Phosphorylation cascades are useful signal transduction pathways because they ________.

• A. Allow proteins to be easily activated by adding or removing a phosphate group.
• B. Allow proteins to be easily deactivated by adding or removing a phosphate group.
• C. Amplify the original signal many times.
• D. All of the above.

Answer: (D)

Verified step by step guidance

1. Understand the concept of phosphorylation cascades: These are sequences of events where one enzyme phosphorylates another, leading to a chain reaction that amplifies the cellular response to a signal.
2. Recognize that phosphorylation involves the addition of a phosphate group to a protein, which can activate or deactivate the protein's function. This is a reversible process, allowing for precise control of protein activity.
3. Consider how phosphorylation cascades amplify signals: Each step in the cascade can activate multiple molecules, leading to a large amplification of the original signal.
4. Evaluate the options given: Each option describes a characteristic of phosphorylation cascades. They allow for easy activation and deactivation of proteins and amplify the signal.
5. Conclude that all the provided options are correct, as they collectively describe the benefits and functions of phosphorylation cascades in signal transduction pathways.