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EQ: Where does an organism gets its unique characteristics?
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Fri. 3/1/19 NB PG. 2
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1. Turn to page 2 in your
notebook
2. Make a quick list of
the characteristics you
have of the choices on
the left.
TREE
OBJECTIVE:
Find the most and least common combination of three traits in our class!
PTC paper: In 1931, a chemist named Arthur Fox was pouring some powdered PTC into a bottle. When some of the powder accidentally blew into the air, a colleague standing nearby complained that the dust tasted bitter. Fox tasted nothing at all.
▪ Although PTC is not found in nature, the ability to taste it correlates strongly with the ability to taste other bitter substances that do occur naturally, many of which are toxins.
▪ Plants produce a variety of toxic compounds in order to protect themselves from being eaten. The ability to discern bitter tastes evolved as a mechanism to prevent early humans from eating poisonous plants. Humans have about 30 genes that code for bitter taste receptors. Each receptor can interact with several compounds, allowing people to taste a wide variety of bitter substances.
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1. In your notebook:
2. Ask your partner to identify what characteristic they observe on you.
3. PTC paper will be given to you when you are done with the table and it is written in your notebook.
4. CUT OUT your leaf and write down your initials.
BOYS use dark green leaves and GIRLS use light green leaves.
5. Walk over to the tree and follow the branches. SEE INSTRUCTOR.
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Trait YES NO
PTC PAPER
Attached earlobes
Tongue roller
Textbook page 263-266:
▪ Genetics
▪ Fertilization
▪ True-breeding
▪ Trait
▪ Hybrid
▪ Gene
▪ Allele
▪ Segregation
▪ Gamete
DUE BY Tomorow
Textbook page 267-269
•Probability
•Punnett square
•Homozygous
•Heterozygous
•Phenotype
•Genotype
For the following terms:- write & underline the term-define it-draw and color a picture that represents the term and definition, combined
7
EQ: How are different
forms of a gene
distributed to
offspring?
NB pg. 5
Title: "Mendel"
1. What did Gregor
Mendel discover in
the results of his first
experiment?
2. What did Mendel
discover in his
second experiment?
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GREGOR MENDEL
Gregor Mendel as a Austrian monk who was born in 1822. He spent a great deal of time in the monastery garden where he was able to carry out experiments into inheritance. He chose to work with peas, which are small and easy to grow, and produce large number of offspring.
▪ Peas are a “model system.”
▪ •Started with “true breeding” plants
▪ •Trait: specific characteristic (e.g., seed color, plant height) of an individual
▪ •Hybrid: created from cross of true-breeding individuals
Mendel’s different groups of true-breeding plants would produce the same set of traits in each generation.
To figure out how traits were inherited from one generation to the next, Mendel crossed individuals from his true-breeding strains to produce hybrids.
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▪ Mendel did not have our modern understanding of genes and alleles, he did understand that male parts of a flower produce male sex cells (sperm) and that female parts of a flower produce female sex cells (eggs), and that these cells join in the process fertilization.
▪ While offspring are produced from only one parent, each offspring forms from the fusion of male and female cells.
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3 of 9 READ
▪ Mendel removed reproductive structuresfrom pea flowers so that only one set remained.
▪ Mendel was looking at seven characteristics in pea plants. His goal was to look for patterns in the traits across generations.
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▪ Genes: passed from one generation to the next; determine an individual’s characteristics
▪ Alleles: the different forms of a gene
With your partner, complete the following sentences:
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Characteristics such as seed color
are determined by ___________ .
Yellow and green seed colors are
determined by _______ .
The allele for yellow seeds is _______
to the allele for green.
WORD BANK:
Alleles
Dominant
Genes
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PRINCIPLE OF DOMINANCE
▪ Some alleles are dominant, some recessive.
▪ An organism with at least one dominant allele will exhibit that trait.
▪ An organism with a recessive allele will exhibit the trait only in the absence of a dominant allele.
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6 of 9
MENDEL’S F1 CROSSES
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When Mendel
crossed plants with
contrasting traits, the
hybrid offspring
showed traits of
only one parent.
7 of 9 READ
▪ Segregation: separation of alleles during gamete formation
Why didn’t the allele for yellow color show in the F1 generation?
Was the recessive allele for yellow color lost in the F1 generation? How do you know?
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THE FORMATION OF GAMETES
▪ during formation of gametes, or sex cells, alleles segregate from each other so that each gamete carries only a single copy of (one allele for) each gene.
Where are the eggs and sperm?
Where does fertilization occur?
SUMMARY: 15
9 of 9
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NB Pg. 7
EQ: How can we use
probability to predict
traits?
