Question 1

Gregor Mendel conducted his experiments on pea plants without knowledge of which of the following biological concepts?

Accepted Answer

Chromosomes and meiosis

Question 2

In Mendel's monohybrid cross between true-breeding yellow and green seed plants, what was the phenotypic ratio observed in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

Which of Mendel’s postulates explains why the offspring of a cross between two heterozygotes can display both dominant and recessive traits?

Accepted Answer

Segregation of unit factors during gamete formation

Question 4

A tall pea plant (genotype D-) is crossed with a short pea plant (genotype dd). If the tall plant is heterozygous, what proportion of the offspring will be short?

Accepted Answer

$$1/2$$

Question 5

In a dihybrid cross of pea plants with genotypes $$RrYy 	imes RrYy ($$where R = round, r = wrinkled, Y = yellow, y = green), what is the expected proportion of offspring with round, yellow seeds?

Accepted Answer

$$9/16$$

Question 6

Which experimental approach did Mendel use to determine whether a tall plant was homozygous or heterozygous for the tall allele?

Accepted Answer

Testcross with a recessive homozygote

Question 7

If a true-breeding plant with axial flowers and yellow, inflated pods is crossed with a true-breeding plant with terminal flowers and green, constricted pods, what will the F1 generation look like?

Accepted Answer

All F1 plants will have axial flowers and yellow, inflated pods

Question 8

Which of the following best describes a heterozygous genotype?

Accepted Answer

Two different alleles for a gene

Question 9

In Mendel’s experiments, what was the result of reciprocal crosses between true-breeding plants for a given trait?

Accepted Answer

The results were identical regardless of which parent carried the trait

Question 10

A plant with genotype $$Dd is $$self-fertilized. What is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:2:1 (DD$$:Dd:dd)

Question 11

If you cross a true-breeding tall plant with white flowers to a true-breeding short plant with purple flowers, what will the F1 generation look like?

Accepted Answer

All F1 plants will be tall with purple flowers

Question 12

Which law allows you to calculate the probability of an F2 plant having a specific combination of traits in a dihybrid cross?

Accepted Answer

Product law of probability

Question 13

In a cross between $$Dd ($$tall) and $$dd ($$short) pea plants, what is the expected phenotypic ratio of tall to short offspring?

Accepted Answer

$$1:1$$

Question 14

If you cross two F1 heterozygous plants ($$Dd$$), what fraction of the F2 generation will be homozygous recessive?

Accepted Answer

$$1/4$$

Question 15

A dihybrid cross is performed between two plants heterozygous for seed shape and color ($$RrYy 	imes RrYy). $$What is the expected proportion of offspring with wrinkled, green seeds?

Accepted Answer

$$1/16$$

Question 16

In a cross between a true-breeding tall plant with white flowers and a true-breeding short plant with purple flowers, what is the probability that an F2 plant will be short with purple flowers and green pods?

Accepted Answer

$$9/64$$

Question 17

Which of the following statements about Mendel’s 4th postulate (independent assortment) is correct?

Accepted Answer

Traits are inherited independently, allowing prediction of genotypic frequencies using the product law

Question 18

Which scenario would best allow you to distinguish between a homozygous dominant and a heterozygous individual for a trait?

Accepted Answer

Crossing with a homozygous recessive

Question 19

If a plant with genotype $$Dd is $$crossed with a plant with genotype $$dd$$, what is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:1 (Dd$$:dd)

Question 20

Which of the following is NOT a key feature of Mendel’s experimental design that contributed to his success?

Accepted Answer

He had knowledge of chromosomes and meiosis

Mendelian Genetics: Sep 3

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