UNIT 5: Gene Expression and Inheritance
5C: Genetic Inheritance
Roadmap for the year:
Themes for the year:
Unit 1: Interconnectedness of Life
Unit 2: Ecological Biochemistry
Unit 3: Cellular Biology: Structure Leads to Function
Unit 4: DNA Structure and Cellular Reproduction
Unit 5: Gene Expression and Inheritance
 5A- Gene Expression
 5B- Sexual Reproduction and Meiotic Cell
Division
 5C- Genetic Inheritance
Unit 6: Evolution and Classification of Living Things
Unit 7: Biotechnology, Human Biology, and Disease
How does this unit
contribute to your
understanding of the
following themes?
 Life on Earth has
various Levels of
Organization
 The Structure of
Living Things leads
to their Function
The Big Picture…
 Genes code for proteins that can be expressed as traits.
 Predictions are useful in determining genetic inheritance.
Big Picture Questions:
1. How are an organism’s genes expressed as its traits?
2. Why do some organisms look similar to family members and some look so different?
Suggested Resources…
Textbook – Biology (Miller and Levine, 2010) (Sections 11.1, 11.2, 11.3, 11.4, 14.1, 14.2)
Notes packets
Homework worksheets
Lab activity packets
PowerPoint presentations
Media resources (videos, images, Internet)
By the conclusion of this unit, you should
know the following:
1. Gregor Mendel is known as the “Father of
Genetics” due to his studies of genetic inheritance
in pea plants.
2. The basic rules of inheritance are referred to as
“Mendel’s Laws” (including the Law of Dominance
& Recessiveness of Alleles, Law of Segregation,
and the Law of Independent Assortment). Not all
genes follow the patterns of classic Mendelian
Inheritance.
3. Each diploid cell contains two copies of every
gene (a maternal and paternal copy for each gene
locus).
4. Punnett Squares and the product rule are
mathematical tools used to predict/solve one-trait
or two-trait genetics problems (including
probabilities of genotypes and phenotypes or
working backwards to identify parental
genotypes).
5. Predicted results do not always match
actual/observed results.
6. Genotypes determine phenotypes.
7. Some forms of a gene (dominant) may be able to
prevent others (recessive) from being expressed
as part of the organism’s phenotype.
8. The definitions of basic genetic terms including:
heterozygous, homozygous, dominant, recessive,
purebred, hybrid, alleles, traits, gene loci,
maternal, paternal, P1/F1/F2, self-pollination,
cross-pollination, genotype, phenotype, test
cross.
9. In humans, the 23rd pair of chromosomes
determine the sex of an organism (XX=girl;
XY=boy).
10. Genes found on the 23rd pair of chromosomes are
called “sex-linked” and show unique patterns of
inheritance.
11. Human blood types are determined by a
combination of classic dominance, co-dominance
and multiple alleles.
12. There are a number of other factors which affect
the expression and inheritance of genes,
including polygenic traits and the environment.
 A pedigree is a visual representation of the
genotypes and phenotypes of a particular trait as
it is passed on through several generations.
By the conclusion of this unit, you should
be able to do the following:
1. Distinguish between the terms: alleles, traits,
gene loci, maternal, paternal, P1/F1/F2, selfpollination, cross-pollination, heterozygous,
homozygous, purebred, hybrid, test cross.
2. Give examples of physical, physiological and
behavioral traits.
3. Weigh different arguments involved in the nature
vs. nurture debate.
4. Determine phenotypes based on genotypes.
5. Describe Mendel’s studies and conclusions
about inheritance, and how these contributed to
our understanding of genetics.
6. Describe how alleles segregate and assort
independently during reproduction.
7. Use the product rule and/or Punnett Squares to
predict/solve one-trait or two-trait genetics
problems (including probabilities of genotypes
and phenotypes or working backwards to identify
parental genotypes) involving classic dominance,
incomplete dominance, codominance, sexlinkage, multiple alleles.
8. Differentiate between predicted and
actual/observed results of genetic crosses.
9. Explain how a trait can be “hidden” or “skip” a
generation.
10. Construct and analyze pedigrees to study traits.
11. Be able to explain why some experiments
produce data different from that predicted by
Mendel’s Laws.
 Based on prior knowledge of protein synthesis,
propose an explanation for the differences
between complete and incomplete/codominance.
Genetic Inheritance Vocabulary
Words Found in the Glossary (Chapter 11)
1. Genetics
2. Alleles
3. Trait
4. Gene
5. Hybrid
6. Fertilization
7. Principle of dominance
8. Segregation
9. Gamete
10.Homozygous
11.Heterozygous
12.Phenotype
13.Genotype
14.Punnett square
15.Independent assortment
16.Probability
17.Incomplete dominance
18.Codominance
19.Multiple allele
20.Polygenic trait
21.Homologous
(Chapter 14)
22.Sex-linked gene
23.Pedigree
Words not found in the glossary
24.Heredity
25.Gregor Mendel
26.Dominant
27.Recessive
28.Self-pollination
29.Cross pollination
30.P/F1/F2
31.Purebred
32.Gene locus
33.Maternal
34.Paternal
35.Monohybrid
36.Dihybrid
37.Expected vs. observed results
38.Carrier