You Are Interested in Cell-Size Regulation and Discover That Signaling

question 16

Multiple Choice

You are interested in cell-size regulation and discover that signaling through a GPCR called ERC1 is important in controlling cell size in embryonic rat cells.The G protein downstream of ERC1 activates adenylyl cyclase, which ultimately leads to the activation of PKA.You discover that cells that lack ERC1 are 15% smaller than normal cells, while cells that express a mutant, constitutively activated version of PKA are 15% larger than normal cells.Given these results, which of the following treatments to embryonic rat cells should lead to smaller cells?

• A)addition of a drug that causes cyclic AMP phosphodiesterase to be hyperactive
• B)addition of a drug that prevents GTP hydrolysis by Gα
• C)addition of a drug that activates adenylyl cyclase
• D)addition of a drug that mimics the ligand of ERC1

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Definitions:

Offspring

The product of reproduction of a new organism produced by one or more parents.

Genes

Units of heredity made up of DNA that influence characteristics and are passed from parents to offspring.

Blood Types

Classifications of human blood based on the presence or absence of antibodies and inherited antigenic substances on the surface of red blood cells.

Alleles

Alternative versions of a gene that produce distinguishable phenotypic effects, occupying the same position or locus on a chromosome.