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The process by
which a cell dies at a natural, "pre-programmed" time.
The structural and functional unit of an organism that join together
to form tissues. Examples: muscle cells, skin cells, and nerve cells.
Thread-like structure in the nucleus that carries genetic information.
A normal human body has 23 pairs of chromosomes (46 total chromosomes).
Twenty two pairs are called somatic, or "body" chromosomes.
The remaining 2 chromosomes are called "sex" chromosomes and
determine wether you are a male or a female.
A protein that initiates biochemical reactions in the body. It is
neither created, nor destroyed during the reaction. Examples: telomerase
(helps prevent chromosomes from shortening), lactase (helps dissolve
milk sugar), and lipase (helps break down fat).
cell: A cell that becomes sex cells (sperm and egg).
A cell type that can invade and move to distal parts of the body
and end the life of a patient. Example: Cancer.
Division of a somatic (body) cell to form two daughter cells.
A group of tissues that come together to perform a common function.
Examples: the heart is a collection of cardiac tissue and the brain
is a collection of nervous tissue.
The smallest unit of a cell that perform specific functions. Examples:
the nucleus contains genetic information, the ribosome packages materials,
and the mitochondria make energy.
system: A collection of organs that work together to perform
a specific function. Example: Digestion is performed by the mouth, esophagus,
stomach, small intestine, and large intestine.
Ribonucleic acid. It is a strand of base pairs that helps code for
new DNA strands when a cell divides.
The process of cellular aging.
cell: A cell other than a germ cell.
A collection of cells that come together to perform a specific function.
Examples: Muscles are formed by muscle cells, nerves are formed by nervous
cells, and glands are formed by secretory cells.