Class 10/Specimen Paper
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
BioNotesBioNotesCreated by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Online
ICSE Suggested Specimen Paper Based Preparation Guide
Why does a freshly picked lettuce leaf wilt when left in the sun, but become crisp again when placed in cold water?
If you add a large amount of salt to the soil around a plant, it will eventually die. Explain this phenomenon using the principles of osmosis.
Odd One Out: Imbibition, Diffusion, Osmosis, Active Transport.
Scenario: A balsam plant shoot is placed in a beaker of water with a layer of oil on top. What is the purpose of the oil layer in this experiment, which is designed to demonstrate the ascent of sap?
The Challenge of Saline Soils in Agriculture
In many coastal and arid regions, soil salinity is a major agricultural problem. High concentrations of salt in the soil create a hypertonic environment. This makes it extremely difficult for crop plants to absorb water through their roots via osmosis. In fact, the osmotic potential of the soil water can be so low that it draws water out of the plant roots, leading to plasmolysis, wilting, and crop failure. To overcome this, scientists are working on developing salt-tolerant crop varieties that can either exclude salt from their roots or accumulate it in specific tissues to maintain a favorable water potential gradient for water absorption.
Assertion (A): The ascent of sap in tall trees is primarily due to transpirational pull. Reason (R): The cohesive and adhesive properties of water create an unbroken, continuous water column in the xylem.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A). (b) Both (A) and (R) are true but (R) is not the correct explanation of (A). (c) (A) is true but (R) is false. (d) (A) is false but (R) is true.
Root pressure is a relatively weak force and is often absent during the day. How then can a plant ensure a continuous supply of water to its leaves, especially at the top of a very tall tree, on a hot, sunny day?