THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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they have receptors on the external surface of the cell membrane
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they have receptors in the cytoplasm of cells
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they can travel long distances
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they are found in primitive cells
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Detailed explanation-1: -Question: Which of the following provides the best evidence that cell-signaling pathways evolved early in the history of life ? Cell-signaling pathways are seen in “primitive” cells such as bacteria and yeast. Most signals in all types of cells are received by cell surface receptors.
Detailed explanation-2: -Answer and Explanation: The correct answer is option c) Plants, animals and bacteria share very similar signaling processes. The cell signaling is a conserved process and similar in all life forms.
Detailed explanation-3: -The discovery of cellular signaling dates back to 1855 when Claude Bernard described how certain ‘internal secretions’ of ductless glands, released into the bloodstream, can have effects on distant cells.
Detailed explanation-4: -Answer and Explanation: The receptor-ligand interaction is very transient and that is why after the induction of signal the ligand loose interaction with the receptor. So the correct answer is c. The molecule binds to a receptor protein, which changes the protein and triggers signal transduction.
Detailed explanation-5: -Direct signaling (also called juxtacrine signaling) involves communication between cells that are in direct contact with each other. This communication is often mediated by gap junctions in animal cells and plasmodesmata in plant cells. Autocrine singaling occurs when a ligand acts on the same cell that releases it.