Q: A pea plant with genotype Pp is self-fertilized. What is the expected phenotypic ratio of the offspring if purple (P) is dominant to white (p)?

$$3 \text{ purple} : 1 \text{ white}$$

Question 1

Which of the following best describes Mendel’s law of segregation?

Accepted Answer

The two alleles for a heritable character separate during gamete formation, so that each gamete carries only one allele for each gene.

Question 2

A pea plant with genotype Pp is self-fertilized. What is the expected phenotypic ratio of the offspring if purple (P) is dominant to white (p)?

Accepted Answer

$$3 	ext{ purple} : 1 	ext{ white}$$

Question 3

In a testcross between a black dog of unknown genotype and a chocolate dog (bb), half the puppies are black and half are chocolate. What is the genotype of the black parent?

Accepted Answer

$$Bb$$

Question 4

Which statement about incomplete dominance is correct?

Accepted Answer

The heterozygote expresses a phenotype intermediate between the two homozygotes.

Question 5

A dihybrid cross between two plants heterozygous for both seed color (Yy) and seed shape (Rr) produces which phenotypic ratio in the F2 generation, assuming independent assortment and complete dominance?

Accepted Answer

$$9:3:3:1$$

Question 6

Which of the following best explains why a trait can disappear in one generation and reappear in the next, according to Mendel’s experiments?

Accepted Answer

Alleles retain their identity and segregate independently during gamete formation.

Question 7

If a woman wants to trace her maternal ancestry using genetic markers, which type of DNA should she analyze?

Accepted Answer

Mitochondrial DNA

Question 8

Which of the following is an example of a genotype?

Accepted Answer

$$Pp$$

Question 9

What is the physical basis for Mendel’s law of independent assortment?

Accepted Answer

The independent orientation of homologous chromosome pairs at metaphase I of meiosis

Question 10

A man claims to be a direct descendant of a famous historical figure based on a shared Y-chromosome marker. What is the best scientific interpretation of this evidence?

Accepted Answer

He shares a paternal lineage, but further evidence is needed to confirm direct descent.

Question 11

Which cross would produce only heterozygous offspring?

Accepted Answer

$$PP 	imes pp$$

Question 12

In snapdragons, red flowers ($$RR) $$crossed with white flowers ($$rr) $$produce pink flowers ($$Rr). If $$two pink flowers are crossed, what fraction of the offspring will be white?

Accepted Answer

$$1/4$$

Question 13

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes at the same loci, but may have different alleles.

Question 14

A plant with genotype $$RrYy$$ produces which types of gametes, assuming independent assortment?

Accepted Answer

$$RY, Ry, rY, ry$$

Question 15

Which of the following best describes a phenotype?

Accepted Answer

The observable traits of an organism

Question 16

If a gene is located on the X chromosome, which of the following is true?

Accepted Answer

It is a sex-linked gene and may show different inheritance patterns in males and females.

Question 17

Which of the following is a real-world example of incomplete dominance?

Accepted Answer

Pink snapdragon flowers from red and white parents

Question 18

A true-breeding plant with yellow seeds is crossed with a true-breeding plant with green seeds. All F1 offspring have yellow seeds. What does this indicate about the yellow seed allele?

Accepted Answer

It is dominant to the green seed allele.

Question 19

Which process ensures that each gamete receives only one allele for each gene?

Accepted Answer

Law of segregation during meiosis

Question 20

Why might a small sample size in a testcross fail to reveal the presence of a recessive allele?

Accepted Answer

Chance may prevent recessive offspring from appearing in a small sample.

Patterns of Inheritance: Mendelian Genetics and Beyond

Guida di studio - Domande di pratica

Study guide - Flashcard