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Multiple Choice
Which process during meiosis is primarily responsible for increasing genetic variation in gametes?
A
Formation of the mitotic spindle
B
Separation of sister chromatids during anaphase II
C
Crossing over between homologous chromosomes during prophase I
D
Replication of DNA during interphase
Verified step by step guidance
1
Understand the purpose of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half and produces gametes (sperm and egg cells). It is essential for sexual reproduction and introduces genetic variation.
Identify the key stages of meiosis: Meiosis consists of two main divisions, meiosis I and meiosis II. Meiosis I is where homologous chromosomes pair up and exchange genetic material, while meiosis II separates sister chromatids.
Focus on prophase I: During prophase I of meiosis I, homologous chromosomes pair up in a process called synapsis. This pairing forms structures called tetrads, which are crucial for genetic recombination.
Explain crossing over: Crossing over occurs during prophase I when homologous chromosomes exchange segments of DNA at points called chiasmata. This process creates new combinations of alleles, increasing genetic variation in the resulting gametes.
Clarify why other options are incorrect: Formation of the mitotic spindle and separation of sister chromatids during anaphase II are important for cell division but do not directly increase genetic variation. DNA replication during interphase is necessary for meiosis but does not contribute to genetic diversity.