Download Misconceptions, misunderstandings and questions students

Dr. Forrest Spencer
Christine Roberts
Towson High School is a suburban high school located in Towson, Maryland. Biology is
a graduation requirement and is offered to grade 9 and 10 students at a
standard/inclusion, honors, and gifted and talented level. Dr. Spencer and I will deliver
the learning cycle to 2 standard level classes and one standard special education inclusion
class. The students have little exposure to and understanding of biological concepts,
including genetics.
Misconceptions, misunderstandings and questions students have about Meiosis, sexual
reproduction and the inheritance of traits:
Misconceptions
• DNA is not present in all living things
• Meiosis ends in zygote formation
• Only mammalian life cycles contain meiosis, mitosis and fertilization
Misunderstandings and questions:
• Traits result from an organism’s DNA sequence
• What is a flower? What is a fruit?
State standards to be addressed by the intervention:
GOAL 3 : Concepts of Biology
The student will demonstrate the ability to use scientific skills and processes and major
biological concepts to explain the uniqueness and interdependence of living organisms,
their interactions with the environment, and the continuation of life on earth.
Expectation 3: The student will analyze how traits are inherited and passed on from one
generation to another.
Indicator 1: The student will demonstrate that the sorting and recombination of genes
during sexual reproduction has an effect on variation in offspring
Indicator 3: The student will explain how a genetic trait is determined by the code in a
DNA molecule.
In my experience and in discussions with colleagues, there is a consensus that students do
not have an understanding of how traits are inherited and expressed. The topics of
meiosis and protein synthesis are extremely challenging to teach for a variety of reasons.
They are often taught in isolation, with no connection to gene expression. Students have
no frame of reference for the idea that their DNA sequence determines the synthesis of
proteins that determine their traits. Students are exposed to these concepts for the first
time in 9th grade biology. Simply put, in the minds of the students, traits are
characteristics that are inherited from their parents- nothing more. Furthermore, sexual
reproduction is a believed to be a process exhibited in mammals exclusively. The idea
that pollen is the male gamete and that plants reproduce sexually is completely foreign.
Students do not have any concept of what a fruit is or how it comes about.
Partnership Planning
A goal was set to implement the intervention in February of 2008. Once this was
decided, the following events occurred:
September 2007- Dr. Spencer and Christine Roberts communicated via email and made
a plan to meet at Johns Hopkins lab in October. This meeting served to familiarize
Christine with Forrest’s research and the lab facility and also to collaborate and
brainstorm ideas for the intervention.
October 2007- Email correspondence continues. Christine visits Dr. Spencer’s lab. Preplanning for the intervention occurs. The team decides to focus on the disconnect
between meiosis, protein synthesis and the inheritance of traits in the intervention.
December 2007- Communication continues. Dr. Spencer and Christine update each
other on internet research completed and plan a class visit in mid-February.
January 2008- Christine visits Dr. Spencer’s house. Lessons are finalized leading up to,
during and after Dr. Spencer’s visit. It is decided that Dr. Spencer will run a DNA
extraction lab using strawberries with 3 standard level and inclusion Biology classes.
February 14, 2008- Dr. Spencer visits Towson High School and runs the lab. Christine
and Forrest debrief after the lesson and tweak follow-up lessons now that more
misconceptions/misunderstandings have been noted.
March 2008- Christine visits Dr. Spencer’s house and organize and reflect on the
learning cycle. Plans are made for improvements next year and to submit the learning
cycle to GENA.
April 2008- Dr. Spencer and Christine work on the write-up.
May 2008- Dr. Spencer and Christine meet at Towson High School to finish the write-up.
GENA Project Final Report, 2007-2008 Academic Year
Learning Cycle: Genetics in Ninth Grade Biology, Standard and Inclusion Classes
Christine Roberts, Towson High School
Forrest Spencer, Johns Hopkins University School of Medicine
Rationale: To address misconceptions and misunderstandings in genetics.
Our goal was to present a common theme throughout the genetics unit emphasizing that the
sequence of DNA determines an organism’s traits. The following is a chronology of several
strategies used to clearly delineate and reinforce this concept. Most of these ideas were not
utilized last year during genetics instruction.
(1) Genes – More Than Just Letters
Associated Documents
Our study of protein synthesis ended with this exercise to make a connection between DNA
code, amino acid sequence, and traits. Two versions of the investigation were provided
(1stTraitsLab.pdf and 2ndTraitsLab.pdf), in which the initial gene sequence differed by a
single nucleotide deletion. Students compared results with one another, and observed the
effect of the deletion on protein expression and the associated traits. An evaluation of this
resource is provided as a separate attachment (Evaluation_GenesMoreThan).
(2) Meiosis Anticipation Guide
page 3
The anticipation guide includes a pre + post test, providing information reflecting the
students understanding before and after the meiosis unit.
(3) Meiosis
pages 4-7
The events and vocabulary associated with meiosis were presented in class and homework
reading assignments, with support for note taking (Meiosis Notes, pages 4-5) and an exit
ticket to gauge student understanding (page 6). A Meiosis BCR (page 7) was used to
reinforce the use of terminology and to evaluate comprehension.
(4) Paper model of homologue crossing-over
Our study of meiosis included extra emphasis on variation resulting from crossing over
which altered germ cell DNA content, leading to different combinations of traits in offspring.
Students used large paper models of homologous chromosomes to simulate the steps of
meiosis which resulted in 4 genetically different sperm.
