All Flashcards
What is the effect of crossing over during prophase I?
Increases genetic diversity by creating new combinations of alleles on the same chromosome.
What is the effect of independent assortment during metaphase I and II?
Increases genetic diversity by creating different combinations of maternal and paternal chromosomes in gametes.
What is the effect of random fertilization?
Increases genetic diversity by allowing any sperm to fertilize any egg, creating a unique combination of genes.
What is the effect of nondisjunction during meiosis?
Results in gametes with an abnormal number of chromosomes, potentially leading to genetic disorders such as Down syndrome.
What are the key steps of Crossing Over?
- Homologous chromosomes pair up. 2. Exchange of genetic material occurs during prophase I. 3. New combinations of alleles are created on the same chromosome.
What are the key steps of Independent Assortment?
- Homologous chromosome pairs align randomly at the metaphase plate during metaphase I and II. 2. Maternal and paternal chromosomes are distributed randomly into daughter cells. 3. Different combinations of chromosomes result in the gametes.
What are the steps that lead to Down Syndrome?
- Nondisjunction occurs during meiosis, resulting in an egg or sperm with an extra copy of chromosome 21. 2. The gamete with the extra chromosome 21 fertilizes a normal gamete. 3. The resulting zygote has three copies of chromosome 21 (trisomy 21), leading to Down syndrome.
What is the definition of Meiosis?
Cell division that produces four genetically unique haploid daughter cells from one diploid cell; reduces chromosome number by half.
What is the definition of Crossing Over?
Exchange of genetic material between homologous chromosomes during prophase I of meiosis.
What is the definition of Independent Assortment?
Random alignment and separation of homologous chromosomes during metaphase I and II of meiosis, leading to different combinations of chromosomes in gametes.
What is the definition of Random Fertilization?
The random union of any sperm with any egg during fertilization, increasing genetic variation.
What is the definition of Nondisjunction?
Failure of chromosomes to separate correctly during meiosis, resulting in gametes with an abnormal number of chromosomes.
What is the definition of Trisomy?
Having an extra copy of a chromosome (n+1).
What is the definition of Monosomy?
Missing a copy of a chromosome (n-1).