Question

What would have been an appropriate conclusion if Gorbsky et al had seen the photobleached mark to move towards the centrosome? Select one: a. None of the statements could be concluded from that result b. Dyenin moves the chromosomes towards the poles of the spindle c. Microtubules shorten at the chromosome end during anaphase d. Microtubules shorten at the centrosome end during anaphase e. Kinesin moves the chromosomes towards the poles of the spindle

Answer 1

The correct answer is option c - Microtubules shorten at chromosome end during anaphase

Explanation: Gorbsky et al , by photobleaching had demonstrated that the marked domain did not move with respect to the pole which is situated nearby. Kinetochore microtubules became shortened as a result of subunit loss at the kinetochore.

The correct answer is option e- Two bands one formed using only N14 and one formed by N15.

Explanation: The Conservative model of DNA replication states that two parental strands of DNA double helix direct the synthesis of entirely new DNA double helix. The two old strands of DNA remain associated with each other and two newly developed strand remain associated together. New and old strand of DNA never form hybrid DNA double helix. This strategy will be repeated in the following cycles. So there will be two bands after three cycles of replication. One narrow band at the lower position (consist of two strands which have N¹⁵) and one thick band at the upper position (containing only N¹⁴).