Chromosomal Segregation Flashcards
Identical copies of DNA formed through DNA replication; segregate during mitosis and meiosis II
sister chromatids
Contain the same genes in the same order, but may contain different alleles. One homolog is inherited from each parent.
Segregate during meiosis I
Homologous chromosomes
Growth phases
G1 and G2
DNA is replicated (sister chromatid made)
S phase
Cells are not actively dividing
G0
Order of cell cycle
G1, (G0), S, G2, M
Number of complete sets of chromosomes in a cell
Diploid (2n)
Polyploid (i.e. 8n)
Haploids (n)
Ploidy “n”
- Give rise to gametes (sperm and eggs)
- Undergo mitosis and meiosis
- Pass genetic information on to the next generation
Germ-line cells
- All cells that are not germ-line
- Undergo mitosis, not meiosis
- Pass genetic information on to daughter cells
- Do not pass genetic information to next generation
Somatic Cells
Sister Chromatids separate
Creates 2 Identical daughter cells
1. Prophase
2. Metaphase
3. Anaphase (sister chromatids separate)
4. Telophase
2n —> 2n
Mitosis
Cell division that produces gametes, 2 parts
Meiosis
The reductional division (homologous chromosomes are separated)
2n —> 1n
Meiosis I
The equational division (sister chromatids are separated)
Meiosis II
(Diploid, 2n)
Early prophase:
- Synapsis, 4 copies of the DNA (w/ sister chromatids) are very tightly packed
- Crossing over/ recombination
Late prophase:
- Chromosomes are condensed and homologous chromosomes are visible as bivalents or tetrads (4 copies of DNA)
- spindle forms
- nuclear envelope fragments
Prophase I
(Diploid, 2n)
- Homologous pairs align along the equator of the cell as bivalents
Metaphase I
