Question

The exchange of genetic material between chromatids of paired homologous chromosomes during first meiotic division is called

• A. transformation
• B. chiasmata
• C. crossing over
• D. synapsis

Answer 1

The Correct Option is C

The process described in the question pertains to a specific event during meiosis, which is a type of cell division that reduces the chromosome number by half and leads to the production of gametes or spores.

The correct answer to the question is crossing over. Let's understand the reasoning and eliminate the other options:

1. Crossing Over: This is the accurate term for the exchange of genetic material between non-sister chromatids of homologous chromosomes. It occurs during prophase I of meiosis. It allows for genetic diversity in the resulting gametes by creating new combinations of alleles.
2. Transformation: This refers to a process in bacteria where they can uptake external genetic material from their environment. This is completely unrelated to the process described in the question.
3. Chiasmata: This term describes the visible points of crossing over between chromatids, but it is not the process itself. Chiasmata are the physical manifestations of crossing over and are seen during the later stages of prophase I.
4. Synapsis: This is the pairing of homologous chromosomes during prophase I of meiosis. While synapsis is necessary for crossing over to occur, it is not the exchange of genetic material itself.

Thus, the exchange of genetic material between chromatids of paired homologous chromosomes is most accurately described by the term crossing over.