The accompanying figure shows data from an experiment in which researchers measured how far dynein (a motor protein) traveled in the presence and absence of dynactin (another type of protein). The y-axis shows the percent of the time that the researchers observed either dynein or dynein + dynactin "walking" a certain distance on a microtubule. What can you conclude from these data?
A) The addition of dynactin caused dynein to travel farther along the microtubule.
B) Dynein traveled farther in the absence of dynactin.
C) A higher fraction of the dynein proteins were motile in the absence of dynactin.
D) Dynactin would have the same effects on dynein movement on microfilaments.

Question

The accompanying figure shows data from an experiment in which researchers measured how far dynein (a motor protein) traveled in the presence and absence of dynactin (another type of protein). The y-axis shows the percent of the time that the researchers observed either dynein or dynein + dynactin "walking" a certain distance on a microtubule. What can you conclude from these data? 
A) The addition of dynactin caused dynein to travel farther along the microtubule. 
B) Dynein traveled farther in the absence of dynactin. 
C) A higher fraction of the dynein proteins were motile in the absence of dynactin. 
D) Dynactin would have the same effects on dynein movement on microfilaments.

Quizplus · Accepted Answer

The figure shows that the presence of dynactin led to a higher percentage of dynein + dynactin traveling farther distances on the microtubule. Therefore, the addition of dynactin caused dynein to travel farther along the microtubule. Option B is incorrect because the figure does not show that dynein traveled farther in the absence of dynactin. Option C is incorrect because the data does not provide information on the fraction of motile dynein proteins in the absence of dynactin. Option D is incorrect because microfilaments were not used in the experiment and their effect on dynein movement was not measured.

The Accompanying Figure Shows Data from an Experiment in Which