Video Questions:
1. How many chromosomes
do we receive from EACH
parent?
2. What are Punnett squares
used for?
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▪ In your notebook write the table below:
1. You and your partner will take turns flipping a coin. 10 times each.
2. Tally mark (/) the number of times out of ten, that the coin lands on either heads up or tails up on your table/ counter.
Heads Tails
Me
Partner
2 of 8 READ
PROBABILITY AND HEREDITY▪Probability: the likelihood an event will
occur. If you flip a coin, what is the
▪ probability of either outcome: ________
▪ Three coin tosses? _____________
▪ Each flip is an independent event.
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3 of 8
GENOTYPE AND PHENOTYPE- DRAW A T-CHART
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Two organisms may share the same __________
but have different ______________
4 of 8
HETEROZYGOUS AND HOMOZYGOUS
▪ Homozygous: has two identical alleles for a gene
▪ Heterozygous: has two different alleles for a gene
▪ Which are:
Homozygous? _______ heterozygous? ______
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1 2 3 4
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6 of 8 READ
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The Two-
Factor Cross
7 of 8 READ
SUMMARY OF MENDEL’S PRINCIPLES▪ Inheritance is determined by units called __________ ,
which are passed from parents to offspring.
▪Where more than one form of a gene for a single trait exists, some alleles may be ______________ and others ______________ .
▪Each adult has two copies of each gene—one from each parent. These genes ____________ from each other when gametes are formed.
▪Alleles for different genes usually segregate ____________ of each other.
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WORD BANK:
Dominant
Genes
Recessive
Independently
segregate
8 of 8
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1. You will work with your
partner next to you.
2. Partner 1 will do 1 and
Partner 2 will do 2 and 4
3. CHECK each others
answers.
4. Be prepared to share
out.
If you do not finish
Spongebob WS, it will be
HW
EQ: What are some exceptions to Mendel's principles?
Feather color in parakeets is controlled by multiple genes
25
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▪Describe some of the exceptions to Mendel’s principles.
▪Explain the environment’s role in the way genes determine traits.
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▪ 1. What is a polygenic trait? Give an example?
▪ 2. Something new I learned....
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INCOMPLETE DOMINANCE
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▪Some alleles are neither dominant nor recessive.
▪Incomplete dominance: One allele is not completely dominant over another.
4 of 8
▪The phenotypes for both alleles are clearly expressed.
▪Examples: chicken feather color, human protein controlling blood cholesterol levels
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MULTIPLE ALLELES
▪Many genes exist in more than two forms.
▪Examples: human blood types, fur color in rabbits
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POLYGENIC TRAITS
▪Many traits are produced by the interaction of several genes.
▪Examples: eye color in fruit flies, coat color in dogs, skin color in humans.
▪Traits typically show a wide variety of phenotypes.
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▪Environmental conditions can affect gene expression and influence genetically determined traits.
▪The __________ of an organism is only partly
determined by its ___________________
SUMMARY:32
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Warm-up Activity: (pick up cards in baggie)
1. With your partner, match up the different types of patterns of inheritance cards with the description and example.
2. When you are done, raise your hand.
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1 of 7 no notes
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Differentiate Differentiate between monohybrid and dihybrid crosses
ANALYZE Analyze dihybrid cross using two traits.
Relate Relate to the principle of independent assortment
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1.What is Mendel's
law of segregation
mean?
2. What does
the law
of independent
assortment mean?
DIHYBRID CROSS
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Directions:
1. Pair up!
2. Decide who is Partner 1 and partner 2.
3. Individually complete #1-3
4. Complete #4 together
DIHYBRID CROSS
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Directions:
Now, continue to work on the rest of the problems.
I will check in with you periodically.
Did we accomplish the following:
Relate to the principle of independent assortment
Construct a dihybrid cross using two traits
Differentiate between monohybrid and dihybrid
crosses
Homework: Finish handout by Monday.
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EQ: Why do blood
types matter?
Video Questions:
1. How do antigens
communicate with our
cells?
2. If you inherit an "O" and
an "A" allele, what will
happen?
3. For blood transfusions,
finding the correct blood
type is a matter of life or
death. Explain why.
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HW: READ TXBK pg. 344-345
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Blood
Type
phenotype
Genotype
Can
donate
blood to:
Can
receive
blood
from:
1. Add the table below into your notebook
2. Update your NB with title" Codominance-Blood"
3. As you watch the video, fill in the table.
4. Be ready to answer.
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Purpose: To create a
dragon baby using
genetics!
1. You will need to work
with your elbow
partner!
2. Write your name on
your packet. EVERYONE
will have their own.
