"Headless" Kinesin Mutants Only Contain the Stalk (Middle) and Tail

question 72

Multiple Choice

"Headless" kinesin mutants only contain the stalk (middle) and tail domains and can therefore dimerize with their wild-type kinesin partners. However, since they lack the motor (head) domain, the resulting dimers are unable to carry out processive transport of their cargoes and the mutation thus behaves as "dominant negative," meaning that the mutant not only is nonfunctional, but can also interfere with the function of its wild-type counterparts. If a headless mutant of a kinesin heavy chain involved in melanosome movement is overexpressed in fish melanocytes, what would you predict happens in these cells?

• A) Pigment dispersion would be inhibited and there would be more tug-of-war between the motors.
• B) Pigment aggregation would be inhibited and there would be more tug-of-war between the motors.
• C) Pigment dispersion would be inhibited and there would be less tug-of-war between the motors.
• D) Pigment aggregation would be inhibited and there would be less tug-of-war between the motors.

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Definitions:

Standard Deviation

A statistical measure of the dispersion or variability within a data set, indicating how spread out the values are.

Percentile

A statistical value that indicates the relative standing of a data point within a dataset, often used to compare individual scores to a broader population.

Mean

The arithmetic average of a set of numbers, calculated by adding all the numbers together and then dividing by the count of those numbers.

Reliable

The quality of being consistently good in quality or performance; trustworthy.