Cells and Molecules - Brutes or Angels: Human Possibility in the Age of Biotechnology - page 6

fig. 1.3. Cell structure seen by
light microscopy (lm, top ) and
transmission electron microscopy
(Tem, bottom ). Photographs are of
a gland in crickets that produces a
hormone controlling insect growth
and development. The dozens of
small roundish gray objects (n) with
dark speckles in the top photo are
cell nuclei. each cell has a nucleus
that contains all of the cricket's
genetic information. Portions of
three cells and their nuclei are shown
in the bottom photo. A specialized
part of the nucleus, the nucleolus
(nu) is visible in one cell and num-
erous mitochondria (m) appear in
the cell's cytoplasm surrounding
each nucleus. Tem reveals more
subcellular detail than lm, but lm
can show how cells are organized
into tissues and organs.