Cytoplasmic
membrane
The prokaryotic cell
has a cell membrane called the cytoplasmic membrane that froms
the outer structure
of the cell and separates the cell’s internal structure from the
environment. The
cytoplasmic membrane is a membrane that provides a selective barrier
between the
environment and the cell’s internal structures.
The
function of the Cytoplasmic Memebrane
The cytoplasmic
membrane regulates the flow of molecules (such as nutrients) into the
cell and removes
waste from the cell by opening and closing passages called channels. In
Photosynthesis
prokaryotes, the cytoplasmic membrane functions in energy production
by collecting energy
in the form of light.
The cytoplasmic
membrane is selectively permeable because it permits the transport
some substances and
inhibits the transport of other substances. Two types of transport
mechanisms are used
to move substances through the cytoplasmic membrane. These are
passive transport and
active transport.
Cytosol
and Cytoplasm
The cytosol is the
intracellular fluid of a prokaryotic cell that contains proteins, liquids,
enzymes, ions, waste
and small molecules dissolved in water, commonly referred to as
semifluid. Substances
dissolved in cytosol are involved in cell metabolism. The cytosol
also contains a
region called the nucleoid, which is where the DNA of the cell is located.
Unlike human cells, a
prokaryotic microorganism has a single chromosome that isn’t
contained within a
nuclear membrane or envelop. Cytosol is located in the cytoplasm of
the cell. Cytoplasm
also contains the cytoskeleton, ribosomes and inclusions.
Ribosome
A ribosome is an
organelle within the cell that synthesizes polypeptide. There are
thousands of
ribosomes in the cell. A ribosome is comprised of submits consisting of
protein and ribosomal
RNA, which is referred to as rRNA. Ribosomes and their submits
are identified by
their sedimentation rate. Sedimentation rate is the rate at which
ribosomes are drawn
to the bottom of a test tube when spun in a centrifuge.
Sedimentation rate is
expressed in Sydberg (s) units. The sedimentation rate reflects
mass, size and shape
of a ribosome and its submits.
Inclusions
An inclusion is a
storage area that serves as a reserve for lipids, nitrogen, phosphate,
starch and sulphur
within the cytoplasm. Scientists use inclusion to identify types of
bacteria. Inclusions
are usually classified as granules.
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