Meiosis and Chromosomal Abnormalities Flashcards
What is Meiosis?
The Process of forming haploid cells.
What do most haploid cells?
They are gametes.
What is the process of meiosis involve?
The replication of DNA followed by 2 sets of cell division so the daughter cells contain only one member of each homologous pair and one sex chromosome.
What happens prior to meiosis?
Single stranded chromosomes are replicated to become 2 identical chromatids.
Meiosis steps…
- Prophase I
- Metaphase I
- Anaphase I
- Telophase I
- Prophase II
- Metaphase II
- Anaphase II
- Telophase II and Cytokinesis
What happens in prophase I…
The DNA condenses and the chromosomes appear. spindles start to form and similar chromosomes pair. Adjacent chromatids wrap around each other. The nuclear membrane starts to break down towards the very end.
What is Synapsis?
The act of similar chromosomes pairing.
In prophase where to the chromatids wrap around..
The Chiasmata.
What is Crossing over recombination?
In prophase 1… it is the chance of chromosomes breaking and swapping pieces.
What happns during Metaphase I…
The breakdown of nuclear membrane completed. Spindle fibers attach to the centromeres of chromosomes. Homologous pairs move to the equator of spindle which is now fully formed.
What happens during Anaphase I…
Spindles retract towards poles of the cell causing pairs to separate.
What happens during Telophase I…
Chromosomes unwind. spindle breakdown and a nuclear membrane forms around each set of chromosomes.
What happens during Prophase II…
New spindle forms and DNA condenses. Chromosomes appear and are double stranded but the daughter cells are haploid.
What happens during Metaphase II…
Chromosomes consisting of sister chromatids line up in a single file across equator of cell. Spindle is corrected to the centromere of chromosome.
What happens during Anaphase II…
Spindle fibers contract and pull sister chromatids to the poles of the cell.