Question

1. What are two outcomes that may happen as a result of signal transduction? - one is fast other is slow

2. Why is it better for cells to have pathways that have a small amount of “steps” and pathways that have a greater number of “steps” in their pathways? -think RTK/Ras/MapK versus JAK/STAT

Answer 1

Answer :

1)

The two outcomes of signal transduction are inhibitory or facilitatory.

In comparison of speed. First type is fast, which requires only action of protein, as in muscle contraction.

Second type is slow where it requires synthesis of new protein.

2)

Advantages of having few steps in signal transduction.

3 basic steps of signal transduction are

1. Reception

2. Transduction

3. Response

The pathways with bare minimum steps will be having maximum efficiency.

RTK/Ras/MapK pathway has to undergo several steps of phosphorylation and many intermittent mediators.

Where as JAK/STAT pathway has got only 3 steps in signal transduction.

So the pathways with minimum steps will be faster and less chance of inhibition.

Also they can easily interconnect with other pathways such as p13K/akT/mTor.

Coming to advantages of pathways with more number of steps

a. Amplification of response to signals.

b. Specificity of response.