Define and discuss these terms: (a) synapsis, (b) bivalents, (c) chiasmata, (d) crossing over, (e) chromomeres, (f) sister chromatids, (g) tetrads, (h) dyads, (i) monads.

Key Concepts

Synapsis

Synapsis is the process during meiosis where homologous chromosomes pair up closely along their lengths. This pairing is crucial for the exchange of genetic material and occurs during prophase I of meiosis. The close alignment allows for the formation of structures called bivalents, which facilitate genetic recombination.

Chiasmata

Chiasmata are the points where homologous chromosomes exchange genetic material during meiosis. They form as a result of crossing over, where segments of DNA are swapped between non-sister chromatids. This process increases genetic diversity in gametes and is visually represented in the image, highlighting the areas where chromosomes are intertwined.

Crossing Over

Crossing over is a genetic recombination process that occurs during prophase I of meiosis, where segments of DNA are exchanged between homologous chromosomes. This exchange results in new combinations of alleles, contributing to genetic variation in offspring. It is a key mechanism for evolution and adaptation in populations.