(5) DNA Extraction Lab
pages 8-11
The DNA extraction lab emphasized the generality of sexual reproduction by presenting
mitosis and meiosis in the context of this familiar fruit. It illustrated some simple principles
of biochemical extraction used by research laboratories to study DNA as a physical
substance. It was used as an opportunity to point out how DNA codes for proteins that
determine characteristics of strawberry plants, and strawberry fruits. A 5E lesson plan (page
8), mind jog/exit ticket (page 9), lab instructions (page 10), and analysis questions (page 11)
are included below. A powerpoint presentation used for discussion during the lab is provided
as an accompanying document (Strawberries.ppt). Short Cycle and Genetics Unit
Assessments gave additional evaluation for this investigation.
(5) Kidney Bean Germination Demonstration
1
Kidney beans were germinated in the classroom to reinforce the idea that seeds (new
individuals created by sexual reproduction) contain DNA that can direct the development of
many plant tissues.
(6) Punnett Square Introduction
When introducing Punnett Squares, sperm and egg were drawn to make the connection
between meiosis and the inheritance of traits in humans.
(7) Hemoglobin BCR
page 12
This essay was chosen to reinforce the connection between DNA code, enzyme formation,
enzyme activity, and a human trait.
(8) Concept Map
Concept map template (ppt)
A concept map template was created as a visual aid to help illustrate the journey through
genetics that the students encountered in material stretched over several weeks. It is
structured to highlight the relationships between DNA structure, protein synthesis, cell
division (mitosis and meiosis), and the inheritance of traits. The concept map template lacks
arrows: the ‘roads’ are missing from the concept map to allow the same image to support
emphasis on different connections as appropriate for the day on which it is used.
(9) Evolution
pages 13-16
The evolution unit included an analysis of amino acid sequences to illustrate relatedness
between species. Organisms that share similar traits, share similarity in DNA sequence.
Ideas for Future Additions and Improvements
1) Use Mind jog engagements to not only interest the students but as a way to connect
concepts as the topics move from gene expression through meiosis to inheritance patterns.
We plan to get together this summer to brainstorm over generating a well-planned mind jog
series for this purpose.
2) Have students create and discuss their own concept maps at key points within the Genetics
Unit. Provide them with pictures representing main ideas and let them discuss organization of
them. In support of this idea, see Morse and Jutras, CBE-Life Science Education 7:243-253
(2008).
For example: use images from the Concept Map (8) separated onto laminated cards.
3) Add more examples from different organisms to illustrate how the concepts being
presented combine in ways that are useful in understanding real life situations. Use these to
reinforce vocabulary and concepts.
Examples
Might Mouse, Parts 1 and 2
pages 17-18
CCR5 and AIDS
page 19
2
Name______________________________
Date_______________________________
Period_______
Biology
Page 1
Meiosis Anticipation Guide
Agree
Disagree
1. _____
______
2. _____
______
Agree
Disagree
Sex cells are called gametes
_____
_____
Meiosis is a process that produces
_____
_____
_____
_____
_____
_____
cells with ½ the normal number
of chromosomes
3. _____
______
Body cells are haploid and
sex cells are diploid
4. _____
______
The chromosomes in all body cells
are identical but the chromosomes
in sperm or egg cells differ
5. _____
______
Mitosis provides variety is a species _____
_____
6. _____
______
A zygote is created when gametes
_____
_____
Plants reproduce asexually, therefore _____
_____
unite
7. _____
______
the DNA in strawberries from the
same plant is identical
8. _____
______
Fertilization occurs when
_____
_____
gametes unite
9. _____
______
In humans, 2n= 46
_____
_____
10._____
______
A fruit is created when a
_____
_____
flower is fertilized
3
Class Notes /Textbook Notes
Name:
Class:
Period/Block:
Date:
Meiosis
Topic: Meiosis and Genetic Variation
Genes, Chromosomes and Numbers
DIPLOID cellExample:
HAPLOID cellGAMETEThe gamete is a haploid cell that contains__________ the
number of chromosomes as a body cell. When an
organism reproduces, it passes on ________ the number
of chromosomes.
Example: Human body cell: _______ chromosomes
Human gametes: _______ chromosomes
HOMOLOGOUS chromosomes•
•
•
4
5
Questions/Main Ideas:
Notes:
MEIOSIS•
•
Sperm :
Egg:
ZYGOTESEXUAL REPRODUCTIONStages of Meiosis:
CROSSING OVER-
Genetic Variation:
Nondisjunction:
Summary, Reflection, Analysis
6
Name_________________________________
Date____________________
7
Name_________________________________
Date____________________
EXIT TICKET
1. A body cell of an animal has 20 chromosomes. This animal produces gametes with
_________chromosomes.
A. 20
B. 10
C. 40
2. The gametes are produced by the process of __________________
a. Meiosis
B. Mitosis
C. Protein Synthesis
3. The gametes that are produced ARE NOT identical. Think about the different sperm
created in the demonstration today. How and when does the opportunity for genetic
variety occur?
1.
2.
8
MEIOSIS BCR
Carlos (30 years old) and Michelle (26 years old) are expecting their first child. They come to
you, a genetic counselor, for advice. The are concerned about their child inheriting a
chromosome abnormality, particularly Down Syndrome. From your research, you have obtained
the following data on how the age of the mother and father affect the occurrence of Down
Syndrome.