3. Watch intro video.
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▪ Write down mom and dad alleles
▪ Determine baby alleles by flipping the popsicle stick.
REMINDER: You cannot take the popsicle sticks home, therefore fill out yur data tables with the designated alleles and do the TRAIT description AT HOME!!!
Tomorrow, you will have an additional day to finish and turn in the packet seperatly from the questions in your notebook
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▪EQ: What patterns of inheritance do human traits follow?
1. Why is it called a sex-linked trait?
2. Why are there more sex-linked traits on the x chromosome?
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KARYOTYPES
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▪A genome is the full set of genetic information that an organism carries in its DNA. The analysis of any genome starts with chromosomes.
▪A karyotype shows the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size.
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SEX CHROMOSOMES
▪ Two of the chromosomes in the human genome are sex chromosomes.
▪ § Females: two X chromosomes
▪ § Males: one X chromosome; one Y chromosome
▪ More than 1400 genes are found on the human X chromosome.
▪ The human Y chromosome contains only about 158 genes.
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AUTOSOMAL CHROMOSOMES
▪The other 22 pairs of non-sex chromosomes are called autosomal chromosomes or autosomes.
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CODOMINANT AND MULTIPLE ALLELES
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The alleles for
many human
genes display
codominant
inheritance.
Ex: Blood Types
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▪The X and Y chromosomes determine sex.
▪The genes located on them show sex linkage.
▪EX: Colorblindness is a sex-linked trait
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Do not say what you see
6 of 10
X-CHROMOSOME INACTIVATION
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• Female calico cats are tri-colored.
• The color of spots on a Calico cat fur is controlled by a gene
on the X chromosome.
• How many different colors of spots can a male cat
have?
Most genes in one of the X chromosomes are switched off,
forming a region known as a Barr body.
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HUMAN PEDIGREES
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HUMAN PEDIGREES
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A pedigree chart
shows the
relationships
within a family.
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HUMAN PEDIGREES
▪ The information from pedigree analysis makes it possible to determine the nature of genes and alleles associated with inherited human traits.
▪ SUMMARY:
Write a family pedigree of your own using ONE TRAIT. You may have to research whether the trait is dominant or recessive. It needs to have at least 2 generations.
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WARM-UP: Pick up a whiteboard, list the different ways mutations can occur.
Recall our unit about DNA and mutations as well as our Dragon Genetics
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MEIOSIS AND HUMAN GENETIC DISORDERS
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OBJECTIVES:
1. Describe the events that
occur during each phase of meiosis.
2. Identify the differences
between meiosis and
mitosis.
3. Explain the effects of errors in meiosis.
4. Describe how
small changes in DNA affect human traits
▪EQ: What occurs in meiosis and what are the effects of errors in meiosis?
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CHROMOSOME NUMBER
▪ Homologous: chromosomes with the same genes, one originally from each of the organism’s parents
▪Diploid: containing both sets of homologous chromosomes; 2N
▪Haploid: containing only a single set of chromosomes; 1N
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1. What is the goal of mitosis?2. What are the phases?
3. What is the end product?
MEIOSIS
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After the video, we will be able to find out:
1. What is the goal of meiosis?
2. What are the phases?
3. What is the end product?
64TXTBK pgs. 275-278
CHROMOSOMAL DISORDERS: NONDISJUNCTION▪Nondisjunction: when
homologous chromosomes do not separate as they should
▪Gametes with an abnormal number of chromosomes may result.
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DOWN SYNDROME
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The most common form of trisomy,
involving three copies of chromosome
21, is Down syndrome.
- if two copies of an autosomal
chromosome fail to separate during
meiosis, an individual may be born with
three copies of that chromosome
▪Nondisjunction of the X chromosomes can lead to a disorder known as Turner’s syndrome.
▪In males, nondisjunction may cause Klinefelter’s syndrome.
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FROM MOLECULE TO PHENOTYPE
Changes in the DNA sequence of a gene can change proteins:
▪ Altering amino acid sequences
▪ Affecting the phenotype
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How do small changes in DNA molecules affect human traits?
One disorder caused by individual genes is sickle cell disease. sickle-shaped cells are more rigid than
normal red blood cells, and therefore they tend to get stuck in the capillaries
GENETIC ADVANTAGESWhy are these alleles still around if they can be fatal for those who
carry them?
▪ Some alleles that cause disease may also have benefits.▪ Carrying one copy of the sickle cell provides
protection from malaria.▪ Carrying one copy of the Cystic Fibrosis allele provides
protection from typhoid bacterium
Summary:
Extra Credit Opportunity:
CER of this article. It is available on the school website. 69