Genetic Variation During Meiosis exam Flashcards
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Terms in this set (25)
Crossing Over
The process during prophase 1 of meiosis 1 where homologous chromosomes exchange genetic material, forming non-identical sister chromatids.
What is independent assortment?
The random alignment of homologous chromosome pairs during metaphase 1 of meiosis 1, creating numerous genetic combinations.
Nondisjunction
An error during meiosis where chromosomes fail to separate properly, leading to aneuploid cells.
What is the result of nondisjunction?
It can lead to aneuploidy, resulting in conditions like Down syndrome or cell death.
Synapsis
The process where homologous chromosomes align their DNA sequences at similar alleles to prompt crossing over.
What is the chiasma?
The site of crossing over where homologous chromosomes exchange genetic material.
Aneuploidy
A condition where cells have an abnormal number of chromosomes, either too many or too few.
What is the formula for independent assortment combinations?
2n, where n is the haploid number of chromosomes.
Prophase 1
The stage of meiosis 1 where crossing over occurs.
What happens during metaphase 1 of meiosis 1?
Homologous chromosomes align randomly in two rows on the metaphase plate, leading to independent assortment.
Trisomy 21
A genetic disorder caused by having three copies of chromosome 21, also known as Down syndrome.
What is the significance of crossing over?
It creates genetic diversity by forming non-identical sister chromatids.
Metaphase 1
The stage of meiosis 1 where independent assortment occurs.
What is the outcome of meiosis?
Four haploid cells that are genetically different from one another.
Chiasma
The attachment site between two homologous chromosomes where crossing over occurs.
What is synapsis?
The alignment of homologous chromosomes to facilitate crossing over.
Genetic Diversity
The variety of genetic combinations that result from processes like crossing over and independent assortment during meiosis.
What is the role of independent assortment in genetic diversity?
It increases the number of possible genetic combinations by allowing homologous chromosomes to align randomly.
What is the difference between mitosis and meiosis in terms of genetic diversity?
Mitosis creates genetically identical cells, while meiosis creates genetically diverse cells.
Down Syndrome
A genetic disorder caused by an extra copy of chromosome 21, resulting from nondisjunction.
What is the significance of the chiasma?
It is the physical site where crossing over and genetic material exchange occur between homologous chromosomes.
Genetic Variation
The differences in DNA sequences among individuals, generated during meiosis.
What is the role of meiosis in sexual reproduction?
It produces haploid gametes that combine during fertilization to form a genetically unique offspring.
Independent Assortment
The random distribution of homologous chromosomes during metaphase 1 of meiosis 1.
What is the outcome of crossing over?
Non-identical sister chromatids, contributing to genetic diversity.