Download meiosis

Chapter 13
Meiosis and Sexual
Life Cycles
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 13-3
What is the
value of a
prenatal
diagnosis used
in karyotyping?
APPLICATION
TECHNIQUE
5 µm
Pair of homologous
replicated chromosomes
Centromere
Sister
chromatids
Metaphase
chromosome
Fig. 13-5
Key
Haploid (___)
Diploid (___)
Distinguish
between a
haploid and
Diploid stage in
the life cycle of
a human.
Egg (____)
Sperm (____)
Complete the
chart.
Ovary
What is
Fertilization?
What is the
significance of
Fertilization as
it relates to this
diagram
Testis
__________
zygote
(2n = ___)
_________________&
__________________
_______________
__________(____= 46)
Fig. 13-6 What
is the common feature of all three cycles? How do they differ?
Key
Haploid (n)
n
Gametes
n
Mitosis
n
n
MEIOSIS
FERTILIZATION
Diploid
multicellular
organism
(a) Animals
Zygote
2n
Mitosis
Mitosis
n
Spores
Mitosis
Mitosis
n
n
n
n
MEIOSIS
2n
Haploid unicellular or
multicellular organism
Haploid multicellular organism
(gametophyte)
Diploid (2n)
n
Gametes
n
n
Gametes
FERTILIZATION
MEIOSIS
2n
Diploid
multicellular
organism
(sporophyte)
n
2n
Mitosis
(b) Plants and some algae
Zygote
FERTILIZATION
2n
Zygote
(c) Most fungi and some protists
Fig. 13-7-3
Interphase
Homologous pair of chromosomes
in diploid parent cell
Re-Draw the cells
in this figure
using a simple
double helix to
represent each
DNA molecule.
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I
1 Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes
Meiosis II
2 Sister chromatids
separate
Haploid cells with unreplicated chromosomes
Fig. 13-8 Distinguish
between the key Meiosis I & Meiosis II
Three events are unique to meiosis I describe these events
What event occurs when chromosomes are in synapsis? How does this affect
the resultant gametes?
Metaphase I
Prophase I
Centrosome
(with centriole pair)
Sister
chromatids
Chiasmata
Spindle
Prophase II
Metaphase II
Anaphase II
Telophase II and
Cytokinesis
Sister chromatids
remain attached
Centromere
(with kinetochore)
Metaphase
plate
Homologous
chromosomes
separate
Homologous
chromosomes
Fragments
of nuclear
envelope
Telophase I and
Cytokinesis
Anaphase I
Microtubule
attached to
kinetochore
Cleavage
furrow
Sister chromatids
separate
Haploid daughter cells
forming
Fig. 13-9a Summarize
the key properties between Mitosis and Meiosis
MITOSIS
MEIOSIS
Parent cell
Chromosome
replication
Prophase
Chiasma
Chromosome
replication
Prophase I
Homologous
chromosome
pair
2n = 6
Replicated chromosome
MEIOSIS I
Metaphase
Metaphase I
Anaphase
Telophase
Anaphase I
Telophase I
Haploid
n=3
Daughter
cells of
meiosis I
2n
Daughter cells
of mitosis
2n
MEIOSIS II
n
n
n
n
Daughter cells of meiosis II
Fig. 13-11-3 What
is independent assortment? How can you determine the
number of possible combinations when chromosomes sort independently?
Possibility 2
Possibility 1
Two equally probable
arrangements of
chromosomes at
metaphase I
Metaphase II
Daughter
cells
Combination 1 Combination 2
Combination 3 Combination 4
Fig. 13-12-5 What
is crossing
over?
What might be
the
evolutionary
significance
of the switch
from asexual
to sexual
reproduction
that occurs in
some
organisms
when the
environment
becomes
unfavorable.
Prophase I
of meiosis
Pair of
homologs
Nonsister
chromatids
held together
during synapsis
Chiasma
Centromere
TEM
Anaphase I
Anaphase II
Daughter
cells
Recombinant chromosomes
• Crossing over adds even more variation
• Each zygote has a unique genetic identity
Animation: Genetic Variation
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings