Notes for class X Transport con't

Pumping mechanism  of heart ------First the blood enters in left and right atria from lungs and body respectively .Now the walls of atria contact and the blood moves to respective ventric;les through valve . When the thick walls of ventricles contract the oxygenated blood from left ventricle moves to the whole body through aorta and de -oxygenated blood moves to lungs through pulmonary artery.


How water rises in the plant There are two major forces involved in ascent of cell sap or rising of water:-   

(1) Root pressure The concentration of water if more in the soil and less in the root cells so this change in the concentration pushes the water into the roots through osmosis .

(2) In order to rise above against gravity the plant needs high pressure which is provided  by transpirational pull .the stomata loose water in the process of transpiration which causes a suction pressure allowing the water to be pulled up without spending any energy.

How the food moves in the plant:-
Movement of food in the plant from region where it is produced to the region where it is needed is called translocation .This process unlike movement of water requires energy in the form of ATP .Water only moves upwards whereas food moves from source(region where it produced) to sink (region of need) in both the directions .The ATP molecule helps the sucrose or other food to move to sieve tubes  this makes the osmotic pressure increase and allows water to  move into these cells .the high pressure in this zone makes the food to travel to the region of low pressure i.e. where food is needed .

In spring season the food stored  in the tubers underground travels to the buds for flowering so food can travel in any direction with the help of energy.