Download Meiosis - Tolar ISD

What are we
learning today?
1. What are the phases of meiosis
and what happens during each
phase?
2. What is the significance of
meiosis to sexual reproduction?
What are we
learning today?
1. How are mitosis and meiosis
similar?
2. How are mitosis and meiosis
different?
Meiosis
• Somatic cells : have
two sets of
chromosomes.
• One from each
parent.
• Includes all cells in
your body except
gametes
• Somatic cells are
diploid.
Cell basics
Cell basics
• Diploid : contains
two sets of
chromosomes
• The two
chromosomes in
each pair are called
homologous.
• Humans have 23
pair of homologous
chromosomes.
Cell basics
• Autosomes : all
chromosomes in the
cell except the sex
chromosomes X & Y
• Humans have 22
pair of autosomes
and 1 pair of sex
chromosomes.
Cell basics
• For reproduction to
occur, the
chromosome
number must be
reduced by ½.
• Remember, in a
somatic cell, one
chromosome came
from each parent
• Meiosis : cell
division which
results in the
production of
gametes with half
the number of
chromosomes
• When fertilization
occurs, the zygote
will contain the full
set of homologous
chromosomes
Meiosis
Meiosis
• The cells produced from meiosis are haploid
• Haploid : cells with one copy of each chromosome.
• Gametes are haploid.
Meiosis
• The phases of
meiosis are similar
to mitosis
• Meiosis consists of
2 divisions of the
cell.
• The result is four
daughter cells.
Stages of
Meiosis
• The stages of
meiosis are named
prophase,
metaphase,
anaphase,
telophase
• The 2 cell divisions
are distinguished
by “I” or “II”
Result of
Meiosis
• Four haploid cells
called gametes
• Four daughter cells
not identical to the
parent cell.
• Gametes are
necessary for
sexual reproduction
What are we
learning today?
1. What are the phases of meiosis
and what happens during each
phase?
2. What is the significance of
meiosis to sexual reproduction?
What are we
learning today?
1. How are mitosis and meiosis
similar?
2. How are mitosis and meiosis
different?