PATHOLOGY

PATHOLOGY MCQ

CELL DAMAGE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which events occur in prometaphase? (select 3)
A
Microtubules build up from centrosomes
B
The nucleus breaks down
C
Centrosomes move to opposite poles
D
Microtubules attach to chromosomes
E
Chromosomes line up in the center of the cell
Explanation: 

Detailed explanation-1: -In prometaphase, kinetochores appear at the centromeres and mitotic spindle microtubules attach to kinetochores. In metaphase, chromosomes are lined up and each sister chromatid is attached to a spindle fiber. In anaphase, sister chromatids (now called chromosomes) are pulled toward opposite poles.

Detailed explanation-2: -During ‘prometaphase’, chromosomes oscillate back and forth between centrosomes and the center of the cell while microtubules attach to the kinetochore areas of chromosomes facing the opposite mitotic poles, therefore ensuring equal separation and subsequent distribution to the dividing daughter cells.

Detailed explanation-3: -During prometaphase the microtubules of the mitotic spindle attach to the kinetochores of condensed chromosomes. The kinetochores of sister chromatids are oriented on opposite sides of the chromosome, so they attach to microtubules emanating from opposite poles of the spindle.

Detailed explanation-4: -When prophase is complete, the cell enters prometaphase-the second stage of mitosis. During prometaphase, phosphorylation of nuclear lamins by M-CDK causes the nuclear membrane to break down into numerous small vesicles. As a result, the spindle microtubules now have direct access to the genetic material of the cell.

Detailed explanation-5: -The spindle microtubules are attached to condensed chromosomes at metaphase.

There is 1 question to complete.