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What type of inheritance is indicated by a phenotype being influenced by two or more genes?
What type of inheritance is indicated by a phenotype being influenced by two or more genes?
What is the expected phenotypic ratio among F2 offspring resulting from independent assortment in the provided example?
What is the expected phenotypic ratio among F2 offspring resulting from independent assortment in the provided example?
What does the term 'norm of reaction' refer to?
What does the term 'norm of reaction' refer to?
Which of the following statements about polygenic characters is true?
Which of the following statements about polygenic characters is true?
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How can environmental factors influence phenotype?
How can environmental factors influence phenotype?
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What is the main flaw in the blending hypothesis of heredity?
What is the main flaw in the blending hypothesis of heredity?
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Which hypothesis suggests that traits retain their identities during inheritance?
Which hypothesis suggests that traits retain their identities during inheritance?
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What term do geneticists use to refer to heritable features?
What term do geneticists use to refer to heritable features?
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Why did Mendel choose to work with garden peas for his experiments?
Why did Mendel choose to work with garden peas for his experiments?
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What describes the variants for a character, such as flower color?
What describes the variants for a character, such as flower color?
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Mendel's experiments demonstrated that heritable traits could be traced through generations by tracking:
Mendel's experiments demonstrated that heritable traits could be traced through generations by tracking:
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What is the concept of the 'gene idea' primarily associated with?
What is the concept of the 'gene idea' primarily associated with?
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Which color of flowers did Mendel use in his experiments to study inheritance?
Which color of flowers did Mendel use in his experiments to study inheritance?
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What term describes the process of crossing two true-breeding varieties in Mendel's experiments?
What term describes the process of crossing two true-breeding varieties in Mendel's experiments?
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Which generation results from the cross-pollination of the P generation?
Which generation results from the cross-pollination of the P generation?
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According to Mendel's Law of Segregation, what happens to alleles during gamete production?
According to Mendel's Law of Segregation, what happens to alleles during gamete production?
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What do we call the offspring produced by self-pollinating the F1 generation?
What do we call the offspring produced by self-pollinating the F1 generation?
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If an organism has two different alleles for a character, what is true about its appearance?
If an organism has two different alleles for a character, what is true about its appearance?
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What defines an organism as being homozygous?
What defines an organism as being homozygous?
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What are the fundamental principles of heredity that Mendel identified through the F2 generation?
What are the fundamental principles of heredity that Mendel identified through the F2 generation?
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What happens to variations in inherited characters?
What happens to variations in inherited characters?
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What will happen to the alleles if the organism is heterozygous for a trait?
What will happen to the alleles if the organism is heterozygous for a trait?
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In Mendel's experiments with pea plants, what characteristics did he primarily study?
In Mendel's experiments with pea plants, what characteristics did he primarily study?
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What is the genetic makeup of an organism called?
What is the genetic makeup of an organism called?
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Which of the following genotypes would produce a purple flower phenotype?
Which of the following genotypes would produce a purple flower phenotype?
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In the context of a testcross, what does crossing a purple pea flower (unknown genotype) with a white flowered pea (pp) help determine?
In the context of a testcross, what does crossing a purple pea flower (unknown genotype) with a white flowered pea (pp) help determine?
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In a dihybrid cross involving seed color and seed shape, which alleles are dominant?
In a dihybrid cross involving seed color and seed shape, which alleles are dominant?
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What is the significance of dominance and recessiveness in relation to phenotypes?
What is the significance of dominance and recessiveness in relation to phenotypes?
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Which of the following is NOT true regarding a heterozygous organism?
Which of the following is NOT true regarding a heterozygous organism?
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When crossing a true breeding purple flowered pea and a white flowered pea, what is the expected phenotype of the offspring?
When crossing a true breeding purple flowered pea and a white flowered pea, what is the expected phenotype of the offspring?
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Which concept explains whether two traits, like seed color and shape, are transmitted independently?
Which concept explains whether two traits, like seed color and shape, are transmitted independently?
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What does the phenotype of an organism reflect?
What does the phenotype of an organism reflect?
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In a genetic cross where the offspring display a combination of traits from both parents, what is the genotypic ratio generally expected in a dihybrid cross?
