This short article was designed for anatomy and physiology students studying the cell. The class focuses on how disease states can often be traced back to problems with cells. Senescence, or aging, has been linked to a build-up of mutations in mtDNA. Each mitochondrion divides independently, each contains its own DNA. This observation supports the endosymbiosis theory which suggests that organelles like mitochondria and chloroplasts were once independent prokaryotes that came to live inside eukaryote cells. Because of this unique property of mitochondria, mtDNA can accumulate mutations over time separate from the cell’s DNA.
Students are asked to read a short passage describing mitochondria and the “Mitochondrial Theory of Aging.” They must then identify the claim being made by the author, the evidence provided and then state the reasoning for the claim (or the connection between the claim and the evidence.)
Sometimes I grade CER’s and sometimes I do them as part of an overall class discussion. If grading, I use a 1-2-3 format. 1 pt for identifying the claim, 2 pts for the evidence, and 3 pts for reasoning.
Grade Level: 11-12
Time Required: 15-20 minutes