Write a letter to Carlos and Michelle advising them about the probability that they will have a
child with Down Syndrome. In your response, be sure to
• Describe how gametes are produced during meiosis
• Explain the importance of the number of chromosomes in each gamete under normal
conditions
• Describe the error in meiosis that can lead to Down Syndrome
• Use data from the graphs to inform Carlos and Michelle if they have a high or low chance
of having a child with Down Syndrome
• Include appropriate scientific terminology to support and enhance your answer
9
5 E’s Lesson Plan
Engagement: (Warm-up Questions)
1. Do you think the DNA of different strawberries from the same plant is identical? Why or
why not?
2. Where does fruit come from?
Exploration: Power Point Presentation (included).
The strawberry was chosen for our
investigation because it is familiar to students and is a non-mammalian example of an organism
that contains DNA and reproduces sexually. Students are able to see how strawberries come in
different varieties and have different traits. They are introduced to the life cycle of the
strawberry, some students realizing for the first time what a fruit is, how a fruit develops as a
result of sexual reproduction and how sexual reproduction is shared by many living things.
Explanation: A question and answer discussion with the students follows the PowerPoint to
make connections between what they have already learned about DNA, protein synthesis,
meiosis and sexual reproduction.
Elaboration: Students participate in “Extracting DNA from Strawberries” lab.
(included) By
taking part in this activity, the students are able to make a real world connection that DNA is in
all living things, and that traits - even in strawberries - are determined by the genes which code
for proteins.
Evaluation:
•
•
Lab Analysis questions from the lab to be completed for homework
Exit Ticket: (to be completed prior to leaving class)
o Describe how our investigation of strawberry DNA helped you understand that
DNA, the inheritance of traits and sexual reproduction is not limited to mammals.
Use examples from the PowerPoint and the lab activity in your response.
Students also are assessed by taking an SCA (Short Cycle Assessment) on genetics and also a
Unit Benchmark Exam provided by Baltimore County Public Schools. The students are
ultimately assessed on the state HSA (High School Assessment) in May.
10
Name______________________
Mind JogThink about the following questions. Write your ideas in the space provided.
1. Do you think the DNA in different strawberries from the same plant is identical? Why or why
not?
2. How is a fruit or vegetable created?
Exit Ticket•
List 3 facts you learned about strawberries and DNA today.
•
List one question you still have about strawberries (or other plants) and DNA.
123-
1•
List one reason you enjoyed our guest scientist today and how her visit helped you
understand DNA!
I enjoyed spending class with Dr. Spencer because…
I understand DNA and genetics a little better because…
11
Extracting DNA from Strawberries
You will never be able to eat a strawberry again without thinking of how much DNA is in it!
Background:
Why use strawberries?
Strawberries are soft and easy to crush. Most interestingly, strawberries have eight copies of each
chromosome – that is a lot of DNA in each cell!
You will need, for one extraction:
- a zip lock bag
- 1 strawberry
- 2 teaspoons DNA extraction buffer
- Gauze, cut into squares
- Funnel
- Ice cold ethanol or Isopropyl rubbing alcohol
- Test tube with lid
- Long l stick
The DNA extraction buffer:
Makes 500ml (enough for 50 extractions)
50ml shampoo (or 25ml liquid dish washing detergent)
7.5g kitchen salt (1 teaspoon)
450ml water
What to do:
1. Wash the strawberry and remove the sepals (the green leaves)
2. Place the strawberry in a zip lock plastic bag and crush it with your fist
3. Add 2 teaspoons of the DNA extraction buffer to the bag, zip it up and squeeze it in your
hands for 1 minute
4. Place a funnel in the test tube. Place the strip of gauze in the funnel.
5. Pour the strawberry-shampoo mixture into the gauze. Filter the mixture into the tube
6. Carefully pour ice-cold ethanol into the tube, until it is about half full. The ethanol will form
a layer on top of the filtrate.
7. Keep the tube still at eye level; do not shake it. Watch what happens.
8. Scoop out the DNA with the stick.
9. Spread the DNA out on a black card and leave it to dry, to create a DNA print
HOW DOES IT WORK?
Crushing the strawberries breaks open many of the strawberry cells, where the DNA is. The soap in the
shampoo in the extraction buffer breaks down the membranes of the cells, releasing the DNA. The salt
makes the DNA molecules stick together, and separate from the proteins that are also released from the
cells.
The gauze will retain cell debris and unmashed pieces of fruit. The DNA will pass through the gauze into the
test tube.
DNA is not soluble in alcohol, so it precipitates. What you see are long, rope-like DNA molecules in the
alcohol.
Once the DNA dries, you should be able to see its stringy, spider-web structure
12
Questions
1. What did the DNA look like?
2. DNA is soluble in water, but not in ethanol. What does this fact have to do with our method of
extraction? Explain what happened when the ethanol came in contact with the strawberry extract.
3. A person cannot see a single cotton thread 100 feet away, but if you wound thousands of threads
together into a rope, it would be visible at some distance. How is this statement an analogy to our
DNA extraction?
4. Would the DNA be the same in any cell in the human body?
5. If you wanted to extract DNA from a living person, what cells would you use and why?
FUN FACTS!
There are about 2m of DNA in each of your cells?
If all the DNA in your body was put end to end, it would reach to the sun and back over 600
times?
Human DNA is 98 percent identical to chimpanzee DNA?
My DNA is 99% identical to your DNA…yet we are so different!
WOW!!!
