cell structure


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cell structure

see CELL.

cell structure

common intracellular features (nucleus, cytoplasm, cell membrane) and organelles (endoplasmic reticulum, lysosomes, mitochondria, microtubules, Golgi apparatus) which facilitate specialist function (see Table 1)
Table 1: Cell organelles
StructureCharacteristic
Cell membraneBimolecular lipid and protein membrane that surrounds the cell
• Bi-layer of non-polar lipid molecules (phosphatidylcholine, phospharidylethanolamine, cholesterol) that acts as a barrier to water and hydrophilic solutes
• Proteins:
  • Structural proteins

  • Protein pumps that actively transport ions such as sodium out of the cell

  • Carrier proteins that carry molecules such as glucose into the cell

  • Ion channel proteins, such as sodium ion channels in nerve fibres to which molecules of local anaesthetic attach to prevent the passage of the pain-inducing nerve impulse

  • Receptor proteins, such as insulin receptors which facilitate the passage of glucose into the cell

  • Immunoglobulin proteins, which form part of the immune response mechanism

  • Enzyme proteins, such as alkaline phosphatase

Cell cytoplasmThe gel-like matter contained within the membrane envelop:
• Contains and supports specialized organelles, including the cell nucleus, endoplasmic reticulum, the Golgi apparatus, mitochondria and lysozomes
• Stores substances (glycogen and lipids)
• Synthesizes and metabolizes essential substances (amino acids, fatty acids, monosaccharides)
• Synthesizes and translates protein
• Contains microtubules which help maintain the form of the cell and form intercommunication channels between organelles
Cell cytoskeletonA complex network of structural elements (microtubules, intermediate filaments and microfilaments) which determine the shape of the cell, its ability to move and its response to external stimuli
Cell nucleusPresent in all eukaryotic cells capable of mitosis
Contains the cell genome (DNA) and the means of replication and transcription of RNA
Separated from the cytoplasm by the nuclear envelop (which disappears during mitosis and meiosis)
Contains the nucleolus, where ribosomes are synthesized
Intercellular connectionsThere are two types of intercellular connections: tight junctions and gap junctions
Cell adhesion molecules (CAMs)Structures (receptor integrins, immunoglobulin adhesion molecules, Ca+-dependent cadherins and carbohydrate-binding selectins) within the cell membrane that bond to laminins within the extracellular matrix to attach adjacent cells to one another and to the basal membrane
References in periodicals archive ?
It is also of interest to establish whether the cell structure is open or closed.
ob) revealed on Thursday that the company has filed a United States Patent entitled "New Solar Cell Structure with Increased Efficiency".
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KTM's proprietary formulation adds mineral nucleating agents and biodegradable modifiers to create a flexible foam with a controlled dosed cell structure.
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One of T[eth]4's key mechanisms of action is its ability to regulate the cell-building protein, actin, a vital component of cell structure and movement.