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function of sclerenchyma

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Question:what is a sclerenchyma cell? and what are the functions? are there any unique functions of a sclerenchyma cell? a picture of a sclerenchym would help too :) thanks

Answers:Sclerenchyma Mature sclerenchyma cells are dead and have secondary cell walls thickened with cellulose and usually impregnated with lignin. In contrast to collenchyma, which is pliable, sclerenchyma is elastic. The cell cavity or lumen is very small or it may disappear completely. There are two types of sclerenchyma cells, namely sclereids and fibres. Sclereids: The cells are irregular in shape. The cell walls are thick, hard and lignified which makes the lumen very small. Simple pits (canals) are found in the thickened cell walls and link adjacent cells. Sclereids are commonly found in fruit and seeds. Fibres: The cells are needle-shaped with pointed tips, thick walls and rather small lumen. Secondary cell walls, impregnated with, are formed. Simple pits are also present. Fibres are abundant in the vascular tissue of angiosperms, i.e. flowering plants. Functions: sclerenchyma is an important supporting tissue in plants, sclereids are responsible for the hardness of date seeds and the shell of walnut, fibres probably play a role in the transport of water in the plant, starch granules are stored in the young, living fibres. Photos in second link.

Question:

Answers:Sclerenchyma cells function in support of the plant. They contain a thick secondary wall containing lignin. For all intent and purpose these cells function best when dead.

Question:or is it next to the vascular bundle? Anyway I have a picture of a cross section of a diocot stem showing the vvascular bundle, next to the phloem is some sclerenchyma, my notes say that sclerenchyma is meant for providing support for mature plants or seed coats. Why is there sclerenchyma in the vascular bundle, is sclerenchyma also found here? Is this what it's talking about when it says sclerenchyma provides support, as it is next to the vascular bundle, what's happening here? I am just a bit confused thanks allot!

Answers:Sclerenchyma cells function in structural support of the stem and protection of the vascular bundles. Sclerenchyma cells are small and posses tough, thick cell walls. These walls are often impregnated with lignin, a highly branched polymer that makes cell walls more rigid. Mature sclerenchyma cells can not elongate and are found in regions of the plant that have stopped growing in length. At maturity sclerenchyma cells may actually be dead.

Question:please help

Answers:Sclerenchyma cells are single cells or groups of connected cells whose principal function is thought to be mechanical support of plants or plant parts. They are found in the stem, the roots (thick rigid cellular layers), and in the vascular bundles of the leaves. Sclerenchyma cells have thick secondary walls and may or may not remain alive when mature. They vary greatly in form and are of widespread occurrence in vascular plants. Two general types, sclereids and fibers, are widely recognized, but since these transform from one form to another through a series of stages or forms that involve partial transitions, the distinction is sometimes arbitrary.

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CARBONITE DISAMBIGUATION ~ FLEXING THE CORTEX :THE CEBRAL CORTEX nuedutainment.comyr.com The mass of primary tissue in roots and stems extending inward from the epidermis to the phloem. The cortex may consist of one or a combination of three major tissues: parenchyma, collenchyma, and sclerenchyma. In roots the cortex almost always consists of parenchyma, and is bounded, more or less distinctly, by the hypodermis (exodermis) on the periphery and by the endodermis on the inside. THE EXECUTIVE SYSTEM Is thought to be heavily involved in handling novel situations outside the domain of some of our 'automatic' psychological processes that could be explained by the reproduction of learned schemas or set behaviors. Psychologists Don Norman and Tim Shallice have outlined five types of situations in which routine activation of behavior would not be sufficient for optimal performance 1. Those that involve planning or decision making. 2. Those that involve error correction or troubleshooting. 3. Situations where responses are not well-rehearsed or contain novel sequences of actions. 4. Dangerous or technically difficult situations. 5. Situations that require the overcoming of a strong habitual response or resisting temptation. The executive functions are often invoked when it is necessary to override responses that might otherwise be automatically elicited by stimuli in the external environment. For example, on being presented with a potentially rewarding stimulus, such as a tasty piece of chocolate cake, a person might have the ...