Download What is DNA? - Livingstone High School

Genetics
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Heredity: The process in which
characteristics or traits pass from parents
to offspring.
Think, Pair, Share some characteristics
that you have in common with either
parent
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Tracking Down Traits
Learning Experience 1
1. Review Procedures
2. Rule: No person may sign the list more
than twice.
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What do you know about
DNA?
Where have you
heard the term?
What was the context
or situation?
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What is DNA?
• The genetic material that
carries information about an
organism passed from
parent to offspring
• A complete set of
instructions necessary to
make and maintain the
human body.
• A Blueprint of the human
body
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Why is DNA Interesting?
• DNA is a nonliving molecule.
• There are 6 feet of it in every cell.
• The human body can have as many as ten thousand
trillion cells, and almost every one of them has 6 feet
of densely compacted DNA.
• DNA is unique for every individual
• DNA controls all the activities in the cell from the
nucleus.
• DNA is a nonreactive chemically inert molecule
Why is DNA interesting?
What is DNA?
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DNA and Crime Solving
• Because DNA is a nonliving, nonreactive
chemical molecule…
• It can be recovered from mummies over
2000 years old.
• Long-dried blood in murder investigations
• Ancient bones
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Where is
DNA?
Cell
Nucleus – the
Control Center
Chromosomes
Chromosomes are
made of DNA
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Where is DNA?
Draw and label the
location of DNA in
the cell
Draw and label the
relationship between
DNA and chromosomes.
Make the Chromosome Model
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Each human Cell have 23 pairs of Chromosomes
Mother
Father
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Chromosomes are made of genes
A gene is a section of DNA that
controls a trait ( ex. tall /short) that an
organism inherits
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A Model of a Chromosome
Gene
•Chromosomes are made up genes.
•A gene is a section of DNA (section
of a chromosome) that controls a
trait that an organism inherits.
•If the string of shapes represents a
chromosome – what does each
individual shape represent?
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Gene for the Trait
Brown Eye color
Gene for Tall Height
Gene for Brown
Hair color
Gene for Attached vs
Unattached Earlobes
Gene for the
Shape of our
Fingers
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Humans Chromosomes
What are the dark
lines?
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How important are chromosomes?
• Humans need all 46
chromosomes for normal
development and function.
• Humans that are missing even
one of the 46 chromosomes do
not survive.
• Humans with more than two
copies of a chromosome will
not develop properly.
Downs Syndrome is caused
by an extra chromosome.
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Compared to a real human chromosome,
what are the limitations of the model?
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Active Learning
• Write a riddle about one or two of the
following terms:
– DNA, Genes, traits, chromosomes
• Write a Haiku about the importance of
DNA
(5-7-5 syllable pattern)
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One set of chromosomes come from the
mother and one set of chromosomes come
from the father.
The entire chain of shapes represent a
chromosome - the individual shapes
represent genes.
The offspring inherits a pair of genes for
each trait. When the genes are identical
the offspring is called homozgous or
purebred for that trait. When the genes
are different, the offspring is called
heterozygous or hybrid for that trait.
Which gene pairs would make a
homozygous offspring ? (similarities)
Which genes pairs would make a
heterozygous? (Differences)
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What are the limitations of our model
compared to the scientific model on the right?
Pair of genes
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Gene for the trait
Brown Eye color
Gene for Brown Eye
color
Gene for Tall Height
Gene for Brown
Hair color
Gene for the
Shape of your
Fingers
Gene for Attached
Earlobes
Gene for Tall Height
What is
the mother’s
phenotype?
Gene for Black
Hair color
Gene for the
Shape of your
Fingers
Gene for Unattached
Earlobes
Phenotype-The physical characteristics/traits you can observe
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Gene for the trait
Brown Eye color
Gene for Tall Height
Gene for Brown
Hair color
Gene for the
Shape of your
Fingers
Gene for Attached
Earlobes
Gene for Brown Eye
color
Gene for Tall Height
Gene for Black
Hair color
Gene for the
Shape of your
Fingers
Gene for Unattached
Earlobes
Genotype- The two genes that determine an organism's (offsprings) traits
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Do Your Earlobes Hang
Down?
Learning Experience 2
1.
2.
3.
After each trait is described – mark a
check under Yes or No in the Me column.
Collect data for each trait from the entire
class.
Graph class data for each trait
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Vocabulary
• Genotype – the two • Phenotype – The
genes that determine
physical characteristics
an organisms traits
of an organism you
can observe.
• The genotype of a tall
plant that has two
• The phenotype of a tall
genes alleles for
plant is tall, regardless
tallness is TT
of the genes it contains
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Transparent Traits
Learning Experience 3
This activity models the random selection of a egg and a sperm in
producing the genotype and phenotype of offspring.
