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Questions and Answers
What feature of the pea plant made it suitable for Mendel's studies on inheritance?
What feature of the pea plant made it suitable for Mendel's studies on inheritance?
- It requires cross-pollination for reproduction.
- It had a long life cycle.
- It had perfect flowers allowing self-fertilization. (correct)
- It could be grown in diverse environments.
In Mendelian genetics, what does the term 'locus' refer to?
In Mendelian genetics, what does the term 'locus' refer to?
- The combination of alleles in an individual.
- The physical location of a gene on a chromosome. (correct)
- The variation of a gene found on a chromatid.
- The phenotype expressed by an organism.
Which aspect of Mendel's experiments primarily focused on single traits?
Which aspect of Mendel's experiments primarily focused on single traits?
- He examined the overall plant characteristics.
- He paid attention to one character at a time. (correct)
- He used multiple gene traits in all experiments.
- He used random assortments of traits for each experiment.
What does the term 'allele' specifically refer to in genetics?
What does the term 'allele' specifically refer to in genetics?
What was a critical methodological aspect of Mendel's experiments?
What was a critical methodological aspect of Mendel's experiments?
What basic principle of inheritance did Mendel establish through his work?
What basic principle of inheritance did Mendel establish through his work?
What is the main characteristic of a 'dihybrid' cross in Mendelian genetics?
What is the main characteristic of a 'dihybrid' cross in Mendelian genetics?
What describes 'heterozygous' genotype?
What describes 'heterozygous' genotype?
What type of traits did Mendel primarily investigate in his experiments?
What type of traits did Mendel primarily investigate in his experiments?
What does the 'law of segregation' state?
What does the 'law of segregation' state?
What does the term 'hybrid' refer to in Mendel's experiments?
What does the term 'hybrid' refer to in Mendel's experiments?
In Mendel's F1 generation, what was observed regarding the traits of height?
In Mendel's F1 generation, what was observed regarding the traits of height?
What ratio was observed in the F2 generation when tall hybrid plants were self-fertilized?
What ratio was observed in the F2 generation when tall hybrid plants were self-fertilized?
What does the principle of segregation describe in Mendelian genetics?
What does the principle of segregation describe in Mendelian genetics?
Which term is used to describe an organism with two different alleles for a trait?
Which term is used to describe an organism with two different alleles for a trait?
What characteristic of genotypes is observed when both alleles are the same, such as DD or dd?
What characteristic of genotypes is observed when both alleles are the same, such as DD or dd?
What does the term 'phenotype' refer to in genetics?
What does the term 'phenotype' refer to in genetics?
Which of the following statements is true regarding Mendel’s dominant and recessive traits?
Which of the following statements is true regarding Mendel’s dominant and recessive traits?
What does the artificial cross-fertilization method allow Mendel to do?
What does the artificial cross-fertilization method allow Mendel to do?
In the context of Mendel's experiments, what is meant by 'purity of gametes'?
In the context of Mendel's experiments, what is meant by 'purity of gametes'?
What is the primary purpose of a testcross in genetics?
What is the primary purpose of a testcross in genetics?
Which of the following statements about segregation is true?
Which of the following statements about segregation is true?
In the inheritance of a trait, what must be true for a recessive allele to be phenotypically expressed?
In the inheritance of a trait, what must be true for a recessive allele to be phenotypically expressed?
What distinguishes a backcross from a testcross?
What distinguishes a backcross from a testcross?
What outcomes may occur when crossing a heterozygous tall plant (Dd) with a homozygous dwarf plant (dd)?
What outcomes may occur when crossing a heterozygous tall plant (Dd) with a homozygous dwarf plant (dd)?
Which characteristic of recessive alleles makes them undetectable in carriers?
Which characteristic of recessive alleles makes them undetectable in carriers?
Which generation is referred to as the F1 generation in Mendelian genetics?
Which generation is referred to as the F1 generation in Mendelian genetics?
How can researchers experimentally identify recessive alleles?
How can researchers experimentally identify recessive alleles?
What is the result of segregation during gamete formation in heterozygous individuals?
What is the result of segregation during gamete formation in heterozygous individuals?
Flashcards
Gregor Mendel
Gregor Mendel
An Austrian monk who studied inheritance in pea plants, discovering fundamental principles of heredity.
Pea plants
Pea plants
Organisms used by Mendel; easy to cultivate, short life cycle, observable traits.
Basic principles of heredity
Basic principles of heredity
Fundamental rules governing how traits are passed from parents to offspring.
Discontinuous characteristics
Discontinuous characteristics
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Gene
Gene
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Protein
Protein
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Chromosome
Chromosome
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Locus
Locus
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Allele
Allele
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Quantitative approach
Quantitative approach
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Monohybrid
Monohybrid
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Dominant Trait
Dominant Trait
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Recessive Trait
Recessive Trait
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Homozygous
Homozygous
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Heterozygous
Heterozygous
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Phenotype
Phenotype
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Genotype
Genotype
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Hybrid
Hybrid
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Principle of Segregation
Principle of Segregation
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Testcross
Testcross
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Backcross
Backcross
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Recessive alleles
Recessive alleles
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Carrier
Carrier
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Study Notes
Mendelism
- Gregor Mendel was an Austrian monk who studied botany and mathematics.
- He carried out groundbreaking studies on inheritance using pea plants.
- He discovered the basic principles of heredity.
Reasons for choosing the pea plant
- Pea plants are easy to cultivate and have a relatively short life cycle.
- Pea plants have discontinuous characteristics, like flower color and pea texture, making them ideal for studying inheritance.
- Pea plants are self-fertilizing, meaning the ovule is fertilized by pollen from the same flower.
Features of Mendel's Experiment
- Mendel focused on one character at a time, for example, the shape of the seeds.
- Characters are noticeable features that vary among individuals.
- Traits are variations of a character.
Key Definitions
- Gene: A length of DNA that codes for a particular protein.
- Protein: Determines an inherited trait.
- Chromosome: Genes reside on chromosomes.
- Locus: The location of a gene on a chromosome.
- Allele: A variation of a gene. Each homologous chromosome has one allele.
Mendel's Quantitative Approach
- Mendel carefully counted the number of offspring of each type to determine the proportions of inherited traits.
- This quantitative approach was crucial to his findings.
Mendel's Experiment
- To prevent self-fertilization, Mendel removed anthers from "test" flowers.
- He studied traits with alternative forms, like tall vs. dwarf pea plants.
- He crossed tall plants with dwarf plants and vice versa (
P1generation). - The offspring of this cross (
F1generation) were called hybrids. - When the F1 plants were self-fertilized, some offspring were tall and some were dwarf (
F2generation). - The resulting ratio was nearly 3:1 (tall:dwarf).
Additional Terminology
- Hybrid: Offspring resulting from combining traits of two different organisms.
- Monohybrid: A heterozygous hybrid concerning a specified gene (e.g., the offspring of tall and dwarf peas, they are hybrid for only one characteristic).
- Dominant Trait: The trait that appears in the heterozygous condition (e.g., tallness in peas).
- Recessive Trait: The trait that only appears in the homozygous recessive condition (e.g., dwarfness in peas).
- Homozygous: Individuals with two identical alleles for a trait (e.g.,
DDordd). - Heterozygous: Individuals with two different alleles for a trait (e.g.,
Dd). - Phenotype: The visible expression of a trait (e.g., the color of a flower).
- Genotype: The genetic makeup of an organism (e.g.,
DD,Dd, ordd).
Principles of Segregation
- During sexual reproduction, the alleles for a trait separate into different gametes.
- Fertilization brings two alleles together again, resulting in offspring with two factors for each trait.
- This is known as the principle of segregation.
Mendel's Findings
- The separation of alleles is only detected in the heterozygous parent.
- Homozygous recessive individuals produce only one type of gamete.
Testing the Principle
- Testcross: Crossing an organism with an unknown genotype to a known homozygous recessive organism.
- Backcross: Crossing the F1 generation back to one of their parents or an individual with a parental genotype.
Recessiveness
- Recessive alleles are only expressed in homozygous individuals.
- Carriers (heterozygous individuals) do not display the recessive trait.
- Testcrosses are used to identify recessive alleles.
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Description
Explore the foundational principles of heredity as discovered by Gregor Mendel in his experiments with pea plants. This quiz covers the key concepts of genes, traits, and Mendel's methodology in studying inheritance. Test your understanding of why pea plants were chosen and the significance of Mendel's work in genetics.
