Question

The shape of chiasmata is
A. C-Shaped
B. X-Shaped
C. Y-Shaped
D. U-Shaped

Answer 1

Hint: The chiasma is a structure that forms between a couple of homologous chromosomes by crossover recombination and physically connects the homologous chromosomes throughout meiosis. The paired chromosomes begin to segregate into two pairs of chromatids. The synapsis ends with the disintegration of the synaptonemal complex. The homologous pairs of chromosomes continue to be attached at Chiasma. The chromosomes start with the coil, which makes the Chiasma very obvious under the microscope.

Complete step-by-step answer:
Chiasmata is the point at which two homologous non-sister chromatids interchange genetic substances during crossing over. Chiasmata is the X-shaped structure developed because of the point of contact between combined chromatids during meiosis. It is the point that represents the crossover in which the homologous chromosomes are interconnected. At chiasmata crossing over takes place in the pachytene phase. The genetic constitution of the daughter cells is different from the parent cells because of crossing over. There is a combination of the maternal and paternal genes in each chromosome of daughter cells mostly.
The number of chiasmata differs depending on the species and the length of the chromosome. There must be at least one chiasma per chromosome for the correct separation of homologous chromosomes during meiosis I, but as much as 25.
Therefore, the correct option is B.

Note: In several species, chiasmata are developed after the recognition of homologous chromosomes (pairing), the close association of combined chromosomes by the synaptonemal complex (SC), and the reciprocal interchange of series by the homologous recombination (HR) process.