Question

meiosis i overview
goal of meiosis i: separate homologous chromosomes
at the end of meiosis i, the cell becomes (haploid/diploid).
each chromosome still has sister chromatids attached.
meiosis ii overview
goal of meiosis ii: separate sister chromatids
meiosis ii produces 4 genetically unique haploid cells.
how meiosis creates variation
genetic variation comes from three main events:

1. crossing over (prophase i)
2. independent assortment (metaphase i)
3. random (fertilization)

creating genetic variation
crossing over = chromatids swap genes.
independent assortment = chromosomes line up.
random fertilization = any can meet any.
crossing over (prophase i)
homologous chromosomes pair to form a.
chromatids can and exchange dna.
this creates new combinations of.
happens only during.
independent assortment (metaphase i)
homologous pairs line up at the cells equator.
each gamete receives a different mix of.
this creates millions of possible.
independent assortment - extended
chromosomes line up at the of the cell.
it is random which side the and chromosomes line up.

Explanation:

• Meiosis I: The goal is to separate homologous chromosomes. At the end, the cell becomes haploid (as the chromosome number is halved compared to the parent cell). Each chromosome still has sister chromatids attached (since sister - chromatid separation occurs in Meiosis II).
• Meiosis II: The goal is to separate sister chromatids. It produces 4 genetically unique haploid cells (starting from 2 haploid cells after Meiosis I, each of those divides again).
• Genetic Variation:
• Crossing Over (Prophase I): Homologous chromosomes pair to form a tetrad. Chromatids can break and exchange DNA. This creates new combinations of alleles. It happens only during Prophase I of Meiosis.
• Independent Assortment (Metaphase I): Homologous pairs line up randomly at the cell's equator. Each gamete receives a different mix of maternal and paternal chromosomes. This creates millions of possible chromosome combinations. Chromosomes line up at the equator of the cell. It is random which side the maternal and paternal chromosomes line up.
• Random Fertilization: Any sperm can meet any egg.

Answer:

• Meiosis I:
• Goal: separate homologous chromosomes
• Cell state: haploid
• Chromosome feature: sister chromatids attached
• Meiosis II:
• Goal: separate sister chromatids
• Cell number: 4
• Genetic Variation:
• 1. Crossing over (Prophase I)
• 2. Independent assortment (Metaphase I)
• 3. Random fertilization
• Crossing Over:
• Structure: tetrad
• Chromatid action: break
• Result: alleles
• Occurrence: Prophase I
• Independent Assortment:
• Line - up manner: randomly
• Chromosome mix: maternal and paternal chromosomes
• Result: chromosome combinations
• Extended:
• Location: equator
• Chromosome types: maternal, paternal