19. Figure 13.4
Sister chromatids
of one duplicated
chromosome
Key
Maternal set of
chromosomes (n = 3)
Paternal set of
chromosomes (n = 3)
Key
2n = 6
Centromere
Two nonsister
chromatids in
a homologous pair
Pair of homologous
chromosomes
(one from each set)
26. Figure 13.6
Key
Haploid (n)
Diploid (2n)
Gametes
MEIOSIS FERTILIZATION
Zygote
Mitosis
Diploid
multicellular
organism
(a) Animals
n
n
n
2n 2n
2n
2n
2n
n n
n
n
n
n
n
n
n
n
MEIOSIS
MEIOSIS
FERTILIZATION
FERTILIZATION
Mitosis Mitosis
Mitosis
Mitosis Mitosis
Gametes
Spores
Gametes
Zygote
Zygote
Haploid multi-
cellular organism
(gametophyte)
Diploid
multicellular
organism
(sporophyte)
Haploid unicellular or
multicellular organism
(b) Plants and some algae (c) Most fungi and some protists
32. Figure 13.6c
Key
Haploid (n)
Diploid (2n)
2n
n n
n
n
n
MEIOSIS FERTILIZATION
Mitosis Mitosis
Gametes
Zygote
Haploid unicellular or
multicellular organism
(c) Most fungi and some protists
36. Figure 13.7-1
Pair of homologous
chromosomes in
diploid parent cell
Duplicated pair
of homologous
chromosomes
Chromosomes
duplicate
Sister
chromatids
Diploid cell with
duplicated
chromosomes
Interphase
37. Figure 13.7-2
Pair of homologous
chromosomes in
diploid parent cell
Duplicated pair
of homologous
chromosomes
Chromosomes
duplicate
Sister
chromatids
Diploid cell with
duplicated
chromosomes
Homologous
chromosomes separate
Haploid cells with
duplicated chromosomes
Meiosis I
1
Interphase
38. Figure 13.7-3
Pair of homologous
chromosomes in
diploid parent cell
Duplicated pair
of homologous
chromosomes
Chromosomes
duplicate
Sister
chromatids
Diploid cell with
duplicated
chromosomes
Homologous
chromosomes separate
Haploid cells with
duplicated chromosomes
Sister chromatids
separate
Haploid cells with unduplicated chromosomes
Interphase
Meiosis I
Meiosis II
2
1
41. Figure 13.8
MEIOSIS I: Separates homologous chromosomes
Prophase I Metaphase I Anaphase I
Telophase I and
Cytokinesis
Centrosome
(with centriole pair)
Sister
chromatids
Chiasmata
Spindle
Homologous
chromosomes
Fragments
of nuclear
envelope
Duplicated homologous
chromosomes (red and blue)
pair and exchange segments;
2n = 6 in this example.
Centromere
(with kinetochore)
Metaphase
plate
Microtubule
attached to
kinetochore
Chromosomes line up
by homologous pairs.
Sister chromatids
remain attached
Homologous
chromosomes
separate
Each pair of homologous
chromosomes separates.
Cleavage
furrow
Two haploid cells
form; each chromosome
still consists of two
sister chromatids.
MEIOSIS I: Separates sister chromatids
Prophase II Metaphase II Anaphase II
Telophase II and
Cytokinesis
Sister chromatids
separate
Haploid daughter
cells forming
During another round of cell division, the sister chromatids finally separate;
four haploid daughter cells result, containing unduplicated chromosomes.
42. Figure 13.8a
Prophase I Metaphase I Anaphase I Telophase I and
Cytokinesis
Centrosome
(with centriole pair)
Sister
chromatids
Chiasmata
Spindle
Homologous
chromosomes
Fragments
of nuclear
envelope
Duplicated homologous
chromosomes (red and blue)
pair and exchange segments;
2n = 6 in this example.
Centromere
(with kinetochore)
Metaphase
plate
Microtubule
attached to
kinetochore
Chromosomes line up
by homologous pairs.
Sister chromatids
remain attached
Homologous
chromosomes
separate
Each pair of homologous
chromosomes separates.
Cleavage
furrow
Two haploid
cells form; each
chromosome
still consists
of two sister
chromatids.
46. Figure 13.8b
Prophase II Metaphase II Anaphase II
Telophase II and
Cytokinesis
Sister chromatids
separate
Haploid daughter
cells forming
During another round of cell division, the sister chromatids finally separate;
four haploid daughter cells result, containing unduplicated chromosomes.
57. Figure 13.9
Prophase
Duplicated
chromosome
MITOSIS
Chromosome
duplication
Parent cell
2n = 6
Metaphase
Anaphase
Telophase
2n 2n
Daughter cells
of mitosis
MEIOSIS
MEIOSIS I
MEIOSIS II
Prophase I
Metaphase I
Anaphase I
Telophase I
Haploid
n = 3
Chiasma
Chromosome
duplication Homologous
chromosome pair
Daughter
cells of
meiosis I
Daughter cells of meiosis II
n n n n
SUMMARY
Property Mitosis Meiosis
DNA
replication
Number of
divisions
Synapsis of
homologous
chromosomes
Number of
daughter cells
and genetic
composition
Role in the
animal body
Occurs during interphase before
mitosis begins
One, including prophase, metaphase,
anaphase, and telophase
Does not occur
Two, each diploid (2n) and genetically
identical to the parent cell
Enables multicellular adult to arise from
zygote; produces cells for growth, repair,
and, in some species, asexual reproduction
Occurs during interphase before meiosis I begins
Two, each including prophase, metaphase, anaphase,
and telophase
Occurs during prophase I along with crossing over
between nonsister chromatids; resulting chiasmata
hold pairs together due to sister chromatid cohesion
Four, each haploid (n), containing half as many
chromosomes as the parent cell; genetically different
from the parent cell and from each other
Produces gametes; reduces number of chromosomes
by half and introduces genetic variability among the
gametes
58. Figure 13.9a
Prophase
Duplicated
chromosome
MITOSIS
Chromosome
duplication
Parent cell
2n = 6
Metaphase
Anaphase
Telophase
2n 2n
Daughter cells
of mitosis
MEIOSIS
MEIOSIS I
MEIOSIS II
Prophase I
Metaphase I
Anaphase I
Telophase I
Haploid
n = 3
Chiasma
Chromosome
duplication Homologous
chromosome pair
Daughter
cells of
meiosis I
Daughter cells of meiosis II
n n n n
59. Figure 13.9b
SUMMARY
Property Mitosis Meiosis
DNA
replication
Number of
divisions
Synapsis of
homologous
chromosomes
Number of
daughter cells
and genetic
composition
Role in the
animal body
Occurs during interphase before
mitosis begins
One, including prophase, metaphase,
anaphase, and telophase
Does not occur
Two, each diploid (2n) and genetically
identical to the parent cell
Enables multicellular adult to arise from
zygote; produces cells for growth, repair,
and, in some species, asexual reproduction
Occurs during interphase before meiosis I begins
Two, each including prophase, metaphase, anaphase,
and telophase
Occurs during prophase I along with crossing over
between nonsister chromatids; resulting chiasmata
hold pairs together due to sister chromatid cohesion
Four, each haploid (n), containing half as many
chromosomes as the parent cell; genetically different
from the parent cell and from each other
Produces gametes; reduces number of chromosomes
by half and introduces genetic variability among the
gametes
72. Figure 13.11-2
Prophase I
of meiosis
Nonsister chromatids
held together
during synapsis
Pair of homologs
Chiasma
Centromere
TEM
73. Figure 13.11-3
Prophase I
of meiosis
Nonsister chromatids
held together
during synapsis
Pair of homologs
Chiasma
Centromere
TEM
Anaphase I
74. Figure 13.11-4
Prophase I
of meiosis
Nonsister chromatids
held together
during synapsis
Pair of homologs
Chiasma
Centromere
TEM
Anaphase I
Anaphase II
75. Figure 13.11-5
Prophase I
of meiosis
Nonsister chromatids
held together
during synapsis
Pair of homologs
Chiasma
Centromere
TEM
Anaphase I
Anaphase II
Daughter
cells
Recombinant chromosomes
81. Prophase I: Each homologous pair undergoes synapsis
and crossing over between nonsister chromatids with
the subsequent appearance of chiasmata.
Metaphase I: Chromosomes line up as homologous
pairs on the metaphase plate.
Anaphase I: Homologs separate from each other; sister
chromatids remain joined at the centromere.
Figure 13.UN01