Question

Select the correct option.

A.Synapsis aligns homologous chromosomes	1. Anaphase II
B. Synthesis of RNA and protein	2. Zygotene
C. Action of enzyme recombinase	3. G2​ phase
D.Centromeres do not separate but chromatidsmove towards opposite pole	4. Anaphase I
	5. Pachytene

A. A-1, B-2, C-5, D-4
B. A-2, B-3, C-4, D-5
C. A-2, B-1, C-3, D-4
D. A-2, B-3, C-5, D-4

Answer 1

Hint: The tight pairing of the homologous (similar in position, structure) chromosomes is called synapsis. In synapsis, the genes on the chromatids of the homologous chromosomes are aligned with each other. So, there is an exchange of genetic material between the homologous chromosomes.

Step by step answer:A.Homologous chromosomes pair up by a process called as synapsis and form a complex bivalent structure in the zygotene stage of prophase I of meiosis I. Prophase 1 of Meiosis is the first stage of meiosis and is explained by five different phases, Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis
B. In the G2 phase the Synthesis of RNA and protein occurs. This particular phase is spent in the synthesis of molecules other than DNA, which are required for the cell division. The G2 phase is not a necessary part of the cell cycle, as some cell types (particularly young Xenopus embryos and some cancers) proceed directly from DNA replication to mitosis.
C. Enzyme recombinase is involved in crossing over that occurs during the pachytene stage of prophase I of meiosis I. Crossing over is a process or phenomenon in which the exchange of segments occurs between non-sister chromatids of homologous chromosomes.
D. In anaphase I stage of meiosis I, chromosomes move to opposite poles because centromeres do not separate. In anaphase I, the sister chromatids remain attached to their centromeres and move together toward the poles.
So, the correct answer is 'A-2, B-3, C-5, and D-4'

Note: The cell cycle is a continuous, repeating function of living cells in which they grow and divide. The first phase of the cell cycle is interphase, consisting of three stages: the gap phase 1, the synthesis phase, and gap phase 2. The second phase is mitosis, which has 4 stages: prophase, metaphase, anaphase, and telophase.