Signal transduction
Cellular mechanism that converts a stimulus into a specific cellular response. Signal transduction starts with a chemical or physical signal to a receptor, and ends with a change in cell function.
A signal transduction in biology, is a cellular mechanism. It converts a stimulus into a specific cellular response.
Signal transduction starts with a chemical or physical signal to a receptor, and ends with a change in cell function. Receptors are in the cell membrane, with part of the receptor outside and part inside the cell. The chemical signal binds to the outer portion of the receptor, changing its shape. This causes another signal inside the cell.
Sometimes there is a cascade of signals within the cell. With each step of the cascade, the signal can be amplified, so a small signal can result in a large response. Eventually, the signal creates a change in the cell, either in the expression of the DNA in the nucleus or in the activity of enzymes in the cytoplasm. Most often, ordered sequences of biochemical reactions inside the cell are involved. These are carried out by enzymes and linked through second messengers.
So a "second messenger pathway" is produced. These things usually happen quickly, sometimes very quickly. They may last from milliseconds (in the case of ion flux) to days for gene expression.