AP Biology Penguins Topic 5

Meiosis Overview

• Phases of meiosis I: Prophase I, Metaphase I, Anaphase I, Telophase I.
• Meiosis I reduces chromosome number by half, transitioning from diploid to haploid.
• Phases of meiosis II: Prophase II, Metaphase II, Anaphase II, Telophase II.
• Meiosis II separates sister chromatids and maintains haploid status.

Differences Between Meiosis I and II

• Chromosome crossing over occurs in Prophase I but not in Prophase II.
• Meiosis I separates homologous chromosomes; Meiosis II separates sister chromatids.
• Meiosis I results in haploid cells; Meiosis II results in haploid cells from haploid precursors.

Meiosis and Genetic Diversity

• Anaphase I results in reduction of chromosome number.
• Daughter cells from meiosis are genetically different from the parent cell due to crossing over and independent assortment.
• Crossing over is the exchange of genetic material between homologous chromosomes, increasing genetic variability.
• Independent assortment involves the random distribution of homologous chromosomes, contributing to genetic diversity.
• Random fertilization allows for any sperm to fuse with any egg, further increasing genetic diversity.

Mitosis Overview

• Phases of mitosis: Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
• Daughter cells produced by mitosis are identical to the parent cell.

Comparisons of Mitosis and Meiosis

• Mitosis produces 2 identical daughter cells, while meiosis produces 4 unique daughter cells.
• Mitosis results in diploid cells; meiosis results in haploid cells.
• Both processes involve the separation of chromosomes and cytokinesis.

Chromosomal Behavior During Meiosis

• Homologous chromosomes separate during Anaphase I via spindle fibers pulling apart at the kinetochores.
• Daughter cells receive both maternal and paternal chromosomes through random assortment in meiosis I.

Genetic Information and Evolution

• DNA is the carrier of genetic information, present in all living organisms.
• Ribosomes are found in all life forms, indicating a shared ancestry.
• A shared genetic code and metabolic process (cellular respiration) demonstrate common ancestry.

Genetic Laws

• The law of independent assortment states that genes for different traits are inherited independently.
• The law of segregation indicates that allele pairs separate during gamete formation and unite randomly during fertilization.
• Expected ratio of a monohybrid cross is 3:1.
• Expected ratio of a dihybrid cross is 9:3:3:1.
• The probability of genotype AaBbCCDd in a tetrahybrid cross is 1/32.

This quiz covers the key phases and roles of meiosis I and II, central concepts for understanding cellular division in biology. Perfect for AP Biology students preparing for exams. Use these flashcards to enhance your study and retention of these crucial biological processes.