Questions and Answers
Who was Gregor Mendel?
Father of Genetics. Found the principles of genetics by breeding garden peas.
What plant did Gregor Mendel study and why?
Garden Peas. They grow quickly.
What is the difference between a character and a trait?
A character is a heritable feature that varies among individuals, while a trait is each variant for a character.
What is the difference between self-fertilization and cross-fertilization?
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What is a true-breeding variety?
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How did Mendel ensure that each variety of garden peas was true-breeding for a particular trait?
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Define: Hybrid.
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Define: Cross.
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What is a monohybrid cross?
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Define: Alleles.
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Explain the terms homozygous and heterozygous.
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Define Dominant.
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Define Recessive.
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How are dominant and recessive alleles represented?
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Briefly explain Mendel's four hypotheses.
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What is the difference between a genotype and a phenotype?
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What is a Punnett square?
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Explain the difference between a monohybrid cross and a dihybrid cross.
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In a dihybrid cross, what approximate ratio of plants expressing contrasting traits did Mendel calculate in his F2 generation of garden peas?
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Explain the law of independent assortment.
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Explain a test cross.
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What is the purpose of a family pedigree?
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Explain the differences between recessive and dominant disorders. (Know examples of each and their symptoms)
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When considering genetic disease, what is a carrier?
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Define: Inbreeding.
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Study Notes
Gregor Mendel and Genetics
- Gregor Mendel is known as the Father of Genetics.
- He discovered genetic principles through his work with garden peas.
Study Organism
- Garden peas were chosen for study due to their rapid growth.
Characters and Traits
- A character is a heritable feature that varies among individuals.
- A trait is a specific variant of a character.
Fertilization Methods
- Self-fertilization results in offspring genetically identical to the parent.
- Cross-fertilization involves gametes from two different individuals.
True-Breeding
- A true-breeding variety consistently produces offspring identical to itself through self-fertilization.
Ensuring True-Breeding
- Mendel achieved true-breeding by self-fertilizing plants with specific traits.
Hybrid Definition
- A hybrid is the offspring of parents from two different species or varieties, and it is usually heterozygous.
Genetic Cross
- A cross refers to the mating of two sexually reproducing individuals for genetic experimentation.
Monohybrid Cross
- A monohybrid cross examines the inheritance of a single character.
Alleles
- Alleles are alternative versions of a gene responsible for variations in traits.
Genotypes
- Homozygous genotype: identical alleles (AA or aa).
- Heterozygous genotype: different alleles (Aa).
Dominant and Recessive Alleles
- Dominant allele: determines appearance in heterozygous pairs.
- Recessive allele: has no observable effect in heterozygous pairs.
- Dominant alleles are represented by capital letters; recessive alleles by lowercase letters.
Mendel's Hypotheses
- Alternative alleles lead to trait variation.
- Organisms inherit two alleles, one from each parent.
- Dominant alleles mask recessive alleles.
- Allele pairs segregate during gamete formation (Law of Segregation).
Genotype vs. Phenotype
- Genotype: genetic composition of a trait.
- Phenotype: observable characteristics of a trait.
Punnett Square
- A Punnett square is a diagram used to predict genetic variation from fertilization.
Crossing Types
- A monohybrid cross involves one character; a dihybrid cross involves two characters.
Dihybrid Cross Ratios
- Mendel calculated specific ratios of contrasting traits in the F2 generation of a dihybrid cross.
Law of Independent Assortment
- This law states that the segregation of alleles for one character occurs independently of the alleles for another character.
Test Cross
- A test cross is used to determine the genotype of an individual by crossing with a homozygous recessive.
Purpose of Family Pedigree
- A family pedigree charts the inheritance of traits across generations.
Disorders: Recessive vs. Dominant
- Recessive disorders require two copies of the mutated gene; dominant disorders need only one.
- Symptoms and examples vary between disorder types.
Genetic Disease Carrier
- A carrier has one copy of a recessive allele but does not exhibit symptoms of the disorder.
Inbreeding
- Inbreeding is the mating of closely related individuals, increasing genetic similarity in offspring.
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Description
This quiz covers key concepts from Chapter 9 of BIO 101, focusing on genetics and the foundational work of Gregor Mendel. You'll explore the distinction between characters and traits as well as the significance of garden peas in Mendel's experiments. Perfect for reinforcing your understanding of genetic principles.