Theories of Aging
Aging theories explains the cumulative damage, be it from oxidative stress, telomere shortening, or mitochondrial dysfunction that contributes to the gradual decline in cellular function and overall aging. Theories of aging are:
Oxidative Stress Theory
The oxidative stress theory of aging suggests that age-related reductions in physiological functions are caused by a slow accumulation of oxidative damage caused by reactive oxygen species (ROS) to macromolecules. This damage increases with age and is associated with life expectancy. ROS are byproducts of cellular metabolism, and if not properly balanced by antioxidants, they can damage cellular components like DNA, proteins, and lipids.
Telomere Theory
The theory suggests that telomeres shorten each time a cell divides, eventually disappearing. Once telomeres are gone, the cell can no longer copy its DNA and ages, becoming unable to replicate. Regular physical activity is believed to positively affect telomere length, prolonging human lifespan.
Mitochondrial Theory
The mitochondrial theory of aging is a theory that suggests that damage to mitochondria and mitochondrial DNA (mtDNA) leads to aging in humans and animals. It is a variant of the free radical theory of aging. Mitochondria are the main producers of ROS in the cell. According to the theory, mitochondria accumulate ROS-induced damage and become dysfunctional with age. Over time, cell function declines, causing aging and death.
What is Senescence? – Senescent Cells And Senescence In Plants
Senescence is the process by which cells stop dividing and enter a state of permanent growth arrest without undergoing cell death. Senescence cells get old and weaken, causing a decline in tissue function and decay. Senescence in plants is a programmed death of leaves as part of developmental cycles. In animals, senescent cells contribute to aging and age-related diseases.
Senescence can be induced by unrepaired DNA damage or other cellular stresses. It plays a role in normal development, maintains tissue homeostasis, and limits tumor progression. In this article, we will read about what is senescence, its causes, and effects, senescent cells, the different types of senescence in plants, theories of aging, factors affecting senescence, and its importance.
Table of Content
- Senescence Definition
- Senescence Meaning
- Senescent Cells
- Causes of Senescence
- Types of Senescence
- Theories of Aging
- Effects of Senescence
- Factors that Influence the Senescence in Plants
- Importance of Senescence