Absorption by Roots — Part 1: Diffusion, osmosis and plasmolysis: visual lesson, ICSE Class 10 Biology (Science Paper 3)

Lesson

Absorption by Roots and the Ascent of Sap

Part 1 — the physical processes that move water into and out of cells.

In this lesson you will

Distinguish imbibition, diffusion and osmosis with examples, and explain osmotic pressure
Describe the potassium permanganate, thistle funnel and potato osmoscope experiments
Explain turgidity, flaccidity and plasmolysis, and predict what happens to cells in hypotonic, isotonic and hypertonic solutions

Concept

Imbibition is the absorption of water by dry solid materials, which then swell.

Table of three examples of imbibition
Example	What happens
Dry seeds soaked overnight	Swell and soften; germination begins
Raisins in water	Plump up
Wooden doors in the rains	Swell and jam

Diagram

Diffusion is the movement of molecules from a region of higher concentration to lower concentration until they are evenly spread.