Question

Chiasmata is (i)___________ and it is formed during the (ii)___________ stage of meiosis.

• A. (i) - the X-shaped structure formed when the synaptonemal complex dissolves and the homologous chromosomes remain attached at site of crossover
  (ii) - zygotene
  
• B. (i) - the structure formed by the pairing of homologous chromosomes during synapsis
  (ii) - zygotene
  
• C. (i) - the structure formed by the pairing of homologous chromosomes during synapsis
  (ii) - diplotene
  
• D. (i) - the X-shaped structure formed when the synaptonemal complex dissolves and the homologous chromosomes remain attached at site of crossover
  (ii) - diplotene
  

Answer 1

The correct option is D (i) - the X-shaped structure formed when the synaptonemal complex dissolves and the homologous chromosomes remain attached at site of crossover

(ii) - diplotene

Chiasmata is the X-shaped structure which is seen in the diplotene phase of prophase I of meiosis I. It is formed due to the dissolution of the synaptonemal complex and separation of the homologous chromosomes at sites except at the sites of crossover.

The structure formed by the pairing of homologous chromosomes during synapsis is known as the bivalent and it is seen during the zygotene stage of prophase I of meiosis I. This pairing continues upto the pachytene stage.