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Diagram a cell with four chromosomes going through meiosis.

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Diagram a cell with four
chromosomes going through
meiosis.
Mitosis vs. Meiosis
Mitosis
• One division
• 2 diploid
daughter cells
• Identical to
parent cell
http://highered.mcgrawhill.com/sites/0072495855/stu
dent_view0/chapter28/animati
on__how_meiosis_works.html
Mitosis
• Two divisions
• 4 haploid
daughter cells
• Genetically
different from
parent cell
Nucleus
chromosomes
• Get one small, one medium and one large of
each color chromosome.
• What do the colors represent?
• The Beads?
• Pair up chromatids with same size and color
•
•
•
•
Pair up chromatids with same size and color
What does this represent?
What stage?
Haploid or diploid?
• Match homologous chromosomes
• Match homologous chromosomes
• What are homologous chromosomes.
Carry the
same traits
Each
homologous
pair has one
from each
parent
Demonstrate crossing over during prophase.
Demonstrate crossing over during prophase.
• Demonstrate metaphase
Demonstrate metaphase
• Demonstrate the first division
• Anaphase I and Telophase I
• Demonstrate the first division
• Anaphase I and Telophase I
• Move your cells through the second division.
• Move your cells through the second division.
• How many daughter cells do you have?
• Are the daughter cells haploid or diploid?
• Are the cells genetically Identical or different
from the parent cell?
4
Haploid
Daughter Cells
Parent
Cell
Daughter Cells
Possible Combinations of
chromosomes
n
2
What does n represent?
What was our haploid number of chromosomes?
What is the possible number of combinations?
8
In people possible 8388608 combinations.
•
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter28/animation__random_orientation_
of_chromosomes_during_meiosis.html
Sexual Reproduction
•
•
•
•
Combines the genetic material of two organisms.
Introduces new gene combinations in a population.
Leads to genetic Variability in the population.
Gametes produced in meiosis fuse to form a zygote.
– Gamete-reproductive cell that contains the haploid set of
chromosomes…..sperm and egg
– Zygote- Cell formed from fusion of gametes that contains
the diploid set of chromosomes.
Sexual Reproduction
Methods
• External Fertilization: the eggs are fertilized
outside of the body
• Internal Fertilization: the eggs are fertilized
within the female reproductive tract
• Conjugation: cells exchange genetic material
– Prokaryotes
Asexual Reproduction
•
•
•
•
•
Offspring arise from a single parent.
Offspring genetically identical to parent.
More likely to inherit mutations.
Leads to less diversity.
Mitosis
Asexual Reproduction
Methods
• Budding
– offspring grows out of the body
of the parent.
• Spores
– a reproductive cell capable
of developing into a new individual
without fusion with
another reproductive cell.
• Fission
– separation of the body into
two new bodies
Quiz
• Compare and contrast sexual and asexual
reproduction.
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