Explain two roles of diffusion in human beings

a) Explain two roles of diffusion in human beings.  (4mks)

b i) Name the process through which a plant takes up some mineral ions against a concentration gradient.  (1mk)

  ii) State two factors that may affect the process named in b(i) above. (2mks)

c) Distinguish between haemolysis and plasmolysis. (1mk)

Answers

a)

• Absorption of digested food such as glucose and amino acids; into the blood stream;
  
• Exchange of respiratory gasses ie oxygen and carbon(iv) oxide; between the alveolus and blood capillaries;
  
• Excretion of nitrogenous wastes such as urea; from the blood capillaries into elimination site;
  

Any two  

b

i) Active transport;
ii) – Low oxygen concentration;
  – lowering temperature below optimum level;
 – Presence of enzyme inhibitors;                               

ANY TWO

c)

Haemolysis- A process by which red blood cells take up water from a solution of lower solute solution by osmosis till they burst. 

OWITTE

Plasmolysis – A process by which plants cell loss water to a solution of higher solute Concentration by osmosis and becomes flaccid;     

OWITTE