Focus Plan
Texarkana Independent School District
GRADING
PERIOD:
WRITER:
Biology – 2nd, Chemistry – 3rd
PLAN CODE:
L. Petty
COURSE/SUBJECT:
10th grade science
GRADE(S):
10th
TIME ALLOTTED
FOR INSTRUCTION:
1-½ hours, 3 hours if Heredity
Mystery is used as follow-up
TITLE:
I Like Your Genes
LESSON TOPIC:
How traits are carried on DNA and passed on to offspring.
TAKS OBJECTIVE:
Objective 2
The student will demonstrate an understanding of the organization of living
systems.
10.6 The student knows the structures and functions of nucleic acids in the
mechanisms of genetics. The student is expected to:
(a) compare genetic variations observed in plants and animals
Objective 1: The student will demonstrate an understanding of the nature of
science.
10.2 The student uses scientific methods during field and laboratory
investigations. The student is expected to:
(A) plan and implement investigative procedures including asking
questions, formulating testable hypotheses, and selecting equipment
and technology
(C) organize, analyze, evaluate, make inferences, and predict trends from
data
(D) communicate valid conclusions
FOCUS TEKS AND STUDENT
EXPECTATION:
SUPPORTING TEKS AND
STUDENT EXPECTATIONS:
CONCEPTS
Heredity
ENDURING UNDERSTANDINGS/GENERALIZATIONS/PRINCIPLES
The student will understand that
Traits, or characteristics, are passed from parent to offspring.
Genes
The units of heredity are called genes.
Dominance
The stronger gene is the dominant gene, and is the one that is expressed in the trait.
The weaker, recessive gene, is masked.
If the gene for a trait is the same, the trait is homozygous or pure. If the gene is
mixed, the trait is heterozygous.
The observable physical characteristics of an individual that are a result of its
genotype.
Genotype
Phenotype
I.
SEQUENCE OF ACTIVITIES (INSTRUCTIONAL STRATEGIES)
A.
Focus/connections/anticipatory set
Have the following questions on the board when students enter the classroom.
If B codes for brown hair, what color hair would a person with the genotype Bb have?
Is it possible for this student to have a blond-haired child?
Answer: The person would have brown hair but could have a blond-haired child if their partner
also carries a recessive b gene.
B.
Instructional activities
(demonstrations, lectures, examples, hands-on experiences, role play, active learning experience, art,
music, modeling, discussion, reading, listening, viewing, etc.)
A. Lecture
Go over the vocabulary definitions on Transparency master – Vocabulary
C.
Guided activity or strategy
Pass out a small piece of PTC paper to each student (instruct them not to do anything with them until they are
told to do so). After each student has a piece, instruct them to touch just the tip of the paper to their tongue.
Ask the students what they can taste. Tasters usually describe a bitter taste like dissolving aspirin, non-tasters
just taste paper.
On their data tables, ask the students what possible genotype they can have if they exhibit the dominant trait
“taster”. (TT or Tt are both possible unless they know whether a parent is a taster or until they have
children.)
If they only taste paper, they can tell exactly what their genotype is (tt) since a recessive trait is only
expressed if it is the only gene present.
Instruct students not to do the class totals until everyone is done, and then put those two columns on the
board and complete them together.
D.
Accommodations/modifications
Students requiring accommodations should be given a copy of the vocabulary transparency
E.
Enrichment
None needed
II.
STUDENT PERFORMANCE
A.
Description
Complete Lab Worksheet – I Like You Genes and Lab Worksheet – Heredity Mystery.
B.
Accommodations/modifications
Students requiring accommodations should be assigned a peer tutor.
C.
Enrichment
Students requiring enrichment should be assigned as a peer tutor.
III.
ASSESSMENT OF ACTIVITIES
A.
Description
Grade Lab Worksheet – I Like Your Genes and Lab Worksheet – Heredity Mystery
B.
Rubrics/grading criteria
Grade Lab Worksheet – I Like Your Genes with each box in the table worth 1 point each and each
question worth 4 points each
Grade Lab Worksheet – Heredity Mystery with each space worth 1 point and the correct child with 10
points.
C.
Accommodations/modifications
For students requiring enrichment, give the correct child on Heredity Mystery as a bonus. Questions 9 & 10
may also be graded with some leniency, since they are harder questions.
D.
Enrichment
Students requiring enrichment should answer all questions for a grade.
E.
Sample discussion questions
1.
2.
3.
4.
5.
6.
IV.
How would you express a homozygous dominant for green eyes? GG
How would you express a heterozygous for green eyes? Gg
How would you express a blue-eyed trait? gg
If someone has green eyes, is this a genotype or phenotype? phenotype
If someone has green eyes, explain how it is possible to have a blue-eyed child. They can carry a
recessive trait for blue eyes.
If someone has blue eyes and marries someone with blue eyes, can they have a green-eyed child? No, if
the green gene is present in either parent, it is dominant so that parent will have green eyes.
TAKS PREPARATION
A.
Transition to TAKS context
1. Gregor Mendel performed quantitative experiments with the genetic variation of garden peas during the
mid-1800s. He chose varieties having traits that were easily distinguished, such as plant height, flower
color, etc.
What additional trait variation examined by Gregor Mendel is illustrated in the drawing above?
(a) seed color
(b) flower position
(c) seed shape
(d) pod shape
2. Qualitative experiments performed by Gregor Mendel during the mid-1800s led to formation of a theory to
explain genetic variation in plants and animals. Mendel experimented with garden peas because they have
traits that are easily distinguished.
What genetic variation in pea plants examined by Gregor Mendel is illustrated in the drawing above?
(a) seed shape
(b) seed color
(c) pod shape
(d) pod color
3. Biologists can use a Punnett square to predict the results of crossing plants that breed true for a pair of
contrasting traits. The Punnett square below illustrated data about a pair of plants that are homozygous for
the tested trait.
What is observed by biologists who examine offspring of the first-generation cross between plants that are
homozygous dominant and homozygous recessive for height?
(a) All first-generation plants will grow to medium height.
(b) There will be three tall plants to each short plant in the first generation.
(c) All first-generation plants will grow tall.
(d) There will be three short plants to each tall plant in the first generation.
B.
Sample TAKS questions
Spring 2003
1. Dogs (Canis familiaris) are most closely related genetically to which of the following organisms?
(a) African hunting dog (Lycaon pictus)
(b) Gray wolf (Canis lupus)
(c) Grizzly bear (Ursus arctos)
(d) Domestic cat (Felis catus)
Spring 2004
1. DNA molecules separate into single strands, which are then used to construct two identical strands of
DNA. This process ensures that the ____.
(a) cytoplasm is in equilibrium
(b) mitochondria are genetically identical to the chloroplasts
(c) parent cells use little ATP
(d) daughter cells are genetically identical to the parent cells
2. 3’AATCGC5’
Which of the following nucleotide base sequences complements the section of DNA modeled above?
(a) 5’UTCGCA3’
(b) 5’TTAGCG3’
(c) 5’GCGATT3’
(d) 5’TTUCGC3’
3. According to the table, which of the following phenotypes would probably occur in all the offspring from
the parents shown above?
(a) Solid gray fur
(b) Striped gray fur
(c) Green eyes
(d) Blue eyes
4. A pea plant with the genotype TtWW is crossed with a pea plant with the genotype ttWw. How many
different genotypes can be expressed in the offspring?
(a) 1
(b) 2
(c) 3
(d) 4
V.
KEY VOCABULARY
Dominant trait
Gene
Genotype
Heterozygous
VI.
Homozygous
Phenotype
Recessive trait
Sex-linked trait
RESOURCES
A.
Textbook
None needed
B.
Supplementary materials/equipment
Lab Worksheet – I Like Your Genes
Instructor’s Copy – I Like Your genes
Trait Diagrams
Lab Worksheet – Heredity Mystery
Instructor’s Copy – Heredity Mystery
Heredity Mystery Information Sheet
Transparency master - Vocabulary
C.
VII.
Technology
FOLLOW UP ACTIVITIES
(reteaching, cross-curricular support, technology activities, next lesson in sequence, etc.)
A. Reteaching
Go over lab questions
B. Follow-up activity
Heredity Mystery (information also included with this lesson plan)
VIII.
TEACHER NOTES
Before lab:
1. Make a transparency of the Transparency Master
2. Run off a copy of each Lab Worksheet for each student.
3. Run off a copy of the Trait Diagrams and Heredity Mystery Information Sheet for each pair of students.
4. Go through the clues of Heredity Mystery and make sure the clues are clear and that the correct answer can be
reached.
5. Set up pairs of students. They will need to look at each other because some of the traits observed are not easily
seen by the person with the traits.
During lab:
1. Spot check and make sure students are recording TT or Tt (for example) for dominant traits. Explain that they do
not know which genotype they have unless one of their parents expresses the recessive trait or unless they have
children that express the recessive trait. Both of these situations will indicate Tt.
2. During Heredity Mystery, make sure students understand that “and has been for generations” and similar statements
are used to indicate homozygous dominant.