Credits
Extraction method and fun facts from www.iscr.ed.ac.uk/outreach/Extracting%20DNA%20prot.pdf
Questions from http://carnegieinstitution.org/first_light_case/horn/DNA/BERRYteacDNA
13
14
Brief Constructed Response (BCR) Item - Released in 2004
Hemoglobin, a protein found in red blood cells, carries oxygen. Abnormal hemoglobin cannot carry
as much oxygen as normal hemoglobin. The sequences below show sections of the DNA sequence
that produce both the normal and abnormal types of hemoglobin.
Write the messenger RNA sequences that would be produced from the normal and
abnormal DNA sequences shown above.
Using the codon table, write the amino acid sequences produced from the DNA for normal
and abnormal hemoglobin.
Beginning with DNA, describe the process that forms proteins such as hemoglobin.
15
16
17
18
19
Muscular Mighty Mouse: Part 1
The transcription and translation of some genes is limited to specific cell types,
where they are used to generate proteins that give rise to cell type differentiation.
For example, muscle cells transcribe and translate genes that encode muscle
proteins that are required for muscle movement. Fat cells transcribe and translate
genes that encode proteins that create, store, and release fat. That is, proteins are
from (1)
among the molecules that give each cell type its characteristic properties. One
type of property a cell type has is regulated growth to create an organ of a given size. Clearly,
this is important if cells are going to cooperate to make a functioning body where all the parts
form in correct relationships.
In 1997, researchers at Johns Hopkins were curious about a new gene they had identified. They
engineered a mouse without it to see what would happen. At first, they had to study mice that
lacked one copy of the gene: remember, mice are diploid and have two copies of every gene.
Their ‘knockout’ (absent) allele was present in one copy, and the normal gene was present in one
copy. They saw nothing unusual. But, they wondered if their knockout allele was recessive. They
generated male and female mice each containing one copy of the mutant allele, and crossed them
together.
ÆFill in the Punnett Square below to explain what happened in this cross. Designate ‘gene+’ as
the normal allele that makes a gene product, and ‘gene-’ as the allele that does not make
anything.
Dad’s alleles
(sperm genotypes)
Here are the parents:
Mom = gene+
gene-
Mom’s alleles
(oocyte genotypes)
Dad = gene+
geneÆWhat proportion of offspring will make no gene product?
In fact, that many baby mice grew to be HUGE (like the one on the left in the picture). When the
researchers took a closer look, they noted that muscles were overdeveloping. They named the
protein made by their gene ‘myostatin’ to indicate that its role was to limit the growth (stasis) of
muscles (myo). The gene is therefore referred to as the myostatin gene.
ÆCircle the homozygous genotype in your Punnett square above.
ÆWhat do you predict from a cross between male and female mice of this genotype? Will all the
offspring look the same, or will there be different phenotypes?
For more information, see
(1) www.hopkinsmedicine.org/Press_releases/2004/06_23_04.html
(2) www.npr.com Research News, November 13, 2006, “Myostatin Therapies Hold Hope for
Muscle Diseases”, Jon Hamilton.
20
Muscular Mighty Mouse: Part 2
Mice and people are clearly not the same.
Why should you care about a muscular mouse?
There is a gene in people that transcribes and translates a protein that looks similar to mouse
myostatin, and this gene is therefore referred to as the ‘human myostatin gene’. Researchers
wondered whether the human gene might provide the same function as the mouse gene. It would
be useful to know this because one might be able to reverse muscle wasting diseases (such as
muscular dystrophy) by developing a drug that would inhibit the human myostatin. But how can
we know whether the human protein is really providing a function similar to the mouse protein?
An insightful doctor found evidence that it does. In 2002, a doctor who happened to know the
Mighty Mouse story was providing care for a baby boy in Germany who had muscle
development beyond that expected for his age. His advanced development was very unusual,
beyond anything this doctor had seen. The boy’s family agreed to find out whether he had
inherited any changes in his myostatin gene. In fact, both of his myostatin alleles were unable to
make a functional transcript – so he did not make myostatin protein. This strongly suggests that
human myostatin protein plays a role in humans similar to its role in mice.
Æ What does this make you expect to find in his parents’ genotypes? Write down what you
predict they will be. (MST = normal, functional gene; mst = nonfunctional gene)
As another point of interest, in 1997 researchers learned that a premier breed of cattle that
produces more meat also lacks myostatin protein due to a mutation. These are called Belgian
Blue. The cow mutation was naturally occurring, and the phenotype was captured by breeders
who noticed large muscled cows and bred them together.
Æ What do you expect the genotype of the Belgian Blue cows to be at the myostatin gene?
(They are pure-breeding for large muscle mass).
Now, for your information, you may be interested to know that the DNA sequence of myostatin
genes has been obtained from mice, humans, cows, pigs, turkeys, sheep, baboons, zebrafish, and
rats. There are relatively few differences in the proteins that are produced by genes in all of these
species.
For more information, see
(1) www.hopkinsmedicine.org/Press_releases/2004/06_23_04.html
(2) www.npr.com Research News, November 13, 2006, “Myostatin Therapies Hold Hope for
Muscle Diseases”, Jon Hamilton.
(3) McPherron AC and S-J Lee, Double muscling in cattle due to mutations in the myostatin
gene, Proc Nat Acad Sci USA 94:12457-12461 (1997).
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Human Gene CCRX5 and HIV Infection
The human CCR5 gene translates and transcribes a protein that ends up on the surface of
specialized white blood cells called macrophages. Macrophages are large cells that engulf and
digest debris that they encounter, including pathogens such as bacteria. Their job is to recognize
what does not belong (debris), to destroy it (by engulfing it), and to present parts of it to other
white blood cells which help in surrounding and neutralizing any threat the debris may pose to
the host organism.
