Which Observation Suggested to Sutherland the Involvement of a Second

question 21

Multiple Choice

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells?

• A) Enzymatic activity was proportional to the amount of calcium added to a cell-free extract.
• B) Receptor studies indicated that epinephrine was a ligand.
• C) Glycogen breakdown was observed only when epinephrine was administered to intact cells.
• D) Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined.
• E) Epinephrine was known to have different effects on different types of cells.

---

Definitions:

Mitosis

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Meiosis I

The first division in meiosis, a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, important for sexual reproduction.

Meiosis II

The second division in meiosis, where the two cells produced in Meiosis I divide again without DNA replication, resulting in four haploid cells.

Meiotic Divisions

Meiotic divisions are the process of cell division in sexually reproducing organisms that reduces the chromosome number by half, resulting in the production of haploid reproductive cells.