To examine: Whether the statement “all second messengers are water-soluble and diffuse freely through the cytosol” is true or false.
Introduction:
Second messengers are small intracellular signaling molecules which are released in response to extracellular signals known as first messengers. They are of three types- hydrophobic, hydrophilic, and gaseous.
Answer to Problem 1P
Correct answer: The statement is false.
Explanation of Solution
Second messengers are classified into three types: hydrophobic, hydrophilic, and gaseous. Hydrophobic molecules are water insoluble (fat soluble) and diffuse from the plasma membrane, for example, diacyl glycerol. Hydrophilic molecules such as cyclic AMP are water soluble and diffuse in the cytosol. Gaseous molecules such as carbon monoxide can diffuse through both plasma membrane and cytosol. Thus, all second messengers are not water-soluble.
Hence, the statement is false.
Want to see more full solutions like this?
Chapter 15 Solutions
Molecular Biology of the Cell (Sixth Edition)