1. Hormones in multicellular organisms regulate and coordinate various physiological processes, ensuring homeostasis and adaptive responses to environmental changes. In plants, hormones like auxins, gibberellins, and cytokinins are synthesized in specific tissues such as meristems. Transport occurs thrRead more

    Hormones in multicellular organisms regulate and coordinate various physiological processes, ensuring homeostasis and adaptive responses to environmental changes. In plants, hormones like auxins, gibberellins, and cytokinins are synthesized in specific tissues such as meristems. Transport occurs through vascular tissues, with auxins exhibiting polar movement. In animals, hormones are synthesized in specialized glands and transported through the bloodstream to target cells. These chemical messengers initiate diverse responses, including growth, metabolism, and stress adaptation. Overall, hormones are key mediators in the control and coordination of biological functions, allowing multicellular organisms to adjust to internal and external stimuli for survival and proper functioning.

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  2. The speed of movement varies in different plant responses. The sensitive plant (Mimosa pudica) exhibits rapid leaf folding within seconds when touched. Sunflowers showcase slower movements, as they track the sun's position over the day, a process known as heliotropism. Growth-related movements, likeRead more

    The speed of movement varies in different plant responses. The sensitive plant (Mimosa pudica) exhibits rapid leaf folding within seconds when touched. Sunflowers showcase slower movements, as they track the sun’s position over the day, a process known as heliotropism. Growth-related movements, like phototropism or gravitropism, occur gradually over hours to days. These responses involve differential cell elongation. While the sensitive plant shows rapid, reversible movements for defense, sunflowers demonstrate slower, tracking motions for optimal light absorption, and growth-related movements ensure overall plant adaptation to environmental stimuli with varying time scales.

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  3. The directional movement of a seedling, such as bending towards light (phototropism), is associated with differential growth rates. Cells on one side elongate more than those on the other, causing curvature. This growth response allows the plant to optimize light absorption. If growth is impeded, thRead more

    The directional movement of a seedling, such as bending towards light (phototropism), is associated with differential growth rates. Cells on one side elongate more than those on the other, causing curvature. This growth response allows the plant to optimize light absorption. If growth is impeded, the seedling may fail to exhibit the desired directional movement. Factors like insufficient light, physical barriers, or hormonal imbalances can hinder growth. Impeded growth may lead to stunted development, compromised adaptation to environmental stimuli, and decreased overall fitness, as the plant cannot effectively adjust its orientation to optimize resources.

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  4. The sensitive plant, Mimosa pudica, lacks nervous and muscle tissue but exhibits touch-sensitive leaf movements. Rapid leaf folding is triggered by a process called thigmonasty. Specialized cells, called pulvini, are concentrated at the base of leaflets and actively pump potassium ions in response tRead more

    The sensitive plant, Mimosa pudica, lacks nervous and muscle tissue but exhibits touch-sensitive leaf movements. Rapid leaf folding is triggered by a process called thigmonasty. Specialized cells, called pulvini, are concentrated at the base of leaflets and actively pump potassium ions in response to touch. This ion movement results in a rapid loss of turgor pressure, causing cell collapse and reversible leaf folding. The response is thought to be a defense mechanism against herbivores. While lacking a nervous system, the plant employs these specialized cells and ion movements to detect touch and initiate rapid leaf movements in response to mechanical stimulation.

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  5. In the sensitive plant (Mimosa pudica), the point of touch and the point where movement occurs are not the same due to the propagation of an action potential. When one part of the plant is touched, specialized cells called pulvini at the base of leaflets detect the stimulus. The action potential theRead more

    In the sensitive plant (Mimosa pudica), the point of touch and the point where movement occurs are not the same due to the propagation of an action potential. When one part of the plant is touched, specialized cells called pulvini at the base of leaflets detect the stimulus. The action potential then travels along the length of the leaflet before reaching the pulvinus. Movement occurs at the pulvinus, leading to rapid leaf folding. This delay between the point of touch and the actual movement allows the plant to localize the response to the specific area of disturbance, optimizing its defensive reaction against potential threats.

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