Final answer:
The proteins that make up the central element of the synaptonemal complex are known as zip proteins, which are essential for the proper alignment and recombination of homologous chromosomes during meiosis.
Step-by-step explanation:
The synaptonemal complex is a protein structure that plays a crucial role in the pairing of homologous chromosomes during prophase I of meiosis. The central element of the synaptonemal complex is held together by a group of proteins known as synaptonemal complex proteins, often referred to as zip proteins. These proteins are not to be confused with microtubules, actins, or cohesins, which have different roles in cell division. Microtubules are involved in forming the mitotic spindle but are not part of the synaptonemal complex; actins are part of the cell's cytoskeleton; and cohesins help in the cohesion of sister chromatids. During early prophase I, the synaptonemal complex binds homologous chromosomes tightly together in perfect alignment, a process that is critical for subsequent genetic recombination and proper segregation of chromosomes.
Therefore, the final answer is: 1) Zip proteins make the central element of the synaptonemal complex.
In two line explanation: Zip proteins are responsible for holding together the central element of the synaptonemal complex, which is essential for the proper alignment and recombination of homologous chromosomes during meiosis.