Question

Which among the following are cytogenetic events which occur during prophase I?
A. Synapsis
B. Crossing over
C. Chiasma formation
D. All of the above

Answer 1

Hint: A parent cell splits into two or more daughter cells in the process of cell division. Normally, cell division happens as part of a broader cell cycle. In eukaryotes, there are two forms of cell division: vegetative cell division (mitosis), in which each daughter cell is genetically identical to the parent cell, and reproductive cell division (haploid gametes), in which the number of chromosomes in the daughter cells is decreased by half (meiosis).

Complete answer:
Meiosis is a form of cell division that occurs in sexually reproducing animals' germ cells and is utilized to create gametes such as sperm and egg cells. It takes two rounds of division to produce four cells, each with only one copy of each chromosome (haploid). Additionally, genetic material from the paternal and maternal copies of each chromosome is crossed over before division, resulting in novel code combinations on each chromosome.
A single cell divides twice to produce four haploid daughter cells during meiosis. The gametes — sperm in men and eggs in females – are these cells. The meiosis process is split into two phases. Each step is further split into stages.
Meiosis I:
Prophase I
Metaphase I
Anaphase I
Telophase I
Cytokinesis I
Meiosis II:
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis II

Thus, Meiosis is divided into two stages: meiosis I and meiosis II. Prophase I, metaphase I, anaphase I, and telophase I are the phases of meiosis I. During meiosis I, cells cross across. Synapsis occurs when homologous chromosomes couple during meiosis I. The synapsis occurs between homologous chromosomes, allowing them to cross across more easily. During prophase, I, the development of cross-shaped structures, also known as chiasma formation, reveals the precise moment of crossing over.

As a result, option D: All of the above is the right answer.

Note:
Binary fission is a type of vegetative cell division in which the genetic material of prokaryotes (bacteria and archaea) is divided evenly into two daughter cells. While binary fission is the most common method of prokaryote division, other methods of division, such as budding, have been reported. A single cycle of DNA replication precedes all cell divisions, independent of organism.