Question 1

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genetic makeup, while phenotype refers to the observable traits.

Question 2

A researcher is studying the inheritance of flower color in a plant species. Red flowers (R) are dominant to white flowers (r). If two heterozygous plants (Rr) are crossed, what is the expected ratio of red to white flowers in the offspring?

Accepted Answer

3:1

Question 3

Which equation would you use to calculate the expected genotype frequencies in a population under Hardy-Weinberg equilibrium?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 4

A population of mice has two alleles for fur color: B (black) and b (brown). If the frequency of B is 0.6 and b is 0.4, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2(0.6)(0.4) = 0.48$$

Question 5

Which of the following is NOT an assumption of the Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection is occurring

Question 6

In a chi-square test, which formula is used to calculate the chi-square statistic?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O - E)^2$}{E}$$

Question 7

A scientist performs a chi-square test to determine if the observed ratio of pea plant phenotypes fits the expected 9:3:3:1 ratio. If the calculated $$\$$chi^2$$ value is less than the critical value, what should the scientist conclude?

Accepted Answer

Accept the null hypothesis; the data fit the expected ratio.

Question 8

Which of the following best explains why large sample sizes are important in genetic studies?

Accepted Answer

They reduce the impact of sampling error and make statistical tests more reliable.

Question 9

A population of butterflies has a genotype frequency of AA = 0.25, Aa = 0.50, and aa = 0.25. Is this population in Hardy-Weinberg equilibrium?

Accepted Answer

No, because the genotype frequencies do not match the expected $$p^2$$, $$2pq$$, $$q^2$$ values.

Question 10

Which of the following scenarios would most likely violate the assumption of random mating in a population?

Accepted Answer

Individuals mate only with those of similar phenotype.

Question 11

If a population is not in Hardy-Weinberg equilibrium, which of the following could be a possible cause?

Accepted Answer

Genetic drift

Question 12

Which of the following is a real-world application of the chi-square test in genetics?

Accepted Answer

Determining if observed offspring ratios match Mendelian predictions

Question 13

A student calculates a chi-square value of 5.99 for a genetic cross with 2 degrees of freedom. If the critical value at $$p = 0.05 is 5.99$$, what is the correct interpretation?

Accepted Answer

The null hypothesis is rejected; the observed data do not fit the expected ratio.

Question 14

Which of the following best describes the purpose of using a null hypothesis in a chi-square test?

Accepted Answer

To provide a baseline for comparison to determine if observed data differ significantly from expected values

Question 15

In a population, the frequency of allele A is 0.7 and allele a is 0.3. What is the expected frequency of the homozygous recessive genotype under Hardy-Weinberg equilibrium?

Accepted Answer

$$q^2$$ = $$(0.3)^2 = 0.09$

Question 16

Which of the following would be considered a phenotype?

Accepted Answer

The observable color of a flower

Question 17

A population of 1000 individuals has 360 with genotype AA, 480 with Aa, and 160 with aa. What is the frequency of allele A?

Accepted Answer

$$\frac{360 	imes 2 + 480}{2000} = 0.6$$

Question 18

Which of the following is an example of a real-world violation of Hardy-Weinberg equilibrium?

Accepted Answer

A population where individuals migrate in and out frequently

Question 19

Why is it important to use the correct degrees of freedom when interpreting a chi-square test?

Accepted Answer

It determines the critical value needed to accept or reject the null hypothesis.

Genetics, Chromosomes, and Introduction to Statistics (Chi-Square) – Study Guide

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