Unit 4: Topic 2 - Introduction to Signal Transduction

Question 1

What are the components of a signal transduction pathway?

Answer 1

There are three essential components to a signal transduction pathway. The first one is reception, where the ligand, which is the signaling molecule that starts the signal transduction pathway, binds to a receptor. The second part is transduction. The binding of the ligand to the receptor causes a cellular signal to go off, and transduction uses chemical messengers to relay that signal through the cell. The third part is the cellular response, which is the final result of the signal transduction pathway. diagram

Question 2

Example of Signal Transduction Pathway - Google Docs

Answer 2

The effect of the ligand (which is the epidermal growth factor) binding to the receptor is the increased transcription of genes promoting cell growth and division

Question 3

What are phopshorylation cascades and how do they relate to the signal transduction pathway?

Answer 3

A phosphorylation cascade is when the phosphorylation of a protein triggers the phosphorylation of another protein, and so on. Phosphorylation is when a phosphate group is removed from a molecule to another molecule. Phosphorylation cascades are essential)
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Question 4

How does the signal transduction pathway start?

Answer 4

The signal transduction pathway starts when a ligand, which may be a peptide, small chemical, or protein, binds to the ligand-binding domain of a receptor protein in the target cell. The cell receptor fits with the ligand in a one-to-one relationship; the ligand can only bind to one specific receptor and vice versa.

Question 5

What is one commmon example of a receptor protein in eukaryotes?

Answer 5

A common receptor protein in eukaryotes are G protein-coupled receptors.

Question 6

What are signaling cascades?

Answer 6

Signaling cascades relay the signal from the receptor to the targets in the cell. They often do this by amplifying the signal, activating multiple messengers inorder to achieve the aprropriate cell reponse.

Question 7

What happens to the domain of a receptor protein after a ligand binds to it?

Answer 7

The domain of the receptor protein will change its shape

Question 8

What are secondary messengers?

Answer 8

Secondary messengers are molecules that relay the signal that is received when the ligand first binds to the receptor. In addition to relaying the signal they can also amplify the signal and are essential for the signal transduction pathway.

Question 9

What can happen if a ligand binds to a ligand gated channel?

Answer 9

The channel can either open or close due to the conformational change of the channel as the ligand binds.