Cells and Molecules - Brutes or Angels: Human Possibility in the Age of Biotechnology - page 10

fig. 1.5. mitochondrion structure and function. mitochondria are
double-membrane organelles. They oxidize food molecules in their
inner chamber and use the released energy to produce ATP molecules
that are transported out of the mitochondrion for use by the cell. not
shown is the bacterial-like, mitochondrial chromosome, a circular,
double-stranded DnA molecule within the inner chamber. mitochondrial
chromosomes are similar in structure to the prokaryotic cell
chromosome depicted in igure 1.4.
lysosomes are small membrane-bound vesicles that serve as the cell's
digestive system. inside lysosomes are powerful enzymes that break down
large, ingested food molecules into smaller molecules that are eventually
oxidized inside mitochondria or used to construct other components of
the cell. 6 lysosomes also digest worn-out organelles, recycling the break-
down products for new building projects inside the cell. sometimes lyso-
somes go berserk, digesting the entire cell from the inside out. This hap-
pens in the lungs of persons afflicted with asbestosis, a disease caused by
asbestos fibers entering lung cells. inherited diseases called lysosomal stor-
age disorders result from genetic defects in lysosomes, rendering them un-
able to digest certain materials. The results are an abnormal accumulation
of undigested material inside the cell and devastating diseases, including
Tay-sachs disease, that cause mental retardation and joint and skeletal de-
formities. fortunately, all known lysosomal storage disorders can now be
diagnosed prenatally by amniocentesis, so their occurrence is declining.