NCERT Solution for Class 10 Science Chapter 7
Control and Coordination
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Exercises Questions
Page No-126
Questions No-12
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
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The manner in which movement takes place in a sensitive plant (Mimosa pudica) and the movement in our legs is fundamentally different. These differences are related to the mechanisms and purposes of movement in each case:
Movement in a Sensitive Plant (Mimosa pudica):
1. Type of Movement: The sensitive plant exhibits a phenomenon called “thigmonasty” or “thigmotropism.” When touched or exposed to mechanical stimulation, the leaflets of a sensitive plant fold or collapse.
2. Mechanism: This rapid leaf-folding response is primarily due to changes in turgor pressure within specialized motor cells in the leaflets. When touched, the plant rapidly loses turgor pressure in the affected cells, causing the leaflets to droop or close.
3. Purpose: The purpose of this rapid movement is not for locomotion but rather as a defense mechanism. The plant uses thigmonastic movement to reduce its exposure to potential threats, such as herbivores or environmental stressors.
Movement in Our Legs:
1. Type of Movement: In humans and other animals, leg movement is primarily for locomotion and mobility.
2. Mechanism: Leg movement in humans is achieved through the coordinated contraction and relaxation of muscles and the movement of joints, such as the knee and hip joints. This complex process is controlled by the nervous system and is under conscious control.
3. Purpose: The primary purpose of leg movement is to enable humans to walk, run, jump, and perform various activities. Leg movement is essential for mobility, allowing individuals to navigate their environment and carry out daily tasks.
In summary, the key differences between movement in a sensitive plant and movement in our legs are related to the purpose, mechanism, and control of movement. The sensitive plant’s movement is a rapid, non-locomotor response triggered by mechanical stimulation, primarily serving a defensive purpose. In contrast, leg movement in humans is a controlled, locomotor process directed by the nervous system, enabling mobility and various physical activities.
The movement in a sensitive plant is facilitated by chemical control, while the movement in our legs is facilitated by nervous control.
Movement in sensitive plants:
1. The movement that takes place in a sensitive plant such as Mimosa pudica occurs in response to touch (stimulus).
2. For this movement, the information is transmitted from cell to cell by electrochemical signals as plants do not have any specialised tissue for conduction of impulses.
3. For this movement to occur, the plant cells change shape by changing the amount of water in them.
Movement in our legs:
1. Movement in our legs is an example of voluntary actions.
2. The signal or messages for these actions are passed to the brain and hence are consciously controlled.
3. In animal muscle cells, some proteins are found which allow the movement to occur.