Ligand- and voltage-gated channels would not be needed in cells that are attached to each other by:
a. tight junctions
b. gap junctions
c. desmosomes

Tight junctions

Explanation:

Many cells in the tissues are connected to each other and also to the extracellular matrix at some specialized points of contact called as the cell junction. They can be classified into the following types-

1.  Tight Junctions

2. Communicating Junctions

3. Anchoring Junctions

1. Tight Junction: They are also named as zonula occludens and are mediated by two trans membrane proteins namely claudins and occludins. Claudins and occludins interact with each other in such a way that they make the closest contact between the adjacent cells and likewise prevent the passage of any molecules and or ions across the epithelial layer in the spaces present between the cells.

2.  Gap Junction: Gap junctions are a type of the communicating junctions which serves as direct connections between the cytoplasm of the different cells. They also act as a channel which allows the inorganic ions, signal molecules, water soluble molecules and many other molecules thus coupling the cells both electrically and metabolically.

3. Desmosomes: Desmosomes are a type of anchoring junctions which are button like points of intercellular contact which helps in bonding the neighboring cells together. They bear a dense cytoplasmic plaque which is responsible for the connection of the cytoskeleton to the transmembrane linker proteins thus responsible for the connection of cell-cell.

Since tight junctions do not permit the movement of any molecules from one side of the membrane to the other side, voltage and ligand gated channels would not be required in these junctions.

answer:

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explanation:

08: 21

read the excerpt from "the tell-tale heart.”

object there was none. passion there was none. i loved the old man. he had never wronged me. he had never given me insult. for his gold i had no desire. i think it was his eye! yes, it was this! he had the eye of a vulture—a pale blue eye, with a film over it. whenever it fell upon me, my blood ran cold; and so by degrees—very gradually—i made up my mind to take the life of the old man, and thus rid myself of the eye forever.  

read the excerpt from "the black cat.”

beneath the pressure of torments such as these, the feeble remnant of the good within me succumbed. evil thoughts became my sole intimates—the darkest and most evil of thoughts. the moodiness of my usual temper increased to hatred of all things and of all mankind; while, from the sudden, frequent, and ungovernable outbursts of a fury to which i now blindly abandoned myself, my uncomplaining wife, alas! was the most usual and the most patient of sufferers.

by revealing the narrator’s deepest thoughts, the author