Question

In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates:

Please choose the correct answer from the following choices, and then select the submit answer button.


-either cellular response or signal transduction.

-termination.

-signal transduction.

-receptor activation.

Answer 1

The initial phosphorylation step after a ligand binds to a receptor best demonstrates signal transduction, a key process in cellular communication leading to various types of cellular responses.

Step-by-step explanation

When a ligand binds to a receptor on the cell surface, it initiates a change in the receptor's structure, often resulting in the receptor being phosphorylated by enzymes called kinases. This phosphorylation is a critical step in signal transduction, which refers to the process of conveying the signal through the cell via various intracellular molecules. These phosphorylated proteins can either become activated or inactivated, leading to a cascade of further signal transmission inside the cell, involving other molecules and second messengers like cAMP and Ca2+. Eventually, this cascade results in a cellular response, such as changes in metabolism, gene expression, or even cell death. The concept of signal transduction is important because it ensures that cells respond appropriately to signals, whether they originate from inside the body or the external environment.