animal cell
Overview
Like all eukaryotic cells, the cells
of animals contain a variety of membrane-bounded
organelles. These include:
Animal cells are distinct from other eukaryotes, most notably plant
cells, however, in that they lack cell
walls and chloroplasts, and they
have smaller vacuoles. Detailed
description
Animal cells are all built to the same basic pattern. The nucleus is a membrane-bounded
sac containing the genetic material of the cell. The genetic information
is coded for in DNA (deoxyribonucleic acid).
The nuclear membrane is perforated
by pores that are important in controlling the exchange of substances between
the nucleus and cytoplasm.
The cytoplasm contains numerous organelles. Prominent are the mitochondria,
sausage-shaped bodies that are responsible for energy production. Scattered
in the cytoplasm are several multi-layered membrane systems: the smooth
endoplasmic reticulum, the rough endoplasmic reticulum, and the Golgi apparatus
(or Golgi body). The smooth endoplasmic reticulum is concerned with the
manufacture of lipids molecules while the
rough endoplasmic reticulum manufactures proteins
destined for export from the cell. The granular nature of the rough endoplasmic
reticulum is created by the presence of globular ribosomes on the surface
of its membranes and it is on the ribosomes that proteins are assembled.
The Golgi apparatus, among other things, modifies some of these proteins.
Sacs of enzymes, called lysosomes, are concerned
with breaking down some of the large molecules that enter the cell.
Related category
• CELL
BIOLOGY
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