be answered with the materials presented in Chapters 4, 5, and 6 (Weeks 4-6) where you will be learning more about the structure of the cell, the function of different organelles, and metabolism. You will be focusing on the nucleus and the mitochondria in order to develop your understanding of the structure and function of these two types of organelles. Then you will learn about how scientists have used their biological understanding of the difference between how the nucleus and mitochondria are passed to offspring to further our understanding of human evolution.
Most of us are familiar with the idea that our genes (DNA) are located in the nuclei of our cells. We also know that when we reproduce (sexually reproduce) two parents contribute genetic information to make the nucleus of the first cell of the offspring. In other words, the sperm contributed by the father combines with the egg contributed by the mother to produce a cell called a zygote which will undergo cell division to make the new offspring.
However, did you know that mitochondria also have genes (DNA)? These genes are important for producing proteins that help us with energy metabolism. Defects in these genes have been correlated with several diseases. (See http://ghr.nlm.nih.gov/mitochondrial-dna for more information.)
If the nucleus in the first cell of the offspring (the zygote) comes from a combination of the genetic material of the egg and the sperm, where do the mitochondria in the first cell (zygote) come from? You’ll be answering this as you investigate mitochondrial and mitochondrial inheritance.