Meiosis and Genetic Diversity - AP Biology
- What is the result of meiosis in terms of ploidy?
- Reduction from diploid to haploid. Chromosome number decreases by half during meiosis.
- What is a homologous chromosome?
- Chromosomes with the same genes but possibly different alleles. Chromosome pairs with same gene loci but different alleles.
- What is the significance of meiosis in evolution?
- Increases genetic variation, driving evolution. Genetic variation enables natural selection and adaptation.
- What is genetic recombination?
- The process of forming new allelic combinations in offspring. Results from crossing over and independent assortment.
- What is the significance of meiosis II?
- Separates sister chromatids to form four unique haploid cells. Similar to mitosis but produces genetically diverse gametes.
- Which phase of meiosis does not involve DNA replication?
- Meiosis II. DNA replication occurred before meiosis I began.
- Define haploid.
- A cell with one complete set of chromosomes. Gametic chromosome number; half of diploid.
- Which phase is characterized by the separation of sister chromatids?
- Anaphase II. Final step in creating genetically unique haploid gametes.
- What is the outcome if nondisjunction occurs in meiosis?
- Aneuploidy, such as trisomy or monosomy. Abnormal chromosome numbers cause developmental problems.
- Identify the phase where nuclear envelopes reform around haploid sets.
- Telophase I. Brief interphase may occur before meiosis II begins.
- What occurs during anaphase I of meiosis?
- Homologous chromosomes are separated to opposite poles. Reduces chromosome number from diploid to haploid.
- Which phase follows prophase I in meiosis?
- Metaphase I. Homologous pairs align at the cell's equatorial plane.
- Define chiasma.
- Point where crossing over occurs between chromatids. Visible evidence of genetic recombination during prophase I.
- What is synapsis in meiosis?
- The pairing of homologous chromosomes during prophase I. Enables crossing over between homologous chromosomes.
- What is the result of fertilization in terms of chromosomes?
- A diploid zygote is formed. Restores diploid chromosome number from two haploid gametes.
- Identify the phase where homologous chromosomes separate.
- Anaphase I. First reductional division of meiosis occurs here.
- What is a tetrad in meiosis?
- A group of four chromatids formed by synapsis of homologous chromosomes. Also called a bivalent; where crossing over occurs.
- What is a gamete?
- A haploid cell used in sexual reproduction. Sex cells with half the parental chromosome number.
- What is independent assortment?
- Random distribution of homologous chromosomes during meiosis. Each chromosome pair segregates independently at metaphase I.
- Identify the phase in which spindle fibers attach to kinetochores.
- Metaphase I and Metaphase II. Spindle fibers attach to ensure proper chromosome movement.
- How many daughter cells are produced in meiosis?
- Four daughter cells are produced. One diploid cell divides twice to create four haploid cells.
- Identify the two main phases of meiosis.
- Meiosis I and Meiosis II. First division separates homologs, second separates sister chromatids.
- How does meiosis contribute to genetic diversity?
- Through crossing over and independent assortment. Two key mechanisms create genetic variation in offspring.
- What is the role of centromeres in meiosis?
- Connect sister chromatids; site for spindle attachment. Essential for proper chromosome segregation during division.