The CCR5 protein on the macrophage cell surface acts as part of a docking station for Human
Immunodeficiency Virus (HIV), before it gains entry into this cell type. Cell entry is required for
HIV to replicate. The HIV copies made by replication will later be released from the infected cell
to find other macrophage cells to enter. And so an infection begins that can lead to acquired
immunodeficiency syndrome (AIDS).
Here is the interesting fact about CCR5: About 1 in 5 Caucasians of European descent have a 32
nucleotide deletion in the protein coding region of the CCR5 gene.
What will this mutation do to the CCR5 mRNA that is produced in transcription?
What will it do to the CCR5 protein made by translation?
You may not be surprised to learn that people with two mutant copies of the CCR5 gene are
relatively resistant to HIV infection. These people are _____zygous for the mutation.
In addition, people with one mutant copy and one standard copy (_____zygous people) show
reduced infection by the virus, presumably because their macrophages have a reduced amount of
CCR5 on the cell surface.
This is an example of a mutation that has a positive benefit under a specific circumstance:
exposure to HIV. Researchers have speculated that this mutation was favored during a
catastrophic disease occurring in northern Europe between 1,200 and 4,300 years ago. It is
imagined that this disease also used CCR5 protein to gain entry into macrophages, and people
who had the CCR5 deletion allele were among the few who survived. In this scenario, it is
believed that their children lived to repopulate much northern Europe. This would explain why
the CCR5 mutation is found among some people of European descent today.
For more information, see SJ O’Brien and M Dean, In Search of AIDS-Resistance Genes,
Scientific American, September 1997, pp 44-51.
22
DNA: what does it look like?
DNA: what how does it lead to traits?
DNA is in chromosomes: mitosis and meiosis
Mitosis and meiosis: where are they in the life cycle?
What, exactly, is a strawberry?
(2)
(1)
The fruit is part of a living organism.
The fruit is a food.
What, exactly, is a strawberry?
(2)
(3)
Mitosis and meiosis occur in the life cycle of most eukaryotic organisms.
Strawberry is a flowering plant.
(4)
Generalized diagram of a flower.
Meiosis produces:
pollen in anthers
ovule in ovary
Fertilization: leads to a seed
Here are pictures of a strawberry life cycle
(6)
(6)
(5)
(7)
(6)
(8)
(9)
Points to consider:
Nucleic acids are the basis for inheritance in all living things.
Meiosis promotes ‘reassortment’ of traits to generate a variety of individuals.
Mitosis promotes growth without ‘reassortment’.
Meiosis and mitosis both contribute to life cycles that are based on sexual
reproduction. Sexual reproduction occurs in most plants and animals.
DNA Extraction Lab
(10)
Mash the strawberry
Add extraction buffer
Water
Shampoo (detergent)
Salt
+
Collect liquid
Cell Disruption
Add Alcohol
gently; keep the layers separate
Let the mixture sit
Watch
------ (11)
use your stick to remove what forms at the interface
------
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
------
DNA
precipitation
------
Lassen
Shasta
Florida Ninety
Robinson
Tennessee Beauty
Midway
Dixieland
Pocahontas
(10)
Sparkle
Catskill
Marshall
Northwest
Variety Characteristics
Variety
Howard 17*
Howard 17*
Missionary
Missionary
Marshall
Marshall
* Premier
10=best
Location Production Firmness
MD
9
4
MA
10
6
FL
10
8
NC
8
5
OR
9
6
MD
1-3
3
Flavor
6
8
6-9
6-9
9
3-5
Color
7
8
8
7
8
5
Resistance Resistance
to Spot
to Scorch
9
9
9
9
7
7
6
6
7
9
3
7
How does chromosomal DNA
contribute to these phenotypes?
Data from (12)
Where does meiosis occur?
Where does mitosis occur?
What is the benefit of
meiosis? Of mitosis?
How does this life cycle
compare to ours?
