Final answer:
The movement of leaves of a sensitive plant is a rapid folding response to touch (thigmonasty) for defense, while the movement of a shoot towards light (phototropism) is a growth response for better light absorption.
Step-by-step explanation:
Two Distinct Plant Movements
The movement of leaves of a sensitive plant, such as Mimosa pudica, differs from the movement of a shoot towards light in several ways. Firstly, the movement of sensitive plant leaves is a rapid folding response to touch, called thigmonasty or seismonasty, which serves as a defense mechanism to deter herbivores or protect the plant from harm. In contrast, the movement of a shoot towards light, known as phototropism, is a growth response where the shoot bends towards the light source to maximize light absorption for photosynthesis.
Secondly, the mechanism behind these movements also differs. The sensitive plant responds to touch by rapidly changing the water pressure in its cells, leading to the folding of the leaves. This is an immediate and non-directional movement that does not involve growth. On the other hand, phototropism is a directional growth response regulated by the plant hormone auxin, which accumulates on the side of the shoot that receives less light, causing the cells to elongate more on that side and the shoot to bend towards the light.