AP BIOLOGY

LABORATORY REVIEW

MITOSIS AND MEIOSIS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following best describes how the process of crossing over during meiosis leads to an increase in genetic diversity?
A
During prophase I, DNA replication takes place, and homologous chromosomes trade places with each other before lining up in preparation for metaphase.
B
During prophase I, DNA segments are exchanged between homologous chromosomes, resulting in different combinations of alleles.
C
During prophase II, fragments of DNA break off of chromosomes and attach to the ends of other chromosomes, resulting in different gene sequences.
D
During prophase II, sister chromatids separate from each other, and as they travel to opposite ends of the cell, DNA segments of nearby chromosomes are exchanged.
Explanation: 

Detailed explanation-1: -So, the correct answer is ‘Crossing over produces new combinations of genes on alleles, increasing genetic variation.

Detailed explanation-2: -During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.

Detailed explanation-3: -Which statement best describes the process of crossing-over? It takes place between homologous chromosomes and results in new gene combinations.

Detailed explanation-4: -Correct answer: Crossing over is a process that happens between homologous chromosomes in order to increase genetic diversity. During crossing over, part of one chromosome is exchanged with another. The result is a hybrid chromosome with a unique pattern of genetic material.

Detailed explanation-5: -Crossing over is an enzyme-mediated process, where the exchange of genetic material between non-sister chromatids of homologous chromosomes takes place. It occurs at the pachytene stage of prophase I of meiosis.

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