Vocabulary: gamete, egg, sperm, fertilization, meiosis.
Review:
1. A gamete (haploid)
2. A sperm and an egg combine to form a new cell.
3. Meiosis produces 4 1n gametes instead of 2 2n cells. It involves 2 divisions after DNA is copied, rather than 1 division after DNA is copied.
4. ProphaseI: one cell contains twice usual number of chromosomes for species; prophase II; two cells each with two copies of one homolog of each chromosome pair.
5. Meiosis: produces 4 1n cells, 2 divisions; mitosis: produces 2 2n cells, one division; both: DNA copied, chromosomes divide, new cells form.
6. One cell divides twice, so one cell produces four. The cells are 1n because DNA was only copied only once.
It is good to know that when DNA condenses,each chromosome find his homolog, also that the maching pairs of chromosomes hols equivalent genetic information.
ResponderEliminarMiss i like the video , i think it is very helpful.
Erica Gonzalez #13 7 A
The 2 homologs (one from mother and one from the father) treat genes in a proces called "crossing over" and with that process, it forms new hybrid chromosomes.
ResponderEliminarHaploid cells: are cells that carry half of the genetic information.
Sofia Kharissova 7A #2