Question 1

Which of the following best describes Mendel’s experimental approach with garden peas that allowed him to deduce the basic principles of inheritance?

Accepted Answer

He cross-pollinated true-breeding varieties and analyzed the resulting generations.

Question 2

In Mendel’s monohybrid cross between true-breeding purple-flowered and white-flowered pea plants, all F1 offspring had purple flowers. What does this result demonstrate?

Accepted Answer

The purple allele is dominant over the white allele.

Question 3

If two heterozygous tall pea plants (Tt) are crossed, what is the probability that an offspring will be homozygous recessive (tt)?

Accepted Answer

$$\frac{1}{4}$$

Question 4

Which of Mendel’s postulates explains why alleles for different traits are distributed to gametes independently?

Accepted Answer

Independent assortment.

Question 5

A plant with genotype GgWw can produce which of the following gametes?

Accepted Answer

GW, Gw, gW, gw

Question 6

In a dihybrid cross between two heterozygous plants (YyRr x YyRr), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

9:3:3:1

Question 7

If a mouse with a dominant phenotype (P-) is crossed with a homozygous recessive mouse (pp) and some offspring show the recessive phenotype, what is the genotype of the original mouse?

Accepted Answer

Pp

Question 8

How many genetically distinct gametes can a human produce, given $$n = 23$$ pairs of chromosomes?

Accepted Answer

$$2^{23}$$

Question 9

Which equation is used to calculate the chi-square ($$\$$chi^2$$) value in genetic experiments?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(o-e)^2$}{e}$$

Question 10

In a cross between BbGG and Bbgg individuals, what phenotypic ratio is expected among the offspring if the genes assort independently?

Accepted Answer

1:1

Question 11

What is the probability that two heterozygous parents (Aa x Aa) will have two children, both of whom are homozygous recessive (aa)?

Accepted Answer

$$\frac{1}{16}$$

Question 12

Which of the following best explains why Mendel’s work was not appreciated for over 30 years after its publication?

Accepted Answer

His results were inconsistent with the blending theory of inheritance.

Question 13

A testcross is used to determine the genotype of an individual with a dominant phenotype. Which cross would you perform?

Accepted Answer

Cross with a homozygous recessive individual.

Question 14

If the probability of obtaining a head in a coin toss is $$\frac{1}{2}$$, what is the probability of obtaining one head and one tail when tossing a penny and a nickel simultaneously?

Accepted Answer

$$\frac{1}{2}$$

Question 15

Which of the following statements about the chromosomal theory of inheritance is correct?

Accepted Answer

Genes are located on chromosomes, which segregate and assort independently during meiosis.

Question 16

In a trihybrid cross (AaBbCc x AaBbCc), what is the probability of producing an offspring with the genotype aabbcc?

Accepted Answer

$$\frac{1}{64}$$

Question 17

Which of the following is a consequence of independent assortment during gamete formation?

Accepted Answer

Genetic variation among offspring increases.

Question 18

A pedigree analysis is most useful for which of the following?

Accepted Answer

Revealing patterns of inheritance of human traits.

Question 19

If the observed ratio in a genetic cross deviates from the expected Mendelian ratio, which statistical test would you use to determine if the deviation is due to chance?

Accepted Answer

Chi-square ($$\$$chi^2$$) test

Question 20

What is the degree of freedom for a chi-square test in a dihybrid cross with four possible phenotypic categories?

Accepted Answer

3

Mendelian Genetics: Principles, Experiments, and Applications

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