Question 1

A monohybrid cross is performed between two heterozygous purple-flowered pea plants (Pp x Pp). What is the expected phenotypic ratio among the offspring?

Accepted Answer

$$3:1$$

Question 2

In a dihybrid cross between two plants with genotypes $$YyRr ($$yellow, round), what is the probability of obtaining an offspring that is green and wrinkled?

Accepted Answer

$$1/16$$

Question 3

A black rabbit (dominant, $$A) is $$crossed with a white rabbit (recessive, $$a). $$All $$F_1$$ offspring are black. If two $$F_1$$ rabbits are crossed, what proportion of the $$F_2$$ generation will be white?

Accepted Answer

$$1/4$$

Question 4

Which of the following offspring ratios is expected from a Mendelian heterozygous cross examining one gene?

Accepted Answer

$$3:1$$

Question 5

A wild-type male and an albino female have 8 children: 4 wild-type and 4 albino. Which of the following parental genotypes is most likely?

Accepted Answer

$$Aa 	imes aa$$

Question 6

If you cross a homozygous dominant purple, square plant ($$PPSS) $$with a homozygous recessive pink, spherical plant ($$ppss$$), what proportion of the $$F_1$$ generation will be purple and spherical?

Accepted Answer

$$1$$

Question 7

Which of the following gametes cannot be formed from the genotype $$AaBbCc$$?

Accepted Answer

Question 8

Two organisms with the genotypes $$AaBbCcDdEe$$ and $$AaBbCcDdEe$$ are crossed. What is the probability that an offspring will have the genotype $$aabbccdde$$?

Accepted Answer

$$1/256$$

Question 9

According to Mendel's Law of Independent Assortment, what is the expected phenotypic ratio in the $$F_2$$ generation of a dihybrid cross ($$AaBb 	imes AaBb) if $$both traits assort independently?

Accepted Answer

$$9:3:3:1$$

Question 10

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal Dominant

Question 11

A man with genotype $$DdEeFf$$ can produce how many genetically distinct types of gametes?

Accepted Answer

$$8$$

Question 12

In a family with four children, what is the probability that exactly two will be male and two will be female? (Assume equal probability for male and female births.)

Accepted Answer

$$6/16$$

Question 13

A pedigree shows that only males are affected and the trait is passed from father to all sons. What is the most likely mode of inheritance?

Accepted Answer

Y-linked

Question 14

If two heterozygous individuals ($$Aa) $$are crossed, what is the probability that their first two offspring will both be homozygous recessive?

Accepted Answer

$$1/16$$

Question 15

Which of the following is an example of a polymorphism in humans?

Accepted Answer

Widow's peak

Question 16

A test cross is performed between a plant of unknown genotype and a homozygous recessive plant. If all offspring display the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant

Question 17

A woman who is a carrier for an X-linked recessive disorder has children with a man who is unaffected. What is the probability that their son will be affected?

Accepted Answer

$$1/2$$

Question 18

Using the product law, what is the probability that two organisms with genotype $$AaBbCcDd$$ will produce an offspring with genotype $$AABBCCDD$$?

Accepted Answer

$$1/256$$

Question 19

Which of the following best describes Mendel's Law of Segregation?

Accepted Answer

Alleles of a gene separate during gamete formation

Question 20

A pedigree shows a trait that skips generations and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal Recessive

Genetics Study Guide: Mendelian Inheritance, Probability, and Pedigree Analysis

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