2. Discussion Matter
2. BASIC MECHANISM OF TRANSPORT
3. PASSIVE TRANSPORT
4. SPECIAL TYPE OF PASSIVE TRANSPORT
5. ACTIVE TRANSPORT
6. SPECIAL TYPE OF ACTIVE TRANSPORT
7. MOLECULAR MOTORS
8. APPLIED PHYSIOLOGY
- Through the transport mechanism across cell
+ The cell in the body must be supplied with essential
+ Must get rid many unwanted substances.
- Essential: water, nutrients, electrolytes, etc.
- Unwanted: waste products, CO2, etc.
Who is the actors for this transport?
LIPID & PROTEIN
6. Passive transport?
- The transport of substances along the
concentration gradient OR electrical gradient OR
BOTH (electrochemical gradient).
- Higher concentration lower concentration
- Does not need energy
- Downhill movement/ diffusion.
7. 2 Diffusion
1. Simple Diffusion
- Simple diffusion through lipid layer
- Simple diffusion through protein layer
2. Facilitated Diffusion
- Facilitated or carrier-mediated diffusion
8. Simple Diffusion Through Lipid Layer
- Directly proportional to the solubility of
substances in lipids.
- Lipid layer of the cell membrane is
permeable only to lipid soluble
substances. (O2, CO2, alcohol)
10. Simple Diffusion Through Protein
- Electrolytes diffuse through protein layer
- Protein layer is permeable to water-soluble
1. Protein Channel/Ion Channel
lined up by the integral protein
Form the channel for diffusion of water.
2. Type of Protein/Ion Channel
- The channel are named after the ions
which diffuse through this channel.
- Ex: sodium channel, potassium channel,
The characteristic features of protein
channel is selective permeability. Each
channel can permit only 1 type ion pass
a. Voltage gated channels -> open whenever there
is a change in the electrical potential. Ex:
b. Ligand gated channels -> open in the presence of
some hormonal substances (ligands).
c. Mechanical gated channels -> opened by some
mechanical factors. Ex: receptor cells.
14. Facilitated or Carrier-Mediated
The type of diffusion by which the water
soluble substances having larger
molecules are transported through the cell
membrane with the help of carrier protein.
For glucose and amino acid?
15. Factors Affecting Rate of Diffusion
Permeability of the Cell Membrane
Concentration Gradient/Electrical Gradient of the
Substances across the Cell Membrane
Solubility of the Substance
Thickness of the Cell Membrane
Size of the Molecules
Size of the Ions
Charge in the Ions
16. SPECIAL TYPE OF PASSIVE
Bulk Flow -> diffusion of large quantity of substances :
high pressure region low pressure region.
Ex: exchange gases across the respiratory membrane in
Filtration -> movement of water & solutes: high
hydrostatic pressure area low hydrostatic area.
Osmosis -> movement of water/any other solvent:
lower concentration area high concentration solute.
18. - Osmosis through semipermeable membrane.
- Osmotic Pressure -> pressure created by the solutes in a
- Reverse Osmotic Pressure -> process in which
water/other solvent flows in reverse direction.
- Colloidal Osmotic Pressure -> osmotic pressure exerted
by colloidal substances.
- Oncotic Pressure -> osmotic pressure exerted by
colloidal substances (protein) of the plasma. It is about
19. 2 type osmosis:
1. Endosmosis -> movement of water into
2. Exosmosis -> movement of water out
20. ACTIVE TRANSPORT
The movement of substances against the
It is uphill transport.
It is required energy
21. Active Transport vs Facilitated Diffusion
Active Transport Facilitated Diffusion
Carrier protein need energy Carrier protein does not need
The substances are transported
against the concentration/
The substances are transported
along the concentration/
22. Carrier Protein of Active
- Carries only 1 substances in a single direction.
- Uniport pump.
Symport or Antiport
- Symport ->transport 2 different substances in the same
- Antiport -> transport 2 different substances in opposite
23. Mechanism of Active Transport
Comes near the cell membrane
Combines with the carrier protein
Forms substances-proteins complex
Complex moves towards the inner surface of the cell
Released from the carrier proteins
Same protein moves back to outer surface to transport
27. Sodium-Potassium Pump
Sodium 7potassium transported across the cell
Na+-K+ ATPase pump
Transport sodium: insideoutside cells
Transport potassium: outsideinside cells
Present in all cells of the body
Responsibility -> distribution of sodium & potassium
ions across the cell membrane
-> development of resting membrane
29. Transport of Calcium Ion
Actively transported from inside to outside of the cell by
Operated by a separate carrier protein.
Energy from ATP by the catalytic activity of ATPase.
Also present in some organelles. For move calcium into
30. Transport of Hydrogen Ions
Actively transported by hydrogen pump.
Energy from ATP.
The pump present in Stomach & Kidney.
31. SECONDARY ACTIVE TRANSPORT
Transport of substance with sodium ion.
When sodium is transported, another substance also
transported. Either in same direction or opposite.
2 type: Cotransport & Counter transport
33. Sodium Cotransport
Substance is transported by symport along with sodium.
Movement energy from breakdown of ATP.
Released energy utilized form movement another
Substances: glucose, amino acid, chloride, iodine, iron,
35. Sodium Counter Transport
Substances are transported in exchange for sodium ion
Various counter transport:
+ sodium-calcium counter transport
+ sodium-hydrogen counter transport
+ other counter transport system
Mechanism by which macromolecules enter the cell.
It cannot pas the membrane by passive or active transport
pinocytosis-> cell drinking, by which macromolecules like bacteria
and antigen are taken into cells.
39. Phagocytosis-> Cell eating, particle larger than
macromolecules are engulfed into the cells.
Larger bacteria, larger antigen, other
larger foreign body.
40. Receptor-mediated Endocytosis-> transport of
macromolecules with the help of a receptor protein.
->clathrin: receptor protein in surface od cell
-> receptor-coated pit: clathrin + pits cell
Process by which the substances are expelled out from the
The substances are extruded from cell without passing through
the cell membrane.
Role of Calcium? Calcium ion enter the cell and cause
44. MOLECULAR MOTOR
Protein based molecular machine that perform
intracellular movement in response to spesific stimuli.
-transport of synaptic vesicle containing neuro transmitter
from the nerve cell body to synaptic terminal.
-role in cell division by pulling the chromosomes
Transport of viruses & toxins to the interior of the cell for its