This could be one of two types of signaling:
Paracrine signaling is where a signaling molecule produced from one cell affects other types of adjacent cells.
Autocrine signaling is where a signaling molecule produced from one cell affects itself and other adjacent cells of the same type.
I am not aware of any specific element "signaling" this. Towards the end of a stars life, however, relatively large amounts of heavier elements are produced.
Molecular Shape is crucial in a living system because it determines most biological molecules recognize and respond to one another. An example would be when signal molecules releases its signal, it releases a unique shape that specifically fits together with the shape of the receptor molecules on the surface of the receiving cell, much as a key fits into a lock.
Signal transduction
The sound causes vibration of special structures in our ear. These structures, called stereocilia, are basically sort of "cell hair". When these hair move, a signal in the cells is produced. This signal is transmitted by nerves to brain. The existence of this signal in brain = "activation of brain cells". How do our brain cells work when we talk? They just produce signals leading to nerves which control our vocal centers. The question is not specific enough.
Signal Transduction
yes it does affect the signal.
No.
AC sinewave
A specific indication to do something.
Proton density within the tissue will affect the signal intensity on an MRI. The thicker the tissue, the more intense the return signal will be upon detection.
If you are downloading something from the internet, it does not affect the strength of the Wi-Fi signal or other internet signal, since that is solely based on the router's performance or modem's performance, but the speed at which it operates is greatly affected.
hormones
Sudhir K. Sopory has written: 'Signal transduction in plants' -- subject(s): Plant cellular signal transduction, Plant molecular biology
analog signal
In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave (a continuous signal) to a sequence of samples (a discrete-time signal).
Yes.
It requires a signal device in order to pass through.