Your Friend Is Studying Mouse Fur Color and Has Isolated

question 38

Essay

Your friend is studying mouse fur color and has isolated the GPCR responsible for determining its color, as well as the extracellular signal that activates the receptor.She finds that, on addition of the signal to pigment cells (cells that produce the pigment determining fur color), cAMP levels rise in the cell.She starts a biotech company, and the company isolates more components of the signaling pathway responsible for fur color.Using transgenic mouse technology, the company genetically engineers mice that are defective in various proteins involved in determining fur color.The company obtains the following results.
• Normal mice have beige (very light brown) fur color.
• Mice lacking the extracellular signal have white fur.
• Mice lacking the GPCR have white fur.
• Mice lacking cAMP phosphodiesterase have dark brown fur.
Your friend has also made mice that are defective in the α subunit of the G protein in this signaling pathway.The defective α subunit works normally except that, once it binds GTP, it cannot hydrolyze GTP to GDP.What color do you predict that the fur of these mice will be? Why?

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Definitions:

Central Limit Theorem

A statistical theory that states that, given a sufficiently large sample size, the distribution of the sample mean will be approximately normally distributed, regardless of the distribution of the parent population.

Sample Mean

The sample mean is the average value of a sample set, calculated by adding together all of the observations and dividing by the number of observations.

Skewed to the Right

Describes a distribution of data that has a tail extending to the right, indicating that the majority of data points are on the left.

Sample Mean

The arithmetic average of a set of sample observations, used as an estimate of the population mean.