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

(N/A) Synaptonemal complex: During the prophase-$I$ of meiosis,a zipper-like proteinaceous structure forms between homologous chromosomes. This is called the synaptonemal complex. It facilitates the pairing (synapsis) of homologous chromosomes and is essential for the process of crossing over,which involves the exchange of genetic material between non-sister chromatids.
$(b)$ Metaphase plate: During metaphase,the chromosomes align themselves at the equatorial plane of the cell. This imaginary plane of alignment is known as the metaphase plate. The centromeres of the chromosomes are positioned on this plate,and the spindle fibers from opposite poles of the cell attach to the kinetochores of the chromosomes to facilitate their future separation.