1. By
Maryam Shakeel

2.  The cell wall is the tough, usually flexible
but sometimes fairly rigid layer that
surrounds becteria. It is located outside
the cell membrane
 Mostly in bacteria cell wall chemically
composed of peptidoglycan (murein). The
cell wall strengthens the plasma
membrane and prevents the cell from
bursting.

3. Gram +ve Gram-ve
with the with the
Gram stain. Gram
G+ cells are stain. G-
Purple cells are red.

4. Gram
Gram - E. coli cells
+ Staphylococcus cells.

5.  Gram-positive cell walls consist of many
layers of peptidoglycan and also contain
teichoic acids. Teichoic acids may:
 bind and regulate movement of cations into
and out of the cell
 prevent extensive wall breakdown and
possible cell lysis during cell growth
 provide much of the cell wall's antigenicity

7.  Gram-negative bacteria have a
lipopolysaccharide-lipoprotein-phospholipid
outer membrane surrounding a thin
(sometimes a single) peptidoglycan layer.
Gram-negative cell walls have no teichoic
acids.

9. G +ve G -ve

11. • From • Maintain the
Osmolysis shape of cell
Structural
Protection
Support
Critical Filtering
Structure mechanism
• Becteria can • Does not allow
not live without motion of
it large molecules

13.  Surrounds the cell's cytoplasm and
regulates the flow of substances in and out
of the cell.
 The plasma membrane is composed of a
phospholipid bilayer (two layers) embedded
with proteins and other molecules. The
phospholipids are not fixed relative to each
other and able to flow past each
other, making the membrane fluid.

14.  Bacteria can have a wide variety of fatty
acids within their membranes. Along with
typical saturated and unsaturated fatty
acids, bacteria can contain fatty acids with
additional methyl , hydroxy or even cyclic
groups. The relative proportions of these
fatty acids can be modulated by the
bacterium to maintain the optimum fluidity of
the membrane (e.g. following temperature
change).

15.  Phospholipids are molecules composed of
two long, hydrocarbon "tails" and a
phosphate group "head." The hydrophilic
(water-attracted) phosphate group "heads"
form the internal and external surface of the
plasma membrane. The hydrophobic (water-
repelled) tails form the interior of the plasma
membrane.

16.  Embedded in the plasma membrane are
proteins that perform multiple functions,
including the detection of chemicals in the
cell's environment and the transportation of
materials into and out of the cell.

17.  the region between the cytoplasmic and outer
membranes. The periplasm contains the
peptidoglycan layer and many proteins
responsible for substrate binding on
hydrolysis and reception of extracellular
signals.

18.  passive transport of many ions, sugar and
amino acids across the outer membrane.
These molecules are therefore present in
the periplasm.
 acting as a permeability barrier for most
molecules and serving as the location for the
transport of molecules into the cell.

19.  prokaryotic membranes also function in
energy conservation as the location about
which a proton motive force is generated.
 bacterial membranes (with some exceptions
e.g. Mycoplasma and methanotrophs)
generally do not contain sterols.
 bacteria can have a wide variety of fatty
acids within their membranes.

20.  It prevents only  prevents toxicity to
large molecules the cell whereas cell
from entering the membrane prevents
cell. entry of smaller
 Cell wall is molecules.
completely  cell membrane is
permeable semi-permeable.

21.  The function of the  The cell membrane
cell wall is to provides support to
provide strength the cytoskeleton of
and rigidity to the the cell, gives shape
cell. to the cell
 It protects the cell  it maintains the
against mechanical potential of the cell,
forces. helps in
 It is made up of communication with
peptidoglycan. other cells, and act
as molecular signals
 It is made up of lipid
and protein.