Please model using the overhead prior to the students conducting the
lab.
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Transparent Traits
Formative Assessment Questions
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What do the colored squares represent?
Why are the genes always removed in pairs?
Where does the organism acquire its genes?
If two colored squares are drawn, what was the organism’s
genotype?
Is the trait dominant or recessive in this organism?
What was the phenotype of this organisms?
If two clear squares were drawn, what was the organism’s
genotype?
If one clear and one colored square are drawn, what was the
organism’s genotype?
Is the trait dominant or recessive in this organism?
What was the phenotype of this organism?
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Based on what you know about genetics thus
far…
What are the limitations of the model?
•Each square represents one gene on one
of the 23 chromosomes.
•Each gene is not selected individually –
they come in packets called ____?
•Human traits like eye color and hair color
have multiple alleles – they are the results
of one gene from the mother and one gene
from the dad.
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Putting it All Together
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Homozygous
Heterozygous
Phenotype
Genotype
Dominant
Recessive
• Dragon Genetics
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Processing
Using the dragon simulation as
an example:
•
•
•
What was changed in order to
change the appearance of the
dragon?
Therefore, a change in the ____
results in a change in the _____.
Do you have to change the genes
on both chromosomes to change
the phenotype? Explain
•
How is the phenotype affected by
the genes being homozygous or
heterozygous?
•
How many different dragon
combinations are possible?
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Mastering Terms
•
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Homozygous
Heterozygous
Phenotype
Genotype
Dominant
Recessive
• How can students
demonstrate their
understanding of
these terms?
Term
Def. in own
words
Picture
Example
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Gregor Mendel
Father of Genetics
• The Story of Gregor
Mendel
• Mendel’s
Experiments:
http://www.cccoe.net/
genetics/mendel.html
• Dominant and
Recessive Traits
http://www.cccoe.net/
genetics/dom_rec.htm
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Activities:
• Interactive Guide to
Mendel’s Experiments
(7th)
• Some Traits are
DominantAnimation/Activity
• http://www.dnaftb.org/
dnaftb/4/concept/
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Write a radio commerical to advertise a visit to your school by
Gregor Mendel. The advertisement should include:
•Why his research impacts what we know about genetics.
•Something that would spark the interest of the students to
come to the presentation.
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Genes in Action
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The Punnet Square
• Use To Teach the Punnet Square: Mendel’s Punnet
Square: http://www.cccoe.net/genetics/punnett.html
• Activity: Living Punnet Square
Example: 2. Two heterozygous for fingers Martians marry and have
four kids. How many of their kids will have three fingers? How many
will have two? Build the living Punnett square and when you’re
ready, call for the teacher.
• Punnet Squares and Dominant and Reccessive Genes
http://www.accessexcellence.org/RC/VL/GG/recessive.html
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Genetic Crosses and Pedigrees
• Biologica: Web Lab, Mendel’s Peas
http://biologica.concord.org/webtest1/web_la
bs_mendels_peas.htm
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Vocabulary
• Natural occurrence is Natural Selection
• Natural selection is the process by
which certain heritable traits—those
that make it more likely for an
organism to survive and successfully
reproduce —become more common
in a population over successive
generations.
• Reflect back on
Cody and Codette’s
offspring.
• Which organisms
would live to survive
and pass on their
genes in this
environment?
• Which would not?
• Which organisms
would be “naturally
selected” to survive
and which would
not?
Cody and Codette
• Reflect back on Cody and Codette’s
offspring. After the entire class has
completed their organism and placed them
into an environment.
• Which organisms would live to survive and
pass on their genes?
• Which would not?
Vocabulary
• Selective breeding:
• The method of breeding certain organisms
together that have desirable traits.
• The process of manipulating the
phenotype of the offspring.
Example of Selective Breeding
Hardy – can thrive in hot
climates, the beef is not as
good
Tender, tasty beef
Does not thrive in hot
climates
Heat resistant cattle with tender beef
Selective Breeding - Ancestry
American Bulldog
Bull Mastiff
Staffordshire Bull Terrier
American Pit Bull Terrier
Selective Breeding
Try it Out!
• Dog Breeding
Ethics
• Think Time
Discuss some possible positive outcomes of :
•Selective Breeding
•Cloning
•Genetic Engineering
Discuss some possible negative outcomes of:
•Selective Breeding
•Cloning
•Genetic Engineering
Putting It All Together
• Sponge Bob
• Make an Acrostic from the word “Heredity”
• Create analogies using the following pairs
of words:
– Homozygous/heterozygous
– Phenotype/genotype
– Dominant/recessive
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Sexual Reproduction in Action
• Activity: Gene (Wo)Man
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