for more saad-_-14@hotmail.com

1. Present by Saad Sami Almuhanna

2. • What are the different Mechanisms
responsible of transport?
• How the large molecules transport
out from and into the cell ?
• What are the Modifications, their
functions, examples ?

3. • Passive transport
• Active transport

4. 1.Diffusion
2. Facilitated diffusion
3. Osmosis

5. Movement from high concentration to low concentration.

6. • Channel proteins
Provide corridors that allow a specific molecule or ion to
cross the membrane.
• Carrier proteins
Undergo a subtle change in shape that translocate the
salute-binding site across the membrane.

7. • The movement of water across a semi permeable
membrane.
• Osmosis is the movement of water (red dots) through a
semipermeable membrane to a higher concentration of
solutes (blue dots).

8.  Process that moves materials across the
plasma membrane
 Requires energy from the cell in the form of ATP
 Materials move against the concentration
gradient:
low concentration high concentration
 3 Kinds:
Pumps, Endocytosis, and Exocytosis

9. 1. An ATP molecule breaks down into ADP,
releasing a phosphate group and a whole lot of
energy.
2. The phosphate group attaches to a protein
pump, causing it to change its shape so that it
can move a small molecule or ion across the
plasma membrane.
3. The protein changes shape again so that the
molecule can be released on the other side.
 There are many types of carrier proteins and they
only carry specific molecules across the plasma
membrane.

10. Larger molecules cannot fit. Because they are too big so they
enter the cell by endocytosis and go out by exocytosis

11.  Larger materials transport into the cell it is
includes three slightly different processes:
 Endocytosis:-
1. Phagocytosis: cell eating
2. Pinocytosis: cell drinking
3. Receptor mediated endocytosis

12. 1. Phagocytosis:-
endocytosis of solid particles.
- cell engulfs particle with pseudopodia and pinches off a food vacuole
- vacuole fuses with a lysosome containing hydrolytic enzymes that will
digest the particle
2. pinocytosis:-
fluid droplets of extracellular fluid are incorporated into small vesicles
the process is not discriminating. the cell takes in all solutes dissolved in the
droplet
3. receptor-mediated endocytosis:-
- cells have receptors for certain molecules on their surface. when these
receptors encounter t molecule, they bind tightly to it. the complex of the
molecule and its receptor is then engulfed by endocytosis.
- a molecule that binds to specific receptor site of another molecule is called
a ligand.

13.  Exocytosis:-
The movement of material out of the cell
via membranous vesicles

14. Modification
apical lateral basal

15. 1. Apical surface
its tissue of cell membrane on toward the lumen,
there are many examples of apical
- stereocilia
- cilia
- flagella
- microvilli

16. Its function is
increase the cells surface area, facilitating the
movement of molecules into and out to the cell
Its can be found in
the lining of the epididymis

17. Its function is
Its can be found in
trapping the materials to protect them
the lining of the trachea ( windpipe)

18. Its function is
Its can be found in
reflecting cytoplasmic movement that will
increase the total surface area of cells
kidney and intestines

19. Its function is
Its can be found in
it concerned with movement
in some certain eukaryotes
EX. sperms in humans

20. 2.lateral
it is a kind of protein which joins between
adjacent cells within epithelium
these proteins have four types of junction:
• tight junction
• gap junction
• adherens junction
• desmosome

21. to form seal that prevents the flow of materials
between epithelial cells in either direction.
- help prevent the integral membrane proteins of
the apical surface from being transferred
epithelial cells in general, brain cells
Function:
Examples

22. permit the rapid exchange between
cells of molecules with small diameters
Function:
Examples
they are relevant in signal
transfers in the brain

23. unction provide strong mechanical
attachments between adjacent
cells (provide for firm adhesion of
one cell to its neighbors )
Function:
Examples
present in narrow bands connecting
adjacent cells or discrete patches
holding the cells together

24. desmosome provide firm adhesion
among the cells
Function:
Examples
Skin cells

25. 3- Basal
its a friction of the plasma membrane at the
basal side, which faces the underlying
connective tissue
Example of Basal
polarity
Basal lamina

26. polarity
in cells, polarity refers to the asymmetric
organization of different aspects of the cell
including the cell surface, intracellular
organelles and the cytoskeleton

27. Basal Lamina
Basal Lamina acts as base where the cells in
the body can grow. It links cells together and
underlies connective tissue.