Questions and Answers
What term describes an individual possessing two of the same alleles at a gene locus?
When Mendel crossed a plant homozygous for round seeds to another plant homozygous for wrinkled seeds, how can this be explained?
Mendel's principle of segregation can be explained by what process?
What is a cross that occurs between two individuals that differ in two characteristics?
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If an Aa individual is crossed to an aa individual, what will be the phenotypic ratio in the offspring?
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A cross between an AABB individual and an aabb individual will produce what type of offspring?
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An individual possesses two alleles at a locus and these two alleles separate when gametes are formed. What is this genetic concept known as?
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What is a shorthand method for predicting outcomes of genetic crosses?
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What is the physical appearance or manifestation of a characteristic called in genetics?
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What information can the chi-square goodness-of-fit test provide?
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What value represents the number of ways in which the expected classes are free to vary in the chi-square goodness-of-fit test?
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What will be the genotypic ratio in the offspring of two Aa parents that are crossed with each other?
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If a plant has a genotype of Aa, we would assume which is true?
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A chi-square test comparing the observed and expected number of progeny gave a p-value of 0.016. What does this p-value represent?
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In a sample cross, the number of different expected phenotypes is five. What is the correct value for the degrees of freedom (df)?
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Which value is not required for the chi-square test?
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Study Notes
Genetic Terminology and Concepts
- Homozygous: An individual with two identical alleles at a gene locus.
- Dominant vs. Recessive Alleles: In Mendel's pea plant experiments, round seed allele is dominant over the wrinkled seed allele.
- Dihybrid Cross: A genetic cross that examines the inheritance of two different traits.
Mendelian Genetics
- Principle of Segregation: Alleles separate into different gametes during meiosis, ensuring each gamete carries only one allele for each gene.
- Phenotypic Ratio of Aa x aa Cross: Results in a 1:1 ratio of phenotypes.
- Progeny from AABB x aabb Cross: All offspring will be heterozygous AaBb.
Genetic Predictions and Ratios
- Punnett Square: A tool used for predicting the outcomes of genetic crosses by calculating expected genotype and phenotype ratios.
- Genotypic Ratio of Aa x Aa Cross: Produces a 1:2:1 ratio among offspring.
Chi-Square Test in Genetics
- Purpose: Assesses how well observed genetic outcomes fit expected ratios.
- Degrees of Freedom: In a chi-square test, calculated as the number of phenotypic classes minus one, which reflects the variability in expected classes.
- Significance of p-value: A p-value (e.g., 0.016) indicates that differences between expected and observed results are unlikely to be due to chance alone (statistically significant).
Miscellaneous Genetic Concepts
- Phenotype: The observable traits or characteristics of an organism resulting from the interaction of its genotype with the environment.
- Expected Progeny Counts: Necessary for conducting a chi-square test, alongside observed counts and the expected ratio.
- Information Not Required: The age of the parents at the time of cross is irrelevant for the chi-square calculation.
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Description
Test your knowledge of key genetics terms with these flashcards from Chapter 3. Learn about concepts like homozygous and how Mendel's experiments on seed shapes explain inheritance patterns. Perfect for students studying genetic principles.