Which of the Following Is (Are)not Characteristics of the Pathways

question 70

Multiple Choice

Which of the following is (are) not characteristics of the pathways activated by second messengers?

• A)Each signaling pathway consists of a series of distinct proteins that operate in sequence.
• B)Each protein in the pathway typically acts by altering the conformation of the previous (upstream)protein in the series,an event that activates or inhibits the protein.
• C)Alterations in the conformations of signaling proteins are often accomplished by protein kinases and protein phosphatases that,respectively,add or remove phosphate groups from other proteins.
• D)Some phosphatases and protein kinases in the pathway have numerous proteins as their substrates; others act on only a single protein substrate or a single amino acid of a protein substrate.
• E)Many of the protein substrates of the pathway enzymes are enzymes themselves,like other kinases and phosphatases,but they include ion channels,transcription factors and various regulatory molecules.

---

Definitions:

Heart Attack

A medical emergency characterized by the death of heart muscle due to the loss of blood supply, commonly caused by a blockage in one or more of the coronary arteries.

Estrogen

A group of sex hormones that play an essential role in the reproductive system of females and the development of female secondary sexual characteristics.

Radiation

The emission or transmission of energy in the form of waves or particles through space or through a material medium.

Chemotherapy

A type of cancer treatment that uses one or more anti-cancer drugs as part of a standardized chemotherapy regimen to kill or slow the growth of cancer cells.