Write brief note on the following :
a) Synaptonemal complex
b) Metaphase plate

Explanation

Synaptonemal complex : The homologous chromosomes approach each other and from pairs called Bivalents and the process is called synapsis. The synapsis occurs at the both ends and progresses towards their centromeres called proterminal or the synapsis starts from their centromeres and the pairing progresses towards the end of the chromosomes called procentric or the pairing occurs at various points of homologous chromosomes called Randon synapsis. The paired homologous chromosomes are joined by a thick protein containing frame work caleed synaptonemal complex (Sc). Sc stabilizes the pairing of the homologous chromosomes and facilitates crossing over and recombination.
b) Metaphase plate : Metaphase chromaosomes is made up of two sister chromatids ehich were held together by the centromere. Small disc shaped structures at the surface of of tl centromeres that are moved into centre of the cell. Hence all chromosomes lies at the equator with one chromatid of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole. It is called .Metaphase Plate..