Question

multiple choice 1 point
paired homologous chromosomes
the process depicted in the image above is best summarized by which of the following descriptions?
during the synthesis phase of the cell cycle, dna molecules replicate to generate identical daughter cells.
centromeres align specific gene sequences of homologous chromosomes during mitotic divisions.
the spindle apparatus attaches at chiasma during metaphase of mitosis.
during meiosis, crossing over leads to recombination of alleles between homologous chromosomes.

Explanation:

The image shows paired homologous chromosomes with chiasma, indicating crossing over. Crossing over occurs during meiosis, leading to allele recombination between homologous chromosomes. Let's analyze other options:

• Option 1: DNA replication (synthesis phase) involves copying DNA, not chromosome pairing/crossing over.
• Option 2: Centromere alignment of homologous chromosomes during mitosis is incorrect (mitosis has sister chromatids, meiosis has homologous pairs aligning in metaphase I, but the image shows crossing over, not centromere alignment for mitosis).
• Option 3: Spindle attaches at chiasma during mitosis is wrong (spindle attaches at kinetochores, and chiasma is a meiosis - specific structure).
• Option 4: During meiosis, crossing over at chiasma (visible in the image) leads to allele recombination between homologous chromosomes, which matches the depicted process.

Answer:

During meiosis, crossing over leads to recombination of alleles between homologous chromosomes.