Absorption and Transport of Solutes MCQ - Practice Questions with Answers

• The process of absorption can be demarcated into two main phases.
• In the first phase, an initial rapid uptake of ions into the ‘free space’ or ‘outer space’ of cells – the apoplast, is passive. 
• In the second phase of uptake, the ions are taken in slowly into the ‘inner space’ – the
• symplast of the cells. 
• The passive movement of ions into the apoplast usually occurs through ion-channels, the trans-membrane proteins that function as selective pores. 
• On the other hand, the entry or exit of ions to and from the symplast requires the expenditure of metabolic energy, which is an active process. 
• The movement of ions is usually called flux; the inward movement into the cells is influx and the outward movement, efflux.

Translocation of Solutes

• Mineral salts are translocated through xylem along with the ascending stream of water, which is pulled up through the plant by transpirational pull. 
• Analysis of xylem sap shows the presence of mineral salts in it. 
• Use of radioisotopes of mineral elements also substantiate the view that they are transported through the xylem.