Genetics Chapter 3 Flashcards

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Questions and Answers

What term describes an individual possessing two of the same alleles at a gene locus?

heterozygous

wild type

homozygous (correct)

monohybrid

dihybrid

When Mendel crossed a plant homozygous for round seeds to another plant homozygous for wrinkled seeds, how can this be explained?

The allele for round seeds is dominant to the allele for wrinkled seeds. (correct)

The progeny were homozygous for the allele for round seeds.

The allele for round seeds is recessive to the allele for wrinkled seeds.

The parent that was homozygous for round seeds underwent self-pollination.

Segregation of alleles in the two parents produced gametes with both alleles.

Mendel's principle of segregation can be explained by what process?

fertilization

mitosis

none of these

testcross

meiosis (correct)

What is a cross that occurs between two individuals that differ in two characteristics?

dihybrid cross Signup and view all the answers

If an Aa individual is crossed to an aa individual, what will be the phenotypic ratio in the offspring?

1:1 Signup and view all the answers

A cross between an AABB individual and an aabb individual will produce what type of offspring?

All will be AaBb Signup and view all the answers

An individual possesses two alleles at a locus and these two alleles separate when gametes are formed. What is this genetic concept known as?

principle of segregation Signup and view all the answers

What is a shorthand method for predicting outcomes of genetic crosses?

Punnett square Signup and view all the answers

What is the physical appearance or manifestation of a characteristic called in genetics?

phenotype Signup and view all the answers

What information can the chi-square goodness-of-fit test provide?

how well the observed results of a genetic cross fit the expected values Signup and view all the answers

What value represents the number of ways in which the expected classes are free to vary in the chi-square goodness-of-fit test?

degrees of freedom Signup and view all the answers

What will be the genotypic ratio in the offspring of two Aa parents that are crossed with each other?

1:2:1 Signup and view all the answers

If a plant has a genotype of Aa, we would assume which is true?

The A allele is dominant to the a allele. Signup and view all the answers

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?

The deviation between the expected and observed outcomes is not caused by chance alone. Signup and view all the answers

In a sample cross, the number of different expected phenotypes is five. What is the correct value for the degrees of freedom (df)?

4 Signup and view all the answers

Which value is not required for the chi-square test?

age of parents at the time of cross Signup and view all the answers

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.