Site MapHelpFeedbackeLearning Connection
eLearning Connection
(See related pages)

ConceptsQuestionsMedia Resources
23.1 Mendel's Laws
Today it is known that alleles (alternate forms of a gene), located on chromosomes, control the traits of individuals.

Mendel discovered certain laws of heredity after doing experiments with garden peas during the mid-1800s.

The law of segregation states that each organism contains two factors for each trait, and the factors segregate during formation of gametes.

A testcross can be used to determine the genotype of an individual with the dominant phenotype.

The law of independent assortment states that every possible combination of parental factors is present in the gametes.
1. Explain the difference between "genotype" and "phenotype."

2. When considering two alleles for each of two traits that are located on different chromosomes, why will gametes contain every possible combination of the traits?
Essential Study Partner
Monohybrid Cross
Dihybrid Cross

Art Quiz
Mendel's Experiment Results
Dihybrid Cross

General Biology Weblinks
Mendelian Genetics

Constructing a Genetic Map
Heredity in Families
Gene Segregation within Families
23.2 Genetic Disorders
Many genetic disorders are inherited according to Mendel's laws.

The pattern of inheritance indicates whether the disorder is a recessive or a dominant disorder.

Dominant genetic disorders appear if a single dominant allele is inherited; recessive genetic disorders require the inheritance of two recessive alleles.
3. When considering genetic diseases, what is a "carrier?"
Cystic Fibrosis
23.3 Beyond Simple Inheritance Patterns
Polygenic traits include skin color, behavior, and various syndromes.

Blood type is controlled by multiple alleles and exhibits codominance.

Some traits, like sickle-cell disease, are incompletely dominant.
4. Are there any human polygenic disorders? Explain.

5. If a woman has type O blood, could a man with type AB conceive children with type O blood? Explain.
Essential Study Partner
Beyond Mendel

Art Quizzes
Continuous Variation
Incomplete Dominance
Multiple Alleles - ABO Blood Groups

Inquiry into LifeOnline Learning Center with Powerweb

Home > Chapter 23 > eLearning Connection