(9)
Sources
1) www.nal.usda.gov/pgdic/Strawberry/darpubs.htm#book, Figure 19-1
2) www.ars.usda.gov/Services/docs.htm?docid=8597
3) www.vegparadise.com/highestperch45.html
4) www.shamefree.org/wp-content/uploads/2007/09/016_flower.jpg
5) http://strawberrygenes.unh.edu/strawinfo.html#octoploid
6) www.nal.usda.gov/pgdic/Strawberry/plates/plat19-2.htm
7) http://waynesword.palomar.edu/ecoph18.html
8) www.lima.ohio-state.edu/biology/archive/flowers.html
9) www.britannica.com
10) www.nal.usda.gov/pgdic/Strawberry/book/bokeigh.htm
11) www.csb.yale.edu
12) www.nal.usda.gov/pgdic/Strawberry/book/boktwnt3.htm
Genes generate proteins
4
5
Condensed chromosome
Diversity from
Inheritance
Sickle cell
anemia
mitosis
duplication
Phenotypes
from Proteins
recombination
segregation
or
Diverse gametes
Gamete
combinations
Inheritance
through families
Life cycle
Sexual reproduction:
one generation
6
Cystic Fibrosis
+
Haploid products
3
Transcription
mitosis
Meiosis promotes
diversity
2
Translation
Chromosomal
Replication
DNA
Mitosis is growth
cell cycle
1
Diversity from
Mutation
Image Credits
Chromosomal DNA
www.geneticengineering.org
Replication
http://images.google.com/imgres?imgurl=http://serc.carleton.edu/images/microbelife/microbservatories/methods/replication.v3.jpg&imgrefurl=http://s
erc.carleton.edu/microbelife/research_methods/genomics/transcrip.html&h=502&w=650&sz=112&hl=en&start=38&tbnid=GnHwbEiN_NpfSM:&tbnh
=106&tbnw=137&prev=/images%3Fq%3DDNA%2Breplication%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN
http://images.google.com/imgres?imgurl=http://kentsimmons.uwinnipeg.ca/cm1504/Image269.gif&imgrefurl=http://kentsimmons.uwinnipeg.ca/cm15
04/dnareplication.htm&h=561&w=800&sz=60&hl=en&start=91&tbnid=TvoABDtQHmxqwM:&tbnh=100&tbnw=143&prev=/images%3Fq%3DDNA%2
Breplication%26start%3D80%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN
Transcription
Mougey, EB et al Genes Dev 1609-1619 (1993)
http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/DNA_transcription.gif/800pxDNA_transcription.gif&imgrefurl=http://commons.wikimedia.org/wiki/Image:DNA_transcription.gif&h=442&w=800&sz=54&hl=en&start=36&t
bnid=fDruBMdnKoR3M:&tbnh=79&tbnw=143&prev=/images%3Fq%3Dtranscription%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN
Translation
http://images.google.com/imgres?imgurl=http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/nucleic/chpt15/transcription1.gif&imgrefurl=
http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/nucleic/chpt15/chpt15.htm&h=590&w=869&sz=142&hl=en&start=6&tbnid=KLRqmtkt2
sBAwM:&tbnh=98&tbnw=145&prev=/images%3Fq%3Dtranscription%26gbv%3D2%26hl%3Den%26sa%3DG
Cystic fibrosis
http://www.cbp.pitt.edu/bradbury/images/CFTR-model.gif
http://content.answers.com/main/content/wp/en-commons/d/d9/Mucoviscidose.PNG
Sickle cell anemia
http://www.koshland-science-museum.org/exhibitdna/inh04.jsp
Modified from www.dartmouth.edu
Phenotypes from proteins
http://www.thetech.org/genetics/ask.php?id=159
Cell cycle
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Meiosis/meiosis.htm
Mitosis
http://fig.cox.miami.edu/~cmallery/150/mitosis/mitosis.htm
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Meiosis/meiosis.htm
Condensed chromosome
http://cnx.org/content/m15083/latest/01%20Human%20Chromosome.JPG
Haploid products
http://homepage1.nifty.com
Gamete combinations
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_10/lect_10.htm
Inheritance through families
www.accessexcellence.org/ AE/AEPC/NIH/gene14.html
Sexual reproduction: one generation
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Meiosis/meiosis.htm
Life cycle
http://www.koshland-science-museum.org/exhibitdna/inh04.jsp
www.cosmosmagazine.com
www.voagno.org
http://www.brumm.com/genealogy/walkers_moyers/tour/biggroup3-1970.html
Mutation
http://publications.nigms.nih.gov/thenewgenetics/chapter1.html
http://images.google.com/imgres?imgurl=http://www.viewingspace.com/genetics_culture/images_genetics_culture/gc_assign/dna_replication.gif&imgrefurl=http:/
/www.viewingspace.com/genetics_culture/pages_genetics_culture/gc_assign/design_by_sequence.htm&h=555&w=246&sz=42&hl=en&start=27&tbnid=cNZ7QK4g3yqyM:&tbnh=133&tbnw=59&prev=/images%3Fq%3DDNA%2Breplication%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN l
Genes: More Than Just Letters 1
Name: __________________
Pre-lab Concept Mapping
Problem: How do amino acid sequences affect organisms’ traits?
Hypothesis: A change in amino acid sequence will ___________________
_____________________________________________________________.
Directions:
1. In the results table, examine the DNA nucleotide sequence for each
gene and transcribe the corresponding sequence of mRNA codons.
2. On the following line, record the tRNA anticodon sequence.
3. Use the mRNA decoder to translate the mRNA sequence into an
amino acid sequence.
4. Use the reference table and the amino acid sequences to find the traits
of your animal.
mRNA
Decoder
RESULTS
Results
Table
Gene A
DNA
Gene B
ACC GGT TAT
DNA
AGC CGA CCG AAT TTC
mRNA _______________________
mRNA ________________________
tRNA ________________________
tRNA _________________________
aa sequence ____________________ aa sequence _____________________
trait _________________________
trait __________________________
Gene C
Gene D
DNA
GGA CGC CGA AGT
DNA
TTT AAC
mRNA _______________________
mRNA ________________________
tRNA ________________________
tRNA _________________________
aa sequence ____________________ aa sequence _____________________
trait _________________________
trait __________________________
Gene E
DNA
Gene F
GGG AGG AAA CCC
DNA
GTC TTC CTA
mRNA _______________________
mRNA _______________________
tRNA ________________________
tRNA ________________________
aa sequence ____________________
aa sequence ____________________
trait _________________________
trait _________________________
Reference Table
Amino Acid Sequence (Gene)
Trait
Lysine - Leucine
four-legged
Asparagine - Cysteine
two legs, two wings
Tryptophan – Proline - Isoleucine
hairy
Glycine – Glutamine - Tyrosine
hairless
Proline – Alanine – Alanine - Serine
hooves
Leucine - Arginine – Leucine - Glutamine
claws
Serine – Alanine – Glycine – Leucine - Lysine
plump
Arginine – Leucine – Alanine - Stop
skinny
Proline – Proline – Leucine - Glycine
no stripes
Proline – Serine – Phenylalanine - Glycine
striped
Glutamine – Lysine – Aspartic acid
long nose, floppy ears
Arginine – Arginine - Isoleucine
short nose, pointed ears
5. Using all of the inherited traits draw and COLOR your animal below.
6. Name your animal: ________________________________________
7. When the teacher instructs you to, pair up with someone with a
different DNA sequence & compare your animals.
Summary Statement:
8. For homework, answer the post-lab questions.
Post-lab Questions:
Use COMPLETE SENTENCES for all questions, RESTATE the questions
and do not use “it” or “they.”
1. Describe OR draw transcription and translation. (If you describe, use
3 sentences minimum, if drawing, label the structures involved).
2. Where does transcription occur?
3. Where does translation occur?
4. How many nucleotides form a tRNA anticodon that binds to a mRNA
codon?
5. Suppose you knew the amino acid sequence of a protein. How could
you determine the DNA sequence of the protein?
6. How can one change in an amino acid sequence alter the function of a
protein?
More Than Just Letters Lab
Scores
Concept Map (complete, neat & correct terms)
5 4 3 2 1 0
Hypothesis (makes sense, correct)
5 4 3 2 1 0
Gene A (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene B (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene C (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene D (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene E (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene F (4 categories completed correctly, neat)
5 4 3 2 1 0
Drawing (colored, represents all traits)
5 4 3 2 1 0
Name (complete, creative)
2 1 0
Summary Statement (included, complete sentence)
2 1 0
Post-Lab Question 1 (requirements listed)
Questions 2- 4 (complete sentences, correct)
4 3
2 1 0
3 2 1 0
Question 5 (complete sentences, plausible)
2 1 0
Question 6 (complete sentences, correct)
2 1 0
Comments:
Raw Score:
/ 60
Percentage:
%
Genes: More Than Just Letters 2
Name: __________________
Pre-lab Concept Mapping
Problem: How do amino acid sequences affect organisms’ traits?
Hypothesis: A change in amino acid sequence will ___________________
_____________________________________________________________.
Directions:
1. In the results table, examine the DNA nucleotide sequence for each
gene and transcribe the corresponding sequence of mRNA codons.
2. On the following line, record the tRNA anticodon sequence.
3. Use the mRNA decoder to translate the mRNA sequence into an
amino acid sequence.
4. Use the reference table and the amino acid sequences to find the traits
of your animal.
mRNA Decoder
RESULTS
Results
Table
Gene A
DNA
Gene B
CCG GTT ATA
DNA
GCC GAC CGA ATT TCG
mRNA _______________________
mRNA ________________________
tRNA ________________________
tRNA _________________________
aa sequence ____________________ aa sequence _____________________
trait _________________________
trait __________________________
Gene C
Gene D
DNA
GAC GCC GAA GTT
DNA
TTA ACG
mRNA _______________________
mRNA ________________________
tRNA ________________________
tRNA _________________________
aa sequence ____________________ aa sequence _____________________
trait _________________________
trait __________________________
Gene E
DNA
Gene F
GGA GGA AAC CCG
DNA
TCT TCC TAG
mRNA _______________________
mRNA _______________________
tRNA ________________________
tRNA ________________________
aa sequence ____________________
aa sequence ____________________
trait _________________________
trait _________________________
Reference Table
Amino Acid Sequence (Gene)
Trait
Lysine - Leucine
four-legged
Asparagine - Cysteine
two legs, two wings
Tryptophan – Proline - Isoleucine
hairy
Glycine – Glutamine - Tyrosine
hairless
Proline – Alanine – Alanine - Serine
hooves
Leucine - Arginine – Leucine - Glutamine
claws
Serine – Alanine – Glycine – Leucine - Lysine
plump
Arginine – Leucine – Alanine - Stop
skinny
Proline – Proline – Leucine - Glycine
no stripes
Proline – Serine – Phenylalanine - Glycine
striped
Glutamine – Lysine – Aspartic acid
long nose, floppy ears
Arginine – Arginine - Isoleucine
short nose, pointed ears
Using all of the inherited traits draw and COLOR your animal below.
5. Name your animal: ________________________________________
6. When the teacher instructs you to, pair up with someone with a
different DNA sequence & compare your animals.
Summary Statement:
7. For homework, answer the post-lab questions.
Post-lab Questions:
Use COMPLETE SENTENCES for all questions, RESTATE the questions
and do not use “it” or “they.”
1. Describe OR draw transcription and translation. (If you describe, use
3 sentences minimum, if drawing, label the structures involved).
2. Where does transcription occur?
3. Where does translation occur?
4. How many nucleotides form a tRNA anticodon that binds to a mRNA
codon?
5. Suppose you knew the amino acid sequence of a protein. How could
you determine the DNA sequence of the protein?
6. How can one change in an amino acid sequence alter the function of a
protein?
More Than Just Letters Lab
Scores
Concept Map (complete, neat & correct terms)
5 4 3 2 1 0
Hypothesis (makes sense, correct)
5 4 3 2 1 0
Gene A (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene B (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene C (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene D (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene E (4 categories completed correctly, neat)
5 4 3 2 1 0
Gene F (4 categories completed correctly, neat)
5 4 3 2 1 0
Drawing (colored, represents all traits)
5 4 3 2 1 0
Name (complete, creative)
2 1 0
Summary Statement (included, complete sentence)
2 1 0
Post-Lab Question 1 (requirements listed)
Questions 2- 4 (complete sentences, correct)
4 3
2 1 0
3 2 1 0
Question 5 (complete sentences, plausible)
2 1 0
Question 6 (complete sentences, correct)
2 1 0
Comments:
Raw Score:
/ 60
Percentage:
%
EVALUATION CRITERIA HIGH SCHOOL GENETICS CURRICULUM MATERIALS
TITLE: Genes – Not Just Letters
SERIES TITLE: if applicable
AUTHOR(S): if applicable
CITY/STATE: where published
PUBLISHER/SOURCE:
COPYRIGHT DATE:
ISBN NO:
ADVERTISED GRADE LEVEL(S): grades(s)
SUPPLIES: availability of materials and kits for core curriculum materials
COST: suggested list price
RESOURCE TYPE: student activity book, teacher's guide, books on teaching science, etc.
URL if available:
SUBJECT:
REVIEWER’S NAME: Forrest Spencer, Christine Roberts
DATE OF REVIEW: June 13, 2008
GRADE LEVEL(S) RECOMMENDED BY REVIEWER IF DIFFERENT FROM THE ADVERTISED LEVEL(S) STATED ABOVE:
(Please circle the specific grade level(s) for which you believe these materials are most appropriate or just delete
the grade levels that are not applicable.)
7
8
9
10
11
12
GENETICS CONTENT COVERAGE
The 2007 GENA partnerships will be focusing on Patterns of Inheritance. After reviewing your resource, please indicate which
topics under this broad theme the resource covers by placing an “X” next to the topic. If we have missed a topic(s) you feel relevant,
you may add it under “other.”
__Meiosis
__Linkage
_X_Human genetic disorders
__Polygenic inheritance
_X_Pedigree Analysis
__Social Issues in Genetics
__Recombination
_X_Alleles
__Complementation
__Role of the environment
__Non-Mendelian inheritance
__Mendelian genetics/probability
__Sex determination
__Epistasis
__Imprinting
__Other- Please Specify ______________________
__Other- Please Specify ______________________
After reviewing the resource, please reflect upon how well this tool addresses the following areas of pedagogy and content. Please place
your score, 1 through 10 in the box to the right with 10 being the highest rating and 1 being the lowest. If you would like to add
comments on why you scored something in a particular way or would like to comment on specific strengths and weaknesses, feel free to
do so in the comments section.
Criteria
How well does the material address the important goals a high school teacher
would have for the teaching of major principles in Patterns of Inheritance?
Comments:
This activity addresses an important challenge in high school genetics by
illustrating the connections between gene expression and inherited
characteristics. These concepts are presented over the course of several
weeks. This activity reinforces the big picture.
How well does the material focus on inquiry and activity as the basis of learning
experiences?
Comments:
This is an activity in which students are asked to link concepts from DNA
structure through phenotype themselves as they follow structured steps.
How developmentally appropriate are the modes of instruction, writing style and
materials and equipment utilized?
Rating
9
9
10
Comments:
The activity is appropriate for high school students and teachers. The
expectations are clear and it is a creative, good evaluation of student mastery
of the process of transcription and translation. Students are able to
understand what is being asked of them and teachers are able to evaluate
understanding with a pencil-paper activity that engages the students. It also
allows reinforcement of the connections between often isolated topics of
DNA, protein synthesis, mutation and inheritance of traits.
8
How accurate is the science content presented?
Comments:
The relationships among transcription and translation elements are
accurate. The actual genetic code and phenotypes are entirely imaginary, but
obviously so, as a practical matter. The genetic code used is too short to
represent a typical gene and requires comment to clarify.
How well do the suggested investigations (if applicable) lead to an understanding
of basic concepts and principles of science?
Comments:
n/a
How well does this resource reflect the unbiased nature of science (i.e. is the
resource free of dogmatism)?
Comments:
n/a
How engaging would high school students find this activity?
Comments:
The students are engaged actively as they transcribe and translate the code.
It is just long enough to avoid tedium. Although the traits are imaginary, it
is an effective method to maintain their interest as they explore a real
scientific concept. It also challenges them at the end of the activity to figure
out exactly what caused the changes by working collaboratively with other
groups.
How well does the material define scientific terminology and concepts?
Comments:
This activity requires that students recognize the structural and functional
relationships among elements of gene expression leading to phenotype. This
requires precise vocabulary. The scientific terminology employed is
accurate, with the exception of the students’ application of imaginary
phenotypes to a provided short DNA sequence.
Does the content provide sufficient information for the teacher to effectively
conduct the activity in the context of a complete learning cycle?
Comments:
Yes- perhaps though, more instruction to complete the Pre-lab concept
mapping- I suggest including the terms for students to use to complete the
concept map. (this is a concept map to go over protein synthesis)
Does the content provide sufficient information for the teacher to conduct an
effective assessment of student understanding?
Comments:
Yes.
Are the materials required easily obtained and affordable for the average high
school classroom?
Comments:
Yes.
n/a
n/a
10
9
7
10
10
RECOMMENDATION BASED ON ALL CRITERIA
Instructions: Complete the section below. If you "recommend with reservations" or "do not
recommend" a material for inclusion, briefly state your primary reason in the space provided.
Based upon all aspects of my review of this material,
________ I highly recommend this material.
X
I recommend this material.
________ I recommend this material with reservations.
Primary reasons for reservations:
________ I do not recommend this material.
Primary reasons for rejection:
This document was created using the official National Science
Resource Center Evaluation Criteria for Curriculum Materials
designed for Middle Schools and adapted for our use.