Dictionary of Mitosis & Meiosis Flashcards
Aneuploidy
When the chromosomes in meiosis divided unevenly and one egg/sperm ends up with too much DNA while the other has too little.
Aster
The formation that the extra unattached spindle fibers make as they radiate outwards in a “sun” shape from the centrioles.
Centriole
A cell organelle present in animal cells that forms the asters and spindle fibers during mitosis and meiosis.
Centromere
Region on the chromosome where the kinetochore is built and where the chromatids are attached together.
Centrosome
Region in the cell where the centrioles are found.
Chromatid
One of the identical copies of DNA made during DNA replication.
Chiasmata
Regions/locations on the tetrad where synapsis (crossing over) occurs in Prophase I of Meiosis.
Chromatin
The form DNA takes in the nucleus of a cell when it is not dividing.
Chromosome
The coiled up form of DNA used to divide up DNA during both mitosis and meiosis.
Cytokinesis
The division of cytpplasm at the end of telophase.
Gamete
A sex cell (eggs, sperm)
Diploid
A full set of DNA. 1 allele from each parent. Somatic cells.
DNA Polymerase
One of the enzymes that assists DNA replication (builds the DNA from RNA primer block)
Haploid
1/2 a set of DNA, only 1 of your two alleles. (eggs, sperm)
Homologous chromosme
Two matching chromosomes that make up a tetrad. 1 chromosome with DNA from Mom and 1 from Dad, 4 chromatids in total.
Kinetochore
Structure on the chromosome found at the centromere where the spindle fibers attach.
Random assortment
The process in Metaphase I where Mom and Dad tetrads line up and go to separate sides. (one left or right)
Somatic
A body cell (skin cell)
Synapsis
The exchange of Mom and Dad genes during Prophase I of Meiosis (crossing over)
Tetrad
The structure caused by the pairing of homologous chromosomes in Prophase I of Meiosis.
When does DNA replication happen in terms of Meiosis and Mitosis
At the beginning of each.
The two levels of variation in meiosis are (with specific times):
- Synapsis (crossing over) in Prophase I
- Random Assortment in Metaphase I
