Figure 7 shows the mean distance between centromeres and the poles (ends) of the spindle during mitosis - AQA - A-Level Biology - Question 6 - 2021 - Paper 1

To find the rate of movement, we first need to determine the distance moved by the centromeres during phase E, which can be determined from the graph provided in Figure 7. From visual observation, the mean distance between centromeres and poles at phase E (at approximately 2000 seconds) is about 15 µm, while at the previous phase (D), it is around 18 µm.

The distance moved can be calculated as follows:

$ext{Distance moved} = ext{distance in D} - ext{distance in E} = 18 ext{ µm} - 15 ext{ µm} = 3 ext{ µm}$

Next, we calculate the time taken between phases D and E, which is about 500 seconds.

The rate of movement in µm minute$^{-1}$ is calculated using the formula:

ext{Rate} = rac{ ext{Distance moved}}{ ext{Time taken}} = rac{3 ext{ µm}}{500 ext{ s}}

To convert seconds to minutes, we multiply by 60:

ext{Rate} = rac{3}{500} imes 60 = 0.36 ext{ µm minute}^{-1}

Thus, the final answer for the rate of movement of the centromeres during phase E is:

$0.360 ext{ µm minute}^{-1}$