2. At the end of this lesson,the
learners should be able to:
●describe the structure of the cell
membrane or plasma membrane & its role in
cell;
●describe the movement of substances
into & out of the cell;
●explain transport mechanisms in
cells such as passive,active & bulk trasports;and
●differentiate endocytosis from exocytosis.
3. CELL
MEMBRANE
●Serves as a
boundary
between the cells
internal& external
environments .
●Exhabits selective
permeable,which
is why it is referred
to as a semi-permeable
membrane
4. STRUCTURE &
ORGANIZATION
●The main body of the
plasma membrane is
composed of amphipothic
molecule known as a phospholipid
●Ampiphatic both hydrophobic &
hydrophilic
5. STRUCTURE &
ORGANIZATION
●this unique structure
allows the plasma
membrane to adopt a
bilayer structure wherein
the hydrophilic surface is
facing both the aqueous
external environment and
cytosol
7. STRUCTURE & ORGANIZATION
●Because of its
hydrophobic
properties the tails
form an internal
layer.These factors
cause the plasma
membrane to be semi-
permeable to certain
substances
9. The components of the plasma
membrane can be divided into
three,
TRANS
MEMBRANE
PROTIENS
●these are the protiens that
regulates the movement of
molecules
●these protiens form the
transport mechanisms of the
cell
●they are composed of
carriers,channels & receptors
protiens
10. ●Determines and maintains
the structure of plasma
membrane
●They are also responsible
for the shape of the cell &
the attachment of
micromolecules in cell
membrane
INTERIOR PROTIEN NETWORK
14. The Types of Transport
Mechanisms
PASSIVE TRANSPORT
●It is a kind of movement of
materials that does not
require any metabolic energy
from the cell but rely solely
on the physical properties of
the substances themselves.
●Region of higher concentration to a
region of lower concentration
15. It involves 3 types
SIMPLE DIFFUSION
●The movement of ions
& molecules from
high concentration to
low concentration
is known as diffusion
16. FACILITATED DIFFUSION
●It is the movement of
materials across the
plasma membrane by
means of transport
protiens
●Proteins manange &
assist the movement of
solutes across the
membrane
17. ●Proteins provide a
small hydrophilic
passageway for
V.S
specific molecules & ions
●Some channels can
remain open most of the
time leak channels
which can be opened or closed
gated channels (Stimulus)
Requires the molecules
being transported to
attach itself to the
carrier protein
.The protein will
change it shape to
shuttle the molecules
across the membrane
CHANNEL PROTEIN CARRIER PROTEIN
18. OSMOSIS
●Water moves in the
direction of the solutes until
the # of free water
molecules are equal known
as osmotic balance
●The movement isinfluenced by the
presence of solutes & their ability to
pass through the membrane
20. ACTIVE TRANSPORT
●This type of transport
relies on the expense of
cell energy,(ADENOSINE
TRIPHOSPHATE)ATP
●This expenditure is needed to
move molecules against
concentration gradient to
maintain internal conditions
22. PRIMARY ACTIVE TRANSPORT
●ion pumps
●it is an internal & uphill
mode of transport where
a transport protein
directly uses energy from
ATP
phosphorylation.
23. SECONDARY ACTIVE
TRANSPORT
●A molecule is transported
due to the difference in
energy from the
phosphorylation of energy
●Transport of potassium ions from outside
the cell to inside as the protein reverts its
shape due to the loss of the phosphate loss.
25. COUNTER TRANSPORT
●it occurs when one
transporter moves
two different
molecules across the
membrane in
different directions
UNIPORT & ANTIPORT
26. BULK/VESICULAR TRANSPORT
●it also requires an
expenditure of energy
●macromolecules or larger
molecules are entering the
cell plasma membrane
●molecules are massive
,enough energy is required
for the molecules possibly
enter the cell.
27. ●Process by which
cells take in substances
from outside of the
cell by engulfing them
in a vesicle.
●material is taken in or bring
the particles into a cell using
an extension or portion of
the plasma membrane
●process by cells
release particles from
within the cell into the
extracellularspace
●the waste material are
transported out of the
cell by the infolding
parts of the membrane
ENDOCYTOSIS
EXOCYTOSIS
28. ●takes in fluid & solutes
PINOCYTOSIS
●fluid is brought into the cell and
also require transport proteins when
macromolecules are taken inside the
cell
Types of ENDOCYTOSIS
Cell drinking
29. Types of ENDOCYTOSIS
PHAGOCYTOSIS
●takes in larger
substances bacteria
●happens in unicellular organisms like
amoeba that ingest food & larger materials
are enclosed in a vesicle inside the cell
,fuses with lysosome & digested the
materials to be used by the cell
Cell eater
30. Types of ENDOCYTOSIS
RECEPTOR MEDIATED
●Receptor proteins on the cell surface
are used to capture a specific target
molecule.
38. 4.It is a kind of movement of materials
that does not require any metabolic
energy from the cell but rely solely on
the physical properties of the
substances themselves.
