|
Anti-oxidants
|
Compounds
that neutralize oxygen radicals. Some are enzymes like SOD while
others are nutrients such as vitamin C, E, and beta-carotene.
|
- Average
life span
|
The
average number of years that members of a population live.
|
- Caloric
restriction
|
An experimental
approach in which life spans of laboratory animals have been
extended by reducing calories while the necessary level of nutrients
is maintained.
|
- Cell
senescence
|
The
stage at which a cell has stopped dividing permanently.
|
| Differentiation |
Pluripotent
stem cells undergo further specialization into stem cells that
are committed to give rise to cells that have a particular function. |
- Free
radicals
|
Molecules
with unpaired electrons that react readily with other molecules.
Oxygen-free radicals, produced during metabolism, damage cells
and may be responsible for aging in tissues and organs.
|
| Heat
Shock Proteins |
Produced
when cells are exposed to stresses, heavy metals, and chemicals.
Levels at which they are produced depend on age. |
- Interleukins
|
Substances
secreted by lymphocytes: their levels vary with age.
|
- Maximum
life span
|
The
greatest age reached by any member of a given species.
|
- Photoaging
|
The
process initiated by sunlight through which the skin becomes
drier and loses elasticity.
|
| SOD |
Superoxide
dismutase; converts oxygen radicals into hydrogen peroxide,
which then degrades to oxygen and water. |
- Telomeres
|
Repeated
DNA sequences found at the ends of chromosomes; telomeres shorten
each time a cell divides.
|
- Telomerase
|
Enzyme
in specialized reproductive cells and most cancer cells, which
adds back telomeric DNA to the ends of chromosomes. Causes human
cells to continue to divide long past the time when they normally
stop dividing. |
