Question

List all cell responses to a primary chemical messenger and all the signal transduction mechanisms involved in bring that message to the cell.

Answer 1

Answer : The signal from the ligand is passed on to the receptor. Here the chemical messengers relay the signal which concludes in receving the response. The sequence of molecules that relays the signal inside the cell is known as signal transduction. The mechanisms involved are:

• Binding initiates a signal pathway : Proteins are the molecules that relay on a signal. The signal transduction pathway amplifies the signal so that activation of molecules take place.
• Phosphorylation : An enzyme called kinase is used here. The kinase helps in catalysing the reaction to convert dephosphorylated protein to phosphorylated protein. During this process three ATP molecules are converted to two ADP molecules.
• There is another enzyme called phosphatase which converts phosphorylated protein to dephosphorylated protein.
• Calcium ions and Cyclic AMPs also helps in the signal transduction mechanism.