Which of the Following Statements Is True of Signal Molecules

question 12

Multiple Choice

Which of the following statements is true of signal molecules?

• A) When signal molecules first bind to receptor tyrosine kinases, the receptors phosphorylate a number of nearby molecules.
• B) In response to some G protein-mediated signals, a special type of lipid molecule associated with the plasma membrane is cleaved to form IP₃ and calcium.
• C) In most cases, signal molecules interact with the cell at the plasma membrane and then enter the cell and eventually the nucleus.
• D) Toxins such as those that cause botulism and cholera interfere with the ability of activated G proteins to hydrolyze GTP to GDP, resulting in phosphodiesterase activity in the absence of an appropriate signal molecule.
• E) Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled receptors.

---

Definitions:

Chicken Pox

A contagious viral disease characterized by an itchy rash and red spots or blisters all over the body.

Painful Blisters

Fluid-filled bumps on the skin that are often caused by friction, burns, or infections and can cause discomfort.

Herpes Simplex Virus

A virus causing contagious sores, most often around the mouth or on the genitals.

Sanitization

is the process of cleaning and disinfecting surfaces or objects to reduce the presence of harmful microorganisms to safe levels.