Meiosis Flashcards
Concept 3 (23 cards)
Somatic Cells
body cells
-diploid (2n)
Gametes
sex cells
-haploid (n)
Diploid Cells
2 full sets of chromosomes
-1 set per parents
Haploid Cells
1 full set of chromosomes
-1 set of both mom + dad’s chromosomes
Autosomes
carry traits that make you who you are
-1st 22 pairs of chromosomes
Sex Chromosome
carry traits that make you who you are AND determine your biological sex
-23rd pair of chromosomes (X or Y)
Meiosis Diagram
Nothing: 2n: Duplicated
Meiosis I: n: Duplicated
Meiosis II: n: Unduplicated
Homologous chromosomes
chromosome pairs that have the same type of genes
-1 from mom
-1 from dad
Sister chromatids
2 identical copies of the same chromosome
Before Meiosis I
Interphase: growth phase G1, S, G2
-at end of interphase, cell has Duplicated 2 copies of each chromosome
Meiosis I
Separation of homologous chromosomes
-diploid Duplicated —-> haploid duplicated
Meiosis I: Prophase 1
-nuclear membrane breaks down
-centrioles separate and make spindle fibers
-homologous chromosomes pair up and become visible
-CROSSING OVER: chromosomes cross over and swap pieces of DNA, creates new combo of genes
Meiosis I: Metaphase 1
homologous chromosomes are lined up in the middle in pairs
Meiosis I: Anaphase 1
homologous chromosomes pairs separate
-sister chromatids are still attatched
Meiosis I: Telophase 1
-chromosomes gather at poles
-nuclear membranes may reform
-Cytokinesis: cytoplasm divides into 2 cells
End Result of Meiosis I
2 haploid daughter cells with Duplicated chromosomes that are different from the sets in the original diploid cell
Meiosis II
-Skip Interphase
-Separation of sister chromatids, Duplicated chromosomes divide into Unduplicated individual chromosomes
Meiosis II: Prophase 2
-nuclear membrane breaks down (if it reformed)
-spindle fibers form and attach to centromeres of the sister chromatids
Meiosis II: Metaphase 2
-sister chromatids line up in the middle of the cells single-file
Meiosis II: Anaphase 2
-sister chromatids separate and are pulled away to each side of the cells
Meiosis II: Telophase 2
-nuclear membranes form around each set of chromosomes
-spindle fibers dissolve
-cytokinesis
End Result of Meiosis II
4 undifferentiated haploid daughter cells that are genetically unique
