Question 1

Which of the following best explains why sexual reproduction leads to greater genetic variation in offspring compared to asexual reproduction?

Accepted Answer

Sexual reproduction involves the fusion of gametes, each with unique combinations of alleles due to independent assortment and crossing over.

Question 2

A human cell with 46 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain, and what is this condition called?

Accepted Answer

23 chromosomes; haploid

Question 3

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation among gametes

Question 4

If a pea plant with genotype $YyRr$ (yellow, round seeds) is self-crossed, what is the probability of obtaining an offspring with genotype $yyrr$ (green, wrinkled seeds)?

Accepted Answer

$\frac{1}{16}$

Question 5

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 6

A woman who is a carrier for a recessive X-linked disorder marries a man who does not have the disorder. What is the probability that their son will have the disorder?

Accepted Answer

$\frac{1}{2}$

Question 7

Which of the following best describes the Law of Independent Assortment?

Accepted Answer

Each pair of alleles segregates independently of any other pair during gamete formation.

Question 8

A child is born with Down syndrome (Trisomy 21). Which chromosomal event most likely caused this condition?

Accepted Answer

Nondisjunction during meiosis

Question 9

Which of the following scenarios illustrates codominance?

Accepted Answer

A person with type AB blood expressing both A and B antigens equally.

Question 10

If a genetic disorder is caused by a dominant allele, what is the probability that a heterozygous individual will pass the disorder to their child, assuming the other parent is homozygous recessive?

Accepted Answer

$\frac{1}{2}$

Question 11

Which of the following best explains why linked genes do not always show perfect linkage in offspring?

Accepted Answer

Crossing over during meiosis can separate linked genes, resulting in recombinant types.

Question 12

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 13

Which of the following is a consequence of nondisjunction during meiosis?

Accepted Answer

A gamete with an abnormal number of chromosomes

Question 14

A man with normal vision (XY) and a woman who is a carrier for color blindness (X$^N$X$^n$) have a daughter. What is the probability that the daughter will be color blind?

Accepted Answer

$0$

Question 15

Which of the following best describes the difference between aneuploidy and polyploidy?

Accepted Answer

Aneuploidy is the presence of an abnormal number of a particular chromosome, while polyploidy is the presence of more than two complete sets of chromosomes.

Question 16

Which of the following is an example of a genetic disorder caused by a structurally altered chromosome?

Accepted Answer

Cri du chat syndrome

Question 17

A test cross is performed between a pea plant with an 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 18

Which of the following best explains why mitochondrial inheritance does not follow Mendelian patterns?

Accepted Answer

Mitochondria are inherited only from the mother, so traits encoded by mitochondrial genes are passed maternally.

Question 19

Which of the following is a real-world example of a disorder caused by a recessive allele that provides an evolutionary advantage in heterozygotes?

Accepted Answer

Sickle-cell disease

Question 20

If two genes are located close together on the same chromosome, which of the following is most likely true?

Accepted Answer

They tend to be inherited together due to genetic linkage.

Study Notes: Mendelian Genetics, Chromosomal