How does a protein kinase cascade work? what does it do to the original signal?

A protein kinase is an enzyme which catalysis the phosphorylation reaction.

The phosphorylation can either activate or deactivate other proteins or receptors.

A protein kinase cascade refers to the series of events in which a chain reaction of phosphorylation takes place by which thousands of proteins are phosphorylated.

It helps in signal transduction through which signals (usually hormone) from outside the cell are amplified and transferred to the target molecule present inside the cell.

For example, tyrosine kinase cascade.

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.