| Anti-oxidants - |
Compounds
that neutralize oxygen radicals. Some are enzymes like
SOD while others are nutrients such as vitamin C, vitamin
E, and beta-carotene. High levels of anti-oxidants have
been associated with longer life spans. |
| Anti-proliferative
genes - |
Genes
that inhibit cell division or proliferation; also known
as tumor suppressor genes. |
| Average
life span - |
The
average number of years that members of a population live. |
| Biomarkers - |
Biological
changes that characterize the aging process; because biomarkers
are considered a better measure of aging than chronological
time, studies are underway to identify biomarkers in cells,
tissues, and organs. |
| Caloric
restriction - |
An
experimental approach to studying longevity 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. |
| Chromosomes - |
Structures
in the cell's nucleus, made up of protein and DNA, that
contain the genes. |
| DNA
(deoxyribonucleic acid) - |
A
large molecule that carries the genetic information necessary
for all cellular functions, including the building of
proteins. Damage to DNA and the rate at which this damage
is repaired may help determine the rate of aging. |
| 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. |
| Gene - |
A
segment of DNA that contains the "code" for a specific
protein or other product. |
| Gene
expression - |
The
process by which genes are transcribed and translated
into proteins. Age-related changes in gene expression
may account for some of the phenomena of aging. |
| Glycation - |
The
process by which glucose links with proteins and causes
them to bind together, thus stiffening tissues and leading
to the complications of diabetes and perhaps some of the
physiologic problems associated with aging. |
| Hayflick
limit - |
The
finite number of divisions of which at cell is capable. |
| Interleukins - |
Substances
secreted by lymphocytes; their levels vary with age. |
| Lymphocytes - |
Small
white blood cells that are important to the immune system.
A decline in lymphocyte function with advancing age is
being studied for insights into aging and disease. |
| Maximum
life span - |
The
greatest age reached by any member of a given species. |
| Mitochondria - |
Cell
organelles that metabolize sugars into energy. Mitochondria
also contain DNA, which is damaged by the high level of
free radicals produced in the mitochondria. |
| Proliferative
genes - |
Genes
that promote cell division or proliferation; also known
as oncogenes. |
| Photoaging - |
The
process initiated by sunlight through which the skin becomes
drier and loses elasticity. Photoaging is being studied
for clues to aging because it has the same effect as normal
aging on certain skin cells. |
| Proteins - |
Molecules
made up of amino acids arranged in a specific order determined
by the genetic code. Proteins are essential for all life
processes. Certain ones, such as the enzymes that protect
against free radicals and the lymphokines produced in
the immune system, are being studied extensively by gerontologists. |
| Telomeres - |
Repeated
DNA sequences found at the ends of chromosomes; telomeres
shorten each time a cell divides. |
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