Genetics
Genetics
Objectives
In this unit, students will learn how genetic information is expressed, as well as comparing different patterns of inheritance. Students will discover how heredity follows certain patterns based on the laws of probability and explore inheritance of genetic disorders and issues with identifying and treating afflicted people. Students will:
- compare and contrast Mendelian and non-Mendelian patterns of inheritance.
- explain the processes of transcription, translation, and protein modification.
- identify and explain how genetic information is expressed.
- explore the relationships between advancements in technology and innovative biological studies.
Essential Questions
Related Unit and Lesson Plans
Related Materials & Resources
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Materials haven't been entered into the unit plan.Formative Assessment
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Multiple-Choice Items:
1. Which trait can disappear for one or more generations before reappearing?
A
Heterozygous
B
Homozygous
C
Recessive
D
Dominant
2. Which of the following is the mRNA sequence for the DNA template shown below?
5'AAGTAGGCATACC3'
A
3'AAGUAGGCAUACC5'
B
3'UUCAUCCGUAUGG5'
C
3'CCAUACGGUAGAA5'
D
3'UUGAUGGCAAUCC5'
3. Where does transcription take place?
A
Nucleus
B
Cytoplasm
C
Rough ER
D
Golgi Apparatus
4. A gardener crosses a rose that is pink and homozygous for a weak scent (RR'ss) with a pink rose that heterozygous for a strong scent (RR'Ss). The gardener would like to get a white rose (R') with a strong scent (S). If the cross produces 80 plants, approximately how many will be whites with a strong scent?
A
About 50 %
B
About 25%
C
About 12 %
D
About 8%
5. The discovery of which feature or process provided evidence that helped support Mendel’s Law of Segregation?
A
Nucleus
B
Chromosomes
C
Mitosis
D
Meiosis
6. A family is afflicted with Tay-Sachs disease. According to the family’s pedigree chart below, which of the following correctly describes Tay-Sach’s disease?
A
Autosomal dominant
B
Autosomal recessive
C
Codominant
D
Sex-linked
7. During translation, the anticodon on the tRNA makes a temporary bond with the codons on the mRNA. How many nucleotides make a codon?
A
One
B
Two
C
Three
D
Four
8. Individuals with Down syndrome have an extra copy of chromosome 21. What kind of chromosomal mutation is this?
A
Polyploidy
B
Monosomy
C
Triploidy
D
Trisomy
9. Which type of mutation has no effect on an individual human?
A
Silent mutation
B
Nonsense mutation
C
Missense mutation
D
Frame-shift mutation
Multiple-Choice Answer Key:
1. C
2. B
3. A
4. C
5. D
6. B
7. C
8. D
9. A
Short-Answer Items:
10. A child who has curly hair will have a parent who has curly hair. Red hair, however, often skips generations before reappearing in a child. Use Mendel’s ideas to explain how some traits, like curly hair, are seen in every generation but some traits are not.
11. Make a flow chart detailing the process of protein synthesis. Label parts for transcription and translation, and where each occurs. Describe the roles of the DNA, mRNA, tRNA, ribosome, and amino acids during protein synthesis. Indicate what starts and stops the process.
Short-Answer Key and Scoring Rubrics:
10. A child who has curly hair will have a parent who has curly hair. Red hair, however, often skips generations before reappearing in a child. Use Mendel’s ideas to explain how some traits, like curly hair, are seen in every generation but some traits are not.
People have two alleles for a gene. Genes reside on the chromosome. One chromosome came from the mother and one from the father during fertilization. Dominant traits will be expressed even when only one copy of the allele is present. That is why the trait has to be seen in the parent as well. Recessive traits can only be expressed if two alleles are present. The allele can be present for many generations but not be expressed when the dominant allele is also present. That is why the trait skips generations.
Points
Description
2
- The student explains that individuals have two alleles for each trait.
- The student correctly explains that dominant traits will be expressed when there is only one allele present.
- The student correctly explains that an individual needs two recessive alleles to express the trait.
1
- The student explains that individuals have two alleles for each trait.
- The student does not explain that dominant traits will be expressed when there is only one allele present.
OR
- The student does not explain that an individual needs two recessive alleles to express the trait.
0
- The student does not explain that individuals have two alleles for each trait.
- The student does not explain that dominant traits will be expressed when there is only one allele present.
- The student does not explain that an individual needs two recessive alleles to express the trait.
11. Make a flow chart detailing the process of protein synthesis. Label parts for transcription and translation, and where each occurs. Describe the roles of the DNA, mRNA, tRNA, ribosome, and amino acids during protein synthesis. Indicate what starts and stops the process.
Points
Description
2
- The student correctly sequences the events of transcription and translation.
- The student correctly indicates that transcription occurs in the nucleus and translation occurs on the rough ER.
- The student correctly distinguishes between the roles of the DNA, mRNA, tRNA and ribosomes.
1
- The student correctly sequences the events of transcription and translation.
- The student correctly indicates that transcription occurs in the nucleus and translation occurs on the rough ER.
- The student does not distinguish between the roles of the DNA, mRNA, tRNA, and ribosomes.
0
- The student correctly sequences the events of transcription and translation.
- The student does not indicate that transcription occurs in the nucleus and translation occurs on the rough ER.
- The student does not distinguish between the roles of the DNA, mRNA, tRNA and ribosomes.
Performance Assessment:
The pedigree below shows the trait Methemoglobinemia (Hmet). Individuals who have the disorder, shown here with filled-in circles, have hemoglobin that cannot carry oxygen, turning their red blood cells brown.
1. Does Methemoglobinemia appear to be caused by a dominant or recessive trait? Justify your answer.
2. Label all known genotypes:
homozygous (HH or HmHm)
heterozygous (H Hm)
3. Use a Punnett square to determine the probability of a couple AB having an affected child.
Performance Assessment Scoring Rubric:
Points
Description
5
The student completes all five of the requirements:
- The student correctly identifies the trait as recessive and explains that it is recessive because the parents don’t have to express the trait in order for the children to have it.
- Student identifies all individuals with the trait to be homozygous recessive.
- Student identifies parents and children who are heterozygous.
- Student uses a Punnett square to perform a cross between the homozygous female and heterozygous male.
- Student recognizes a 50% probability that the child of parents AB will be affected.
4
The student completes four of the requirements.
- The student correctly identifies the trait as recessive and explains that it is recessive because the parents don’t have to express the trait in order for the children to have it.
- Student identifies all individuals with the trait to be homozygous recessive.
- Student identifies parents and children who are heterozygous.
- Student uses a Punnett square to perform a cross between the homozygous female and heterozygous male, but does not recognize it as a probability.
3
The student completes three of the requirements.
- The student correctly identifies the trait as recessive and explains that it is recessive because the parents don’t have to express the trait in order for the children to have it.
- Student identifies all individuals with the trait to be homozygous recessive.
- Student identifies parents and children who are heterozygous.
2
The student completes two of the requirements.
- The student correctly identifies the trait as recessive and explains that it is recessive because the parents don’t have to express the trait in order for the children to have it.
- Student identifies all individuals with the trait to be homozygous recessive.
1
The student completes one of the requirements.
- The student correctly identifies the trait as recessive and explains that it is recessive because the parents don’t have to express the trait in order for the children to have it.
0
The student demonstrates lack of understanding or does not attempt to complete the assessment.
The Punnett square shows a probability:
- 50% will be HHm or normal.
- 50% will be HmHm or affected.
DRAFT 05/26/2011
