Question

During gamete formation, the enzyme recombinase plays an active role during
A. Prophase I
B. Prophase II
C. Metaphase I
D. Anaphase II

Answer 1

Hint: Gamete formation occurs by the process of meiosis. Meiosis is also alternatively known as reduction division. In this process, the germ cell (egg/ ovum or the sperm cells) undergoes two dividing phases which result in the production of four gametes.

Complete answer:
Meiosis is the process that occurs in two stages of meiosis 1 and meiosis 2 crossing over and reduction in chromosome numbers occur during the meiosis 1 stage. Each meiosis stage will be completed after 4 phases like prophase, metaphase, anaphase, telophase chronologically.
The meiosis 1; prophase 1 stage is the very detailed and complicated stage, comprising leptotene, zygotene, pachytene, diplotene, and diakinesis. The crossing over between non-sister chromatids of the same bivalent form occurs during the pachytene stage. This is the complex enzyme-catalyzed action; the enzyme used is the recombinase enzyme. The recombinase enzyme complex carries out the crossing over in the pachytene substage of prophase 1 of meiosis 1 reduction division.
In stages like prophase II, sister chromatids are condensed and a new set of spindle fibers begins to form & nuclear envelopes start fragmenting.
During metaphase I the homologous chromosomes line up at the equator randomly.
During anaphase II, the sister chromatids are pulled apart from each other because of the shortening of the kinetochore’s microtubules, followed by the telophase II stage resulting in the formation of new granddaughter cells.

Therefore, the correct answer is option A. Prophase I.

Note:
During gamete formation, the enzyme recombinase participates and plays an active role in the prophase I stage of meiosis, when crossing over between the non-sister chromatids occurs. Crossing over is an enzyme-mediated process and the enzyme involved is the recombinase enzyme.