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Cells
ORGANIZING GENETIC MATERIAL
****Revision for next year: Divide into two lessons:
1) nuclear organization of genes vs. chromosomes vs. chromatids
2) chromosome analysis for autosomes, sex chromosomes, homologous pairs, alleles
Aims:
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Describe structure of nucleus
Explain the relationship between chromatin, chromosomes, genes and DNA
Analyze patterns in chromosome arrangement
Agenda:
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Debrief diagram
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Demos
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Poll
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Genie in a bottle
Debrief
Extension
Engage Show messy vs. organized backpack. What are the advantages to an organized backpack? Discuss the
battle for students to keep their information organized. Then tell students that a cell has an even tougher job in
organizing its information – DNA. Show a piece of string that is 2 meters (6 feet) long and represents the length of DNA
in each of your cells (add that it’s made of 6 billion base pairs and if the DNA in all trillion of your cells were stretched
out, it would stretch from earth to sun and ¾ way back). How does that much DNA fit into a cell and how does all
that information stay organized? Elicit ideas and restate the essential question of this lesson: How does the nucleus
organize genetic material and win the battle against chaos?
Explain
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Slide show of various diagrams of genetic organization to distinguish genes, chromosomes, chromatids
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Debrief Do Now under doc cam
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How is this diagram a simplification of the nucleus?
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What do the arrows/lines mean this time?
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How did the chromosome double to make two chromatids?
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Boxes within boxes to illustrate relative sizes
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Demo 1: Show spool of thread for DNA coiling around proteins. How does this represent genetic material?
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Demo 2: Bioflix video for chromatin, histones, DNA. How is chromatin different from chromosomes?
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Demo 3: Uncoil ball of yarn and separate out into individual pieces to further distinguish chromatin
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Poll to check for understanding
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Students watch chromosome animation when done
Explore
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Give students baggie of chromosomes
How do these components represent a human cell?
Elicit that bag represents cell, board nucleus and jumble of magnets is chromosomes
Students condense chromatin into chromosomes and organize them
Students write patterns observed and method of organization
Explain
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Elicit that chromosomes occur in pairs known as homologous chromosomes
Elicit that humans have 23 pairs for a total of 46
Show slide of homologous pair to elicit that there are two genes for each trait – known as alleles
Explain terms for autosomes, sex chromosomes
Use karyotypes of pig, dog, mouse to practice identifying autosomes and sex chromosomes
Extend
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Diagrams (if needed)
Karyotype
Open-ended
Exit Slip: MC questions
Homework: Annotation on cell reproduction (8.1-8.3)
ORGANIZING GENETIC MATERIAL
Cells
Do Now
1.
Study the diagrams below and annotate with additional information.
Gene
2. Use the diagrams above to determine whether the following statements are true or false.
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Chromosomes are found in the nucleus of a cell.
A cell contains more genes than chromosomes.
Genes are made of chromosomes which are made of DNA.
A gene contains the instructions for building a protein.
Chromosomes are copies of chromatids.
For every centromere there are two chromatids.
3. What questions do you have about this diagram and the information it shows?
Cells
ORGANIZING GENETIC MATERIAL
Chromosome Chaos
1. How do the bag, whiteboard and the magnets represent a human cell?
2. Work with your partner to organize the chromosomes. Describe any patterns you observe.
3. Explain your method of organization and be prepared to share with the class.
Extension
1. Show how genetic information is organized by putting each term in the correct circle: gene, cell,
chromatin, nucleus, chromosome, nucleotide, DNA.
2. Label the diagram using these possible terms: bases, nucleus, gene, chromosome, DNA, cell
Cells
ORGANIZING GENETIC MATERIAL
3. Each diagram below is a karyotype, a photo of the contents of the nucleus of a cell. In each
karyotype, CIRCLE two alleles for a particular trait, BOX one homologous pair of autosomes, draw an
ARROW to the sex chromosomes, determine if the organism is HUMAN and MALE or FEMALE and provide
EVIDENCE.
4.
Explain the relationship between genes, chromatin, chromosomes and DNA.
5. How it is possible for 2 feet of DNA to fit inside each of your cells.
6. Predict how your cell would be affected if the proteins in your nucleus denatured.
7. A scientific study found that in human blood cells, the length of telomeres ranges from 8,000 base
pairs at birth to 3,000 base pairs as people age and as low as 1,500 in elderly people. Another
recent study divided people into two groups based on telomere lengths and found that the
people with longer telomeres lived five years longer than those with shorter telomeres. A related
study found that in people older than 60, those with shorter telomeres were three times more likely
to die from heart disease and eight times more likely to die from infectious disease. Draw two
conclusions based on these studies and provide evidence.
Cells
Exit Slip
ORGANIZING GENETIC MATERIAL
Cells
ORGANIZING GENETIC MATERIAL
Block 1 Agenda
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Joke
Teach allele via Do Now diagram
Model chromosomes with beads or plastic
Review genetic organization with slide show
Extension questions #4-7
Chromosome analysis
Model with boards and magnets a haploid/diploid cell with n=x
Poll
Extension questions
Exit Slip
Block 2/3 Agenda
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Joke
Teach allele via Do Now diagram
Model chromosomes with beads or plastic
Chromosome Chaos
Extension questions #3
Chromosome analysis
Model with boards and magnets a haploid/diploid cell with n=x
Poll
Extension questions
Exit Slip
ORGANIZING GENETIC MATERIAL
Cells
Do Now
1. Label the diagram below and annotate it with inferences.
2. A particularly insightful 11th grade Biology student created the following analogy to explain how
genetic information is organized. Evaluate the strengths and weaknesses of the analogy.
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cell: locker
nucleus: backpack
binder: chromosomes
paper: genes
text: DNA
letters of text: nucleotides
Modeling Homologous Chromosomes
1. Use the materials at your table to model each of the following:
 One homologous pair of chromosomes
 Two sets of alleles on that homologous pair
 Sister chromatids of the homologous pair
 Centromere
2. Explain how your model represents these components, and be prepared to present.
ORGANIZING GENETIC MATERIAL
Cells
Chromosome Analysis
The karyotypes below show the contents of the nucleus of two different cells. Study and annotate the
diagrams below using outside knowledge and inferences.
Extension
1. Determine the haploid number or diploid number for each species in the table below.
Common Name
Genus and Species
Diploid
Number
Buffalo
Bison bison
Cat
Felis catus
Dog
Canis familiaris
78
Goat
Capra hircus
60
Horse
Equus caballus
Human
Homo sapiens
Sheep
Ovis aries
Haploid Chromosome
Number
60
19
32
46
27
2. Identify each cell as a haploid or diploid and gamete or somatic. Then provide evidence.
A.
B.
C.
D.
ORGANIZING GENETIC MATERIAL
Cells
Exit Slip
1. Which of the following CORRECTLY describes how genetic information is organized in the
cell?
A. A protein contains the coded information for building a gene
B. A nucleus contains genes which are made of chromosomes
C. Chromosomes condense into tightly coiled rod-shaped bodies call chromatin.
E. Chromosomes occur in homologous pairs.
F. There are usually three versions or alleles of each gene.
2. Which of the following does NOT describe how genetic information is organized in the cell?
A. A gene contains the coded information for building a protein
B. A nucleus contains chromosomes which are made of genes
C. The sequence of bases in DNA determines the sequence of amino acids in protein
D. DNA is a single-stranded helix containing the bases A, U, C and G
1. A chromosome is best described as a
a. gene that has more than one form.
b. green cell found in many plants.
c. strand of DNA containing genetic information.
d. reproductive cell found in certain kinds of bacteria.
2. What is the relationship between the three structures in the diagram?
a. DNA is produced by protein which is produced in the cell
b. Protein is made of DNA which is produced in the cell
c. DNA contains the instructions for protein production in the cell
d. A cell is composed of only DNA and protein
5. The diagram at the right shows the
process of protein synthesis. Which of the
following is true of this process?
A. Transcription produces DNA
B. Translation occurs in the nucleus
C. RNA is produced at the ribosome
D. RNA acts as a messenger for DNA
Cells
ORGANIZING GENETIC MATERIAL
Notes
Genetic information is found in the cell’s ______________ which is enclosed by a _______________
__________________ full of _____________ or openings.
Inside the nucleus is _________________, a tangled mass of ______ and proteins.
The chromatin can coil up into distinct, rod-shaped bodies called _______________________.
These are made of smaller units called ________________.
Each gene is made of hundreds or thousands of _______________________
The sequence of nucleotide bases in a gene determines the instructions for building a _______________.
_____________________ chromosomes are pairs of chromosomes with similar ________, ________ and
_____________ information. Organisms usually have ________ versions of each gene, one located on each
homologous chromosome.
Humans have ________ pairs of chromosomes for a total of ____. In humans, chromosome pairs #1-22 are
_____________________ while pair #23 is the _____ chromosomes. Males have ________ and females have
________.
Cells
ORGANIZING GENETIC MATERIAL
Genie in a Bottle
Directions: Each pipe cleaner piece in your bag represents a chromosome. Remove the chromosomes
from the baggie. Then sort or arrange them in a way that makes sense to you. Check with your teacher
before answering the questions below.
1. What does the baggie represent? Hint: where chromosomes would be found…
2. Describe how you sorted your chromosomes.
3. Explain why you sorted your chromosomes the way you did.