Passive Transport

Passive Transport

Passive transport is the fundamental movements of ions and other molecular substances within the cells without any external energy.

There are two types of transportation in our body viz. Active and Passive Transport, which are required to transport biochemical nutrients like water and oxygen to the cells.

In active transport, the molecules move against the concentration gradient, and thus requires chemical energy to transport the components from lower to higher concentrated area or body part.

Passive transport is the process of movement of the biochemical across the cell membranes and tissues without any of external energy. There are four types of passive transport like :

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


Diffusion is the movement of biogeochemical substances from an area of higher concentration to lower concentration. The difference in the concentration of the two areas is termed as concentration gradient and the process of diffusion continues till this gradient neutralizes.

Facilitated diffusion

Facilitated diffusion is a natural passive transportation of ions or molecules across the cell membrane through specific-transmembrane integral proteins. The molecules, which are large and insoluble requires a carrier substance for their transportation through the plasma membrane. This process does not require any cellular energy or external energy.


The cardiovascular system in the human body generates a hydrostatic pressure, which helps water and other soluble biochemical molecules to move across the cell membrane. This process is termed as filtration because the cell membrane permits only a substance which is soluble and could easily pass through the membrane’s pore.


In the process of osmosis, the water, and other molecules transport through the selectively permeable cell membrane. There are many factors that affect this movement or transport. One of the major factors is the cell having less negative water potential and other factors include the solute potential of a molecule and the pressure potential of a cell membrane.

There is a theory of conflict about the process of osmosis. Few biologists suggest that osmosis is an active transport and not passive transport.

Transport of biogeochemical because of concentration

The cells of different organs differ in their concentration level. Like, the concentration of oxygen molecules are high when present outside a cell and are low when inside a cell. The oxygen molecules are too small that they could easily permeate through the lipid bilayer. This entire process does not require energy.

To learn more about the difference between active and passive transport, visit Byju’s

Practise This Question

A plant that does not have roots cannot survive for long. Why?