Substages of prophase

Hello! During prophase, do we know what happens fist, do chromosomes condense & then nuclear envelope disappears or the other way around? or do they happen simultaneously?
thank you

I think there is a step-by-step process but as all this happens fast enough we just learn it by they all occur simultaneously. you don’t have to know in detail this much for imat so don’t worry. :slight_smile:

Then how would you answer this question? from Imat 2015. the correct answer is E (row 3) i understand why row 3 is correct, im not sure thought how to disqualify option C (row 1)

You can cancel first row by checking only the ‘chromosomes line up at the equator’. This is definitely metaphase which happens before. Not last step before cytokinesis for sure
You have to know the steps for mitosis and meiosis for sure. You dont have to know the too in details. Such as if in metaphase what happens in which time interval. Knowing what spindle fibers are, and how metaphase plate occurs is enough

Form what i know, nuclear envelope disappearance occur just before DNA condensation, it is crucial because the breakdown of nuclear membrane let DNA interact with other cellular structures: especially spindle fibers. So, row 1 seem correct, however, the question said sequence of events which I think they want u to choose a pair of two consecutive events, i.e, in row 1 the first two events is consecutive but the following are quite far away from each other.
For row 2, the order is wrong.
Row 4, the order is wrong too.
Row 5, both the order and the events are not consecutive.

Lastly, row 3 meets with all those criteria. Friendly reminder, the options only give us one row to choose as a correct answer, so u better choose the perfect one. If they give the option row 1 and 3 then, u can choose that!!

Actually no, nuclear envelop becomes fragmented in prometaphase while the chromatin fibers coil at the beginning of mitosis, at prophase. Hence, Row 1 is disqualified.

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You can refer to Page 288 of Pearson Biology book as recommended by the study planner for a substage breakdown.