Mitosis & Meiosis

1. Mitosis and Meiosis
Diploid (2n): 2 sets of homologous chromosomes
Haploid (1n): 1 single set of homologous chromosomes.
This cell has 2 pairs of chromosomes; 1 long, 1 short. There
are two sets of 2 similar (homologous) chromosomes.
Ploidy = diploid, 2n
# of chromosomes = 4
# of chromatids = 4
This cell has 2 pairs of duplicated homologous
chromosomes; 1 long, 1 short.
Ploidy = diploid, 2n
# of chromosomes = 4
# of chromatids = 8
This cell has 2 chromosomes; 1 long, 1 short. There is
only 1 copy of each chromosome, so it is haploid.
Ploidy = haploid, 1n
# of chromosomes = 2
# of chromatids = 2
This cell has 2 duplicated chromosomes; 1 long, 1 short.
There is only 1 copy of each chromosome, so it is
haploid.
Ploidy = haploid, 1n
# of chromosomes = 2
# of chromatids = 4

2. This is a diploid cell
in metaphase and anaphase of mitosis. In the metaphase cell, there are 4
chromosomes (8 chromatids) total and two sets of homologous chromosomes that are
duplicated. In the anaphase cell, there are 8 chromosomes. The resulting daughter
cells will also be diploid and genetically identical to the mother cell.
This is a haploid cell in metaphase and anaphase of mitosis. There are 2 chromosomes
(4 chromatids); 1 big chromosome, 1 small chromosome in the metaphase cell. In the
anaphase cell, there are 4 chromosomes present. The resulting daughter cells would
be halploid and genetically identical to the mother cell.
There are two divisions in meiosis. The cell entering meiosis is diploid. In meiosis
homologous chromosomes pair (allows crossing over of genetic material), but
homologous do not pair in mitosis. Another difference is that after the first meiotic
division, the cells do not reenter interphase and DNA is not replicated.
In metaphase 1 of meiosis, bivalents orient at the metaphase plate and homologous are
paired. Each chromosome of a homologous pair attaches to fibers from opposite poles.

3. The sister chromatids attach to fibers from the same pole. In anaphase 1, the
centromere does not divide and homologous chromosomes move to opposite poles.
This is the separation of
homologous chromsomes.
These are the products of the first
meiotic division. Only 1 of each
chromosome (long and short) is
present, therefore the daughter
cells produced from the first meiotic
division are haploid.
In between meiosis 1 and 2, the DNA does not replicate and the starting cells are
haploid.
In metaphase 2, the chromosomes
align at the metaphase plate and sister
chromatids attach to spindle fibers
from opposite poles.
In anaphase 2, the centromeres divide
and chromatids move to opposite
poles. This is the separation of sister
chromatids.
The daughter cells produced are
also haploid, having only 1 of each
chromosome (long and short).