Question

chapter 10 pre-test question 8
1 part | -- of 1 point
what is crossing over?
a direct consequence of the separation of sister chromatids
making an rna copy of a dna strand
also referred to as the \independent assortment of chromosomes\
the movement of genetic material from one chromosome to a nonhomologous chromosome
the exchange of homologous portions of nonsister chromatids

Explanation:

Crossing - over occurs during meiosis. It is the exchange of genetic material between homologous chromosomes. Homologous chromosomes pair up (synapsis) and form chiasmata. At these chiasmata, segments of non - sister chromatids (which are homologous portions) are exchanged.

• The separation of sister chromatids is part of mitosis or meiosis II and not directly related to crossing - over.
• Making an RNA copy of a DNA strand is transcription, not crossing - over.
• Independent assortment of chromosomes is about the random alignment of homologous chromosome pairs during metaphase I, different from crossing - over.
• Movement of genetic material to a non - homologous chromosome is a type of chromosomal translocation, not crossing - over.

Answer:

the exchange of homologous portions of nonsister chromatids