Question

Identify 3 physical conditions that can optimize rate of diffusion of a gas across a membrane, and relate these to Fick’s Law of Diffusion. Please describe 3 ways animal respiratory systems have evolved in order to maximize the exchange of O₂ and CO₂ across their membranes.                                                                                                                                                               

Answer 1

ANS- 3 PHYSICAL CONDITION / FACTORS THAT OPTIMIZE RATE OF DIFFUSION ACROSS A MEMBRANE.

1. Surface area--> If the surface area is larger ,the movement of particles will be rapid across a membrane and high amount of particles will be move.

2.Distance-------->If Smaller the diffusion  distance is ,the lesser amount of time will be taken by the particles to travel more far.

3 Concentration difference/ gradient--> The rate of diffusion is rapid if there is a large difference in the concentration between the area the particles travel from and the area that it is moving to.

* Example- HUMANS->they are having alveoli in their lungs that having the adaptation of these factors 3 in order to obtain high oxygen . and to maintain the metabolism of a body.

** Fick,s Law--> According to fick,s law the rate of diffusion is proportional to both the surface area and concentration difference and it is inversely proportional to thickness of the membrane.

• The relationship between the rate of diffusion and the three factors is explained by the flick,s law .

EXPRESSION OF FLICK,S LAW-->

Diffusion rate $\alpha$ surface area x concentration gradient / membrane thickness.

*Conditions where rate of diffusion get double-

• When the exchange membrane thickness is reduced or getting half the diffusion rate become double.
• Concentration difference / concentration gradient get double the diffusion rate get double.
• Double the surface area is double the diffusion is.

*3 WAYS ANIMAL RESPIRATORY SYSTEM EVOLVED IN TO MAXIMIZE O2 AND CO2 EXCHANGE.

1. short diffusion distance-> The epithelia in alveoli (respiratory system) and villi ( small intestine) are thin.

• The thickness of blood capillaries is one cell thick.

2. large surface area-->The presence of alveoli in respiratory system to increase the surface area for the exchange of gases .

3. efficient molecule transport system-->

• The network of blood capillaries that surrounds each alveolus in the lungs.
• the network of blood capillaries in each villus in the small intestine.