The structure of plasma membrane of Bacteria, its layers, transport mechanism.

1. Submitted To:- Submitted By:-
Ms. DEVKI SONAL SINGH
(18BMIN001)

2.  Outermost / Cell membrane.
 Thickness is about 5-8 nm.
 Selectively permeable.
 Serves as outer boundary.
 Made up of Phospholipids, Proteins, and
conjugated molecules.
 Separate and protect cell from external
environment.

3.  Proposed in 1972, by Singer and Nicolson.
 “Cell membrane is lipid bilayer in which
proteins are partially embedded like floating
icebergs in sea.”
 It describes the plasma membrane as a
flexible boundary of a cell. The phospholipids
move within the membrane.

5.  The plasma membrane is composed of two
layers of phospholipids back-to-back.
 It consists of some components:-
i. Phospholipids
ii. Peripheral (extrinsic) protein
iii. Integral (Intrinsic) protein
iv. Cholesterol
v. Glycoprotein
vi. Glycolipid

7.  Phospholipids are lipids with a phosphate
attached to them. They have fatty acid tails
(hydrophobic) and phosphate group head
(hydrophilic) arranged as a bilayer.
 Phospholipids, glycolipids, cholesterol are
amphipathic lipids containing hydrophobic
and hydrophilic ends.

8.  Also called as
Peripheral Protein.
 Proteins loosely
associated with
membrane surface.
 Located entirely
outside of the lipid
bilayer.
 Either on the
extracellular or
cytoplasmic surface.
 Also called as
Integral Protein.
 Tightly bound to
lipid layer.
 Provides channel for
the water-soluble
substances

9.  Transport proteins allow needed substances
or waste materials to move through the
plasma membrane.

10. ACTIVE TRANSPORT PASSIVE TRANSPORT
 Diffusion against
concentration
gradient.
 Low  High
 Uses a protein
pump.
 Requires ATP.
 SIMPLE diffusion
i. Diffusion of non-
polar, hydrophobic
molecules (lipids)
ii. High  Low
 FACILIATED
diffusion
i. Diffusion of polar,
hydrophilic
molecules.
ii. Through a protein
channel.
iii. High  Low