Question

During which stages (or prophase I substages) of meiosis do you expect to find the bivalents and DNA replication respectively?

• A. pachytene and interphase (between two meiotic divisions)
• B. pachytene and interphase Gust prior to prophase I)
• C. pachytene and S phase (of interphase just prior to prophase I)
• D. zygotene and S phase (of interphase prior to prophase I).

Answer 1

Answer: (B)

: During meiosis the zygotene stage is marked by pairing of homologous chromosomes known as synapsis. Each pair is called a bivalent. During pachytene the pairing of chromosomes reaches completion. S-phase (phase of DNA synthesis) follows G, phase. DNA and histones are synthesized in this phase and each chromosome divides into two chromatids. The time taken for this phase is 30-50% of the total mitotic cycle.