BOTANY
CYTOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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plasma membranes are in actual contact
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the space between plasma membranes is about twenty nanometers
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between plasma membranes there is an electron-dense zone
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the space between plasma membranes is about three nanometers
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the cell contact is able to transmit nerve impulse (activation or inhibition) from one cell to the other
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Detailed explanation-1: -Gap junctions connect the cytoplasms of two adjacent cells through nonselective channels. Connections through adjacent cells are at locations where the gap between cells is only 2–3 nm. This small gap is where the term “gap junction” originated.
Detailed explanation-2: -Gap junctions are clusters of intercellular channels that allow direct diffusion of ions and small molecules between adjacent cells. The intercellular channels are formed by head-to-head docking of hexameric assemblies (connexons) of tetraspan integral membrane proteins, the connexins (Cx) (Goodenough et al. 1996).
Detailed explanation-3: -Many cells in tissues are linked to one another and to the extracellular matrix at specialized contact sites called cell junctions. Cell junctions fall into three functional classes: occluding junctions, anchoring junctions, and communicating junctions.
Detailed explanation-4: -Gap junctions are formed by a group of (usually six)proteins, called connexins, that span the cell membrane and unite with connexins of a neighboring cell, forming a channel called a connexon (see Figure 5-1).