In a genetic cross where the offspring display a combination of traits from both parents, what is the genotypic ratio generally expected in a dihybrid cross?
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What phenotypic ratio results from the independent assortment of two characters in the F1 generation?
What phenotypic ratio results from the independent assortment of two characters in the F1 generation?
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What is the term used for different forms of a gene that can exist in a population?
What is the term used for different forms of a gene that can exist in a population?
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In incomplete dominance, what phenotype results from the crossing of red and white snapdragons?
In incomplete dominance, what phenotype results from the crossing of red and white snapdragons?
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What happens when individuals with the IA and IB alleles are crossed?
What happens when individuals with the IA and IB alleles are crossed?
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Which of the following describes the phenomenon where both alleles are fully expressed in the phenotype?
Which of the following describes the phenomenon where both alleles are fully expressed in the phenotype?
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What is pleiotropy in genetics?
What is pleiotropy in genetics?
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In the context of epistasis, what does a homozygous recessive genotype at one gene locus affect?
In the context of epistasis, what does a homozygous recessive genotype at one gene locus affect?
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What is the expected phenotype ratio of the F2 generation when F1 hybrids of snapdragons are crossed?
What is the expected phenotype ratio of the F2 generation when F1 hybrids of snapdragons are crossed?
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How can mismatch in blood type during transfusion affect the recipient?
How can mismatch in blood type during transfusion affect the recipient?
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What is meant by the term 'dominance' in genetics?
What is meant by the term 'dominance' in genetics?
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Study Notes
Cell & Molecular Biology - Mendel, Genes & Chromosomal Inheritance
- Mendel's work focused on inheritance using garden peas
- Heritable traits, such as eye color, hair color, were observed in populations
- The "blending" hypothesis proposes that genetic material mixes like paint
- This hypothesis contradicts everyday observations and doesn't explain traits skipping generations
- An alternative is the "particulate" hypothesis (gene idea): parents pass discrete traits like marbles, not blending
- Genes are passed on to generations without dilution
- Geneticists use "character" for heritable features like flower color
- Each variant of a character (e.g., purple or white flowers) is called a "trait"
- Mendel's pea experiments utilized controlled plant breeding with self-fertilizing pea plants
- Mendel tracked discrete traits with distinct alternatives ("either-or" traits), like purple or white flowers
- "True-breeding" varieties meant all offspring were of the same variety when self-pollinated
- Mendel's experiments involved hybridization: mating two contrasting varieties
- The hybrid offspring were called the F₁ generation
- F₁ generations were allowed to pollinate creating F₂ offspring
- Observations of F₂ generation revealed segregation and independent assortment
- Research reveals that the two alleles for a trait separate when gametes are formed
- If alleles differ, one (dominant) is expressed; the other, recessive, has minimal visible effect
- Alleles are segregated during gamete production
- A testcross involves crossing a plant with a known genotype that is recessive for a trait
- This helps determine the genotype of a plant with an unknown genotype
- A dihybrid cross tracks two characters, such as seed color and shape. Resulting genotypes/phenotypes follow a 9:3:3:1 ratio which proves traits segregate independently
- Modern genetics has extended beyond Mendel's initial observations
- Traits are more complex (not simple either/or) with various types of dominance
- Incomplete dominance leads to a middle ground phenotype (e.g., pink snapdragons)
- Codominance means both alleles are expressed (e.g., human blood types)
- Multiple alleles occur for a gene impacting phenotypes (e.g., ABO blood groups)
- Polygenic traits have multiple genes contributing to a phenotype (e.g., human skin color)
- Pleiotropy is the ability of a single gene to affect multiple traits
- Epistasis is when one gene's action influences another gene's expressed phenotype (e.g., coat color in mice)
- The environment influences the expression of the genotype resulting in phenotypic variation and the norm of reaction
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Description
Explore the foundational concepts of Mendelian genetics through his experiments with garden peas. This quiz covers key terms, theories, and the significance of inheritance patterns observed by Mendel. Test your understanding of heritable traits, the particulate hypothesis, and how genetic traits are passed through generations.
