9B: Room 206
room
Andre
Zuri
Whitney
Front of
Nancy
Natalie N
Julian
Leela
Leslie
Patrick
Larissa
Jamesley Natalie G
Emperor
Ricardo
Aser
McHenley
Grace
Harold
Israel
Emily
Tom
Trevon
Bio 9B: Monday, 3.14.11
Title: Introduction to Meiosis & Genetic Inheritance

Homework:




Do Now:


Go to the Biology blog (phascience.wordpress.com) and do the notetaking assignment.
Then answer the questions on the back of assignment sheet (also on
powerpoint)
Finish the Karyotyping Activity & Questions if you didn’t finish it in class.
What is a chromosome?
Today’s Objectives:
 Describe the difference between asexual and sexual reproduction
 Explain how karyotypes are made and be able to identify homologous chromosomes in
a human karyotype.
 Differentiate between a male and female karyotype.
HUMAN GENETICS
& MEIOSIS
PHA: Biology 9
Moretti and Dickson
Asexual vs. Sexual Reproduction
Asexual Reproduction



One parent
Parent and offspring are
genetically identical (clones)
Reproduce using MITOSIS
Sexual Reproduction



Two parents
Offspring are genetically
different from parents
Reproduce using MEIOSIS
(makes eggs and sperm)
and FERTILIZATION (egg
and sperm join)
Objectives for Class:
• Describe the difference between asexual and sexual reproduction
Sexual reproduction cycle:
Human body cells contain…

Over 20,000 genes stored on
46 total chromosomes

23 pairs of homologous
chromosomes

22 are same in males in
females (1-22)

The 23rd pair is the sexdetermining chromosomes

Females = X X

Males = X Y
Objectives for Class:
• Explain how karyotypes are made and be able to identify homologous chromosomes in a human karyotype.
• Differentiate between a male and female karyotype.
Karyotyping Activity – Part I
Individual A
Individual A
Circle 3 pairs of homologous chromosomes
Objectives for Class:
• Explain how karyotypes are made and be able to identify homologous chromosomes in a human karyotype.
• Differentiate between a male and female karyotype.
Bio 9B: Tuesday, 3.15.11
Title: Meiosis & Genetic Inheritance – Vocab. Review

Homework:

Read Section 11.4 (pages 275-278). Address the following questions:
 What is the purpose of meiosis?




Do Now:


How does the process accomplish this purpose? What are the major steps
and the final result?
How does the process of meiosis create gametes that are different from each
other? Name two ways.
Why does it matter that a person’s gametes are not all the same?
Take out Karyotype activity from yesterday.
Today’s Objectives:


Differentiate between mitosis and meiosis
Explain how meiosis produces 4 haploid sex cells (gametes) – eggs and sperm
Karyotyping Activity – Part I
Individual A
Individual A
Circle 3 pairs of homologous chromosomes
Objectives for Class:
• Explain how karyotypes are made and be able to identify homologous chromosomes in a human karyotype.
• Differentiate between a male and female karyotype.
Quick Genetics Vocabulary Quiz

Word Bank: Diploid, Haploid, Gametes, Meiosis, Alleles,

Match the above words with the definition. You will not use all of the above words
1.
2.
3.
4.
5.
6.
7.
8.
Chromosome, Gene, Homologous Chromosomes
Egg or sperm cells used in sexual reproduction are called____?
A cell that contains TWO COPIES of every chromosome (in homologous
pairs) is called ___?
A pair of chromosomes that contain the same genes but not necessarily
the same alleles are called ______?
The process that separates homologous chromosomes into different
haploid cells is called ____.
Different versions of a gene are called _____?
A cell that contains ONE COPY of every chromosome is called ___?
Are eggs and sperm are haploid or diploid?
A section of DNA that holds instructions for making one protein is called
a _____?
Major Genetics Terms
 Gene:
A section of DNA that holds instructions for making
one protein
Ex: gene for hemoglobin protein
•
 Alleles:
Different versions of a gene
Ex: normal hemoglobin allele vs.
mutated hemoglobin allele
•
 Chromosome:
•
A long strand of DNA, coiled and
wrapped up, that contains many
genes
 Homologous
•
Chromosomes:
A pair of chromosomes that contain the same genes but not
necessarily the same alleles
Major Genetics Terms

Diploid: A cell that contains TWO COPIES of every
chromosome (in homologous pairs)


Haploid: A cell that contains ONE COPY of every
chromosome


Gametes are haploid.
Gametes: Egg or sperm cells, used in sexual
reproduction.


All human body cells except gametes are diploid.
Contain HALF the number of chromosomes as all other
body cells (they are haploid!)
Meiosis: The process of making gametes.
1 Diploid cell  4 Haploid cells
 Separates homologous chromosomes into different
cells

Sexual reproduction cycle:
Studying Diagrams: (30 min)

In your notebooks, respond to these questions:
 What
is the difference between Metaphase in Mitosis
and Metaphase I in Meiosis? Why are the
chromosomes aligned differently in both of these
stages?
 Are the cells diploid in Mitosis during this phase? In
Meiosis? Why?
 What do you notice about the homologous
chromosomes in Metaphase II of Meiosis? Why are
the chromosomes aligned the way they are?
 Are the cells in Metaphase II diploid or haploid? Why?
Start: Diploid Cell
Start: Diploid Cell
(46 Chromosomes
in Humans)
(46 Chromosomes
in Humans)
Metaphase I:
chromosomes
line up with
homologous
pairs
Metaphase
II: like mitosis
End: 4
Haploid Cells
(23 Chromosomes
in Humans)
Cells different from
starting cell (half
the # of
chromosomes)
Metaphase:
chromosomes
line up single file
End: 2
Diploid Cells
(46
Chromosomes
in Humans)
Cells same as
starting cell
Bio 9B: Wednesday, 3.16.11
Title: Meiosis Simulations

Homework:
 Complete

the Meiosis Pipecleaner Simulation Questions
Do Now:
 What
are the differences between Meiosis and Mitosis?
What are the similarities?

Today’s Objectives:



Differentiate between mitosis and meiosis
Explain how meiosis produces 4 haploid sex cells (gametes) – eggs
and sperm
Describe the two ways meiosis creates genetic diversity between
gametes
Start: Diploid Cell
Start: Diploid Cell
(46 Chromosomes
in Humans)
(46 Chromosomes
in Humans)
Metaphase I:
chromosomes
line up with
homologous
pairs
Metaphase
II: like mitosis
End: 4
Haploid Cells
(23 Chromosomes
in Humans)
Cells different from
starting cell (half
the # of
chromosomes)
Metaphase:
chromosomes
line up single file
End: 2
Diploid Cells
(46
Chromosomes
in Humans)
Cells same as
starting cell
Meiosis Simulation w/ Pipecleaners

Overview:


You will use pipecleaner “chromosomes” to simulate the
process of meiosis.
Objectives:
By the end of this simulation activity, you should be able
to…
 Draw and describe the important steps of meiosis
 Explain how the process of meiosis creates gametes with
half the number of chromosomes as the original cell
 Explain how meiosis generates genetic diversity between
gametes

Bio 9B: Thursday, 3.17.11
Title: Meiosis Simulations

Homework:


Do Now:


Complete the Meiosis Pipecleaner Simulation Questions
What is the difference between Metaphase I in Meiosis and
Metaphase in Mitosis? What impact does this have on how
chromosomes divide?
Today’s Objectives:




Differentiate between mitosis and meiosis
Explain how meiosis produces 4 haploid sex cells (gametes) – eggs and
sperm
Describe the two ways meiosis creates genetic diversity between gametes
Describe the two ways meiosis creates genetic diversity between gametes
Start: Diploid Cell
Start: Diploid Cell
(46 Chromosomes
in Humans)
(46 Chromosomes
in Humans)
Metaphase I:
chromosomes
line up with
homologous
pairs
Metaphase
II: like mitosis
End: 4
Haploid Cells
(23 Chromosomes
in Humans)
Cells different from
starting cell (half
the # of
chromosomes)
Metaphase:
chromosomes
line up single file
End: 2
Diploid Cells
(46
Chromosomes
in Humans)
Cells same as
starting cell
Complete Meiosis Simulation w/ Pipecleaners

Overview:


You will use pipecleaner “chromosomes” to simulate the
process of meiosis.
Objectives:
By the end of this simulation activity, you should be able
to…
 Draw and describe the important steps of meiosis
 Explain how the process of meiosis creates gametes with
half the number of chromosomes as the original cell
 Explain how meiosis generates genetic diversity between
gametes

Summary of Meiosis


DNA is replicated once
Chromosomes are divided
twice:
 Meiosis I: Homologous
chromosomes separate




Forms 2 haploid cells
Chromosomes still have sister
chromatids
Meiosis II: Sister chromatids
separate
Final result:
4 haploid gametes with HALF
the number of chromosomes as
the original cell
Gametes
Objectives for Class:
• Explain how meiosis produces 4 haploid sex cells (gametes) – eggs and sperm
Sexual reproduction cycle:
Meiosis generates genetic diversity
between gametes: Two Ways
1. Independent
alignment of
homologous
pairs during
Metaphase I.
 A cell with 2
homologous pairs
yields 4 possible
gametes.
 How many are
possible with 23
homologous pairs?
Meiosis generates genetic diversity
between gametes: Two Ways
2. Crossing over during Prophase I.



One sister chromatid trades a section of DNA with its homologous partner.
Creates new combinations of alleles on chromosomes.
Can happen at multiple places along the chromosome, allowing for a nearly
infinite number of different gametes.
Errors in Meiosis Preview
Nondisjunction Videos
Bio 9B: Monday, 3.21.11
Title: Karyotyping Part II

Homework:
Complete the Karyotyping Part II Analysis Questions
 Submit Modeling Meiosis by passing it to the left


Do Now:


What are the two ways Meiosis creates genetic variation? (hint:
look to your notes from our last class period)
Today’s Objectives:



Differentiate between mitosis and meiosis
Explain how meiosis produces 4 haploid sex cells (gametes) – eggs and
sperm
Identify genetic disorders that result from mistakes during Meiosis
Karyotyping Activity – Part II
As you have learned, a karyotype is an enlarged photograph of a person’s chromosomes arranged so
that the homologous chromosomes are next to each other. As we have also discussed, meiosis is the process
that separates these homologous chromosomes into different sex cells called gametes. When meiosis works
properly, each gamete will receive one copy of each type of chromosome (one chromosome 1, one
chromosome 2, etc.). However, sometimes an error in meiosis occurs and gametes receive abnormal
numbers of chromosomes. When these gametes (eggs or sperm) join with the gamete from another
individual during fertilization, the result is a person with an abnormal numbers of chromosomes.
In this activity, you will examine the karyotypes for a variety of different people to determine if the
individual has the expected number of 46 total chromosomes. Analyze each karyotype by answering the
questions for each one. If you determine that the individual has an abnormal number of chromosomes,
determine the type of chromosome disorder the person has and describe it in the space provided.
Objectives for Class:
• Explain how karyotypes are made and be able to identify homologous chromosomes in a human karyotype.
• Identify genetic disorders that result from mistakes during Meiosis
Karyotyping Activity – Part II Review
Nondisjunction Videos