Mitosis vs. Meiosis

Interphase: Growth 1 (G1), Synthesis (S - DNA replication), Growth 2 (G2)

Mitosis (equal division of the nucleus) or Meiosis (division of the nucleus resulting in half the number of chromosomes)

Cytokinesis: division of the cytoplasm

Asexual cell reproduction: Makes identical daughter cells

Happens in somatic cells (any cell except gametes)

DNA replicated during interphase

Cell divides once creating 2 identical diploid (2n) daughter cells

In a diploid cell there are 2 copies of each chromosome (2n)

Homologous pairs have the same genes in the same order, so they will be the same length.

1 copy came from the father

1 copy came from the mother

Meiosis: homologous pairs separate (separation divides chromosome number in half = haploid (n) cell)

Mitosis: no pairing and separation of homologous pairs

Sexual cell reproduction: Results in variation (4 genetically unique daughter cells)

Happens in gametes (produces egg or sperm)

DNA replicated during interphase

Cell divides twice producing 4 haploid (n) daughter cells

Division 1: separates homologous pairs

Division 2: separates sister chromatids (double stranded to single stranded chromosomes)

Both: Parent cell is diploid (2n) and DNA replication happens during the S phase of interphase before either mitosis or meiosis.

Mitosis: 1 Division - Sister chromatids separate making 2 identical diploid (2n) daughter cells.

Meiosis: 2 Divisions - unique haploid (n) daughter cells produced.

Variation is caused during the first division of meiosis.

Prophase 1 - Crossing Over: homologous pairs exchange pieces (swap gene variations)

Metaphase 1 to Anaphase 1 - Independent assortment and separation of homologous pairs.

Meiosis results in unique egg and sperm, which egg combines with which sperm is random.

The image is tracking 1 gene, and there are 3 possible outcomes in the children.

Human's have over 20,000 genes

With the same 2 parents there are millions of possible gene combinations.