THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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They trigger a second cellular response
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They are the second molecule in a phosphorylation cascade
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Signaling molecules are considered the first messenger
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They are the second molecule that dephosphorylates proteins
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Detailed explanation-1: -The term second messenger was coined upon the discovery of these substances in order to distinguish them from hormones and other molecules that function outside the cell as “first messengers” in the transmission of biological information.
Detailed explanation-2: -The activation of multiple target enzymes by a single second messenger molecule further amplifies the signal. Second messengers are not only produced in response to extracellular stimuli, but also in response to stimuli from within the cell.
Detailed explanation-3: -Second messengers are molecules that relay signals received at receptors on the cell surface-such as the arrival of protein hormones, growth factors, etc.-to target molecules in the cytosol and/or nucleus.
Detailed explanation-4: -What are second messengers? Signals received by receptors at the cell surface or, in some cases, within the cell are often relayed throughout the cell via generation of small, rapidly diffusing molecules referred to as second messengers.
Detailed explanation-5: -G-proteins activate the second messenger (cyclic AMP), triggering the cellular response. Response to hormone binding is amplified as the signaling pathway progresses.