Part 3: Meiosis 1 and Meiosis 2 6. Name the stage of meiosis 1 where each of the
ID: 254029 • Letter: P
Question
Part 3: Meiosis 1 and Meiosis 2 6. Name the stage of meiosis 1 where each of the following occurs: Homologous chromosomes pair and form synapses Bivalents align at metaphase plate Two complete daughter cells form Nuclear membrane disappears Nuclear membrane reforms Chromosomes move to separate pole View the meiosis 1 and 2 animation 7. At the end of meiosis 2, each cell contains how many chromosomes? Part 4: A Review of Meiosis 8. Name 2 errors that can occur during meiosis. Phase Diagrams Label these phasesExplanation / Answer
6.Hoologous chromosomes pair and form synapses- zygotene stage of prophase I
Bivalents align at metaphase plate-metaphase I
Two complete daughter cells form- Telophase I
Nuclear membrane disappears- Diakinesis of Prophase I
Nuclear membrane reforms- telophase I
Chromosomes move to separate poles- Anaphase I
7. At the end of meisosi II each cell contains half the number of chromosomes as theoriginal parent cell. So if for e.g. the cell started with 8 chromosomes or 4 pairs after meiosis I it will have 4 chromosomes or 2 pairs of chromosomes.
8. If the chromosomes do not segregate correctly during meiosis, the resulting gametes can have extra or less chromosomes. Downs syndrome, for example, oocurs when the chromosomes do not segregate correctly and results in an extra copy of chromosome 21 also known as trisomy 21.
Another way in which errors can occur is during replication of the chromosomes. Sometimes during the copying of the DNA, errors may occur and this will result in mutations or altered sequences in the DNA.
Phase diagrams
The one on the left is metaphase I in which pairing of homologous chromosomes takes place.
The diagram on the right shows anaphase I in which the homologous chromosomes are separted to opposite poles of the cell.