Question

Explain the terms passive and active transport and hypo/iso/hyper-osmotic concentrations. How is concentration related to transport type? Explain in terms of effects on animal and plant cells.

Answer 1

Hi Answer:

Active transport

Active transport is also known as the movement against the gradient. Active transport of substances across the membrane was first described by the German physiologist Emil du Bois-Reymond in 1848. It can be defined in simple words that the movement of molecules across a membrane from the region of higher concentration to the region of lower concentration. Example of active transport is the absorption of glucose in human gastro intestine. The active transport needs energy in the form of ATP. Active transport can be divided into two subsequent types i.e. (i) Primary active transport, which needs ATP for movement and (ii) secondary active transport, this type uses an electrochemical gradient for the molecule movement.

Passive transport

It is the movement of molecules or ions across the membrane. The passive transport didn’t require any energy. The transport rate across the membrane depends on the permeability of the membrane and the permeability of the membrane depends on the lipid and protein composition of the cell membrane. The example of passive transport is simple diffusion where the molecules from higher concentration simply diffuse toward the lower concentration. There are 4 types of passive transport i.e. simple diffusion, facilitated diffusion, filtration, and osmosis.

Hypoosmotic concentration

The hypoosmotic concentration means the low concentration of the solute in a solution when compared with the other solution who have higher solute concentration. Example: The cell from freshwater animal placed in the concentrated salt water, then that cell is said to be hypoosmotic to the water.

Isoosmotic concentration

The concentration of solute in both solution is similar. Example: in such condition, there is no osmotic pressure on the cell walls

Hyperosmotic concentration

The hyperosmotic concentration means the high concentration of the solute in a solution when compared with the other solution who have lower solute concentration. Example: The cell from higher saltwater animal placed in the fresh water, then that cell is said to be hyperosmotic to the water.

How concentration related to transport type explain in terms of effects on animal and plant cells.

The transport of molecules is always related to the concentrations of the molecules because the type of transport depends on the concentration, for example, the solute concentration in a solution is higher then the transport will be the passive where the molecules will move along the concentration gradient there will be no energy required and in another way when concentration is low then the transport of the molecules took place by active transport where the ATP is used for the movement of molecules. The fact is similar for both animal cells and plant cell. In case of the animal cell when the concentration of the solute varies then the solution become hypo, hyper and isotonic and on the bases of the concentration the type of transport is selected. If the solution is hypertonic then the transport will be passive and if it is hypotonic then the transport will be active.