AP BIOLOGY

CELL DIVISION

MEIOSIS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Chromosomes of a homologous pair separate from each other during:
A
Anaphase I
B
Anaphase II
C
Metaphase I
D
Prophase II
Explanation: 

Detailed explanation-1: -During anaphase I stage of meiosis, the cell starts to lengthen. The two homologs of each chromosome pair separate and move toward opposite poles, drawn by the microtubules of the spindle apparatus. This contrasts with mitosis, where the sister chromatids of each homolog separate and move toward opposite poles.

Detailed explanation-2: -Anaphase I: In anaphase I, the attachment of the spindle fibers is complete. The homologous chromosomes are pulled apart and move towards opposite ends of the cell. Do not confuse this with the pulling apart of sister chromatids! This is the point in which reduction occurs with 23 chromosomes moving to each pole.

Detailed explanation-3: -Figure 3: During anaphase I, the homologous chromosomes are pulled toward opposite poles of the cell. During anaphase I, the microtubules disassemble and contract; this, in turn, separates the homologous chromosomes such that the two chromosomes in each pair are pulled toward opposite ends of the cell (Figure 3).

Detailed explanation-4: -The chromosomes are separated by a structure called the mitotic spindle. The mitotic spindle is made of many long proteins called microtubules, which are attached to a chromosome at one end and to the pole of a cell at the other end. The sister chromatids are separated simultaneously at their centromeres.

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