Change seen in mitochondria due to aging is?
**Core Concept**
Mitochondrial dysfunction is a hallmark of aging, and various changes occur within these organelles as part of the aging process. Mitochondria are the primary site of energy production in cells through oxidative phosphorylation.
**Why the Correct Answer is Right**
One significant change seen in mitochondria due to aging is the accumulation of **mitochondrial DNA (mtDNA) mutations**. These mutations disrupt the mitochondrial respiratory chain, leading to a decline in ATP production and an increase in reactive oxygen species (ROS) generation. The accumulation of mtDNA mutations is thought to contribute to the aging process by promoting cellular senescence and tissue damage. The **mitochondrial permeability transition pore (mPTP)** also becomes more active with age, leading to mitochondrial swelling and eventual cell death.
**Why Each Wrong Option is Incorrect**
* **Option A:** Mitochondrial biogenesis is actually decreased with age, not increased, as cellular resources are redirected towards maintaining existing mitochondria.
* **Option B:** Mitochondrial membrane potential is actually decreased with age, not increased, due to the accumulation of mtDNA mutations and ROS.
* **Option C:** The mitochondrial unfolded protein response (UPRmt) is activated in response to mitochondrial stress, but it is not the primary change seen in mitochondria due to aging.
**Clinical Pearl / High-Yield Fact**
The accumulation of mtDNA mutations with age contributes to the development of age-related diseases, including neurodegenerative disorders such as Alzheimer's and Parkinson's disease, as well as metabolic disorders such as diabetes.
**Correct Answer:** C.