Heredity & Genetics
Essential Questions
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 How are traits passed down from parents to their children?
Why do some traits appear to skip a generation, while others do not skip generations?
 What are the chances that certain traits will be passed on to future generations?
Mastery Objectives
What to know and be able to do:
Gregor Mendel’s Discoveries
a)
b)
c)
d)
e)
f)
g)
h)
List several features of Mendel’s experimental design that contributed to his success.
Define true breeding, hybrid, monohybrid cross, P generation, F1 & F2 generations.
Identify and explain Mendel’s three laws.
Use a Punnet square to predict the results of a monohybrid cross and state the phenotypic and
genotypic rations of the F2 generation.
Distinguish between the following pairs of terms: dominant and recessive; heterozygous and
homozygous; genotype and phenotype.
Explain how a test cross can be used to determine if a dominant phenotype is homozygous or
heterozygous.
Use a Punnet square to predict the results of a dihybrid cross and state the phenotypic and
genotypic ratios of the F2 generation.
Explain why Mendel was wise to use large sample sizes in his studies.
Extending Mendelian Genetics
a) Explain how the phenotypic expression of the heterozygote is affected by complete
dominance, incomplete dominance, and co-dominance.
b) Explain why dominant alleles do not necessarily mean that the allele is more common in a
population. Illustrate your explanation with the character polydactyly (having 6 digits).
c) Describe the inheritance of the ABO blood system and explain why the IA and IB alleles are
said to be co-dominant.
d) Define polygenic inheritance and give examples of some human traits controlled in this way.
e) Describe how one gene may affect the expression of others as in the case of albinism.
Mendelian Inheritance in Humans
a) Explain why studies of human inheritance are not as easily conducted as Mendel’s work with
his peas.
b) Given a simple family pedigree, be able to determine whether the trait is dominant, recessive
or sex linked.
c) Generate the genotypes for family members in a pedigree.
d) Be able to describe the relationships between people pictured in a pedigree
e) Given a family description, be able to draw a pedigree.
Sex Chromosomes
a) Explain how sex is genetically determined in humans.
b) Explain why sex-linked diseases are more common in human males.
c) Describe the inheritance patterns and symptoms of color blindness, Duchene muscular
dystrophy, and hemophilia.
Errors and Exceptions in Chromosomal Inheritance
a) Distinguish among nondisjunction, trisomy, and monosomy. Explain how these major
chromosomal changes occur and describe the consequences.
b) Distinguish among deletions, duplications, inversions, and translocations in chromosomes.
c) Describe the type of chromosomal alterations implicated in the following human disorders:
Down syndromes, Turner’s syndrome, and chronic myelogenous leukemia.
Genetic Disorders
For the following conditions, discuss such aspects as the biological cause, the mode of inheritance,
possible means of detection and/or prevention and the population that is most often affected.
a. Phenylketonuria (PKU)
b. Sickle cell anemia
c. Down syndrome
d. Tay-Sachs
e. Hemophilia
f. Turner’s Syndrome
g. Huntington’s Disease
Cell Division and Reproduction:
1. Which cell structures are involved in the processes of mitosis and meiosis
2. What are the purposes of mitosis and meiosis?
3. Be able to put unlabeled diagrams into the right order for meiosis. Be able to name the phase
pictured in a diagram.
4. How do the cells that result from mitosis and meiosis differ? How are they the same?
5. Define and distinguishe between the terms diploid and haploid. What are the diploid and
haploid numbers for humans? Given a type of cell, decide whether it is haploid or diploid and
how many chromosomes it has. Example = dogs have a diploid number of 64, how many
chromosomes would be in an unfertilized dog egg? _______ how many in a dog muscle cell?
_____ how many in a dog fetal cell? _____
6. What are homologous chromosomes?
7. What are the chromosomal differences between human males and females?
8. Compare and contrast somatic cells and gametes
9. How does meiosis in males and females differ?
10. Identify difference between sexual and asexual reproduction
11. What are the advantages and disadvantages of sexual and asexual reproduction?
12. Why is reproduction important?
13. What are the types of asexual reproduction?
14. What types of organisms reproduce sexually, which asexually?
15. How do internal and external fertilization compare?
16. From the Trails of Life film, be able to discuss some general reproductive strategies of
animals. Example = external fertilization requires more gametes released such as the
Christmas Island Crabs and the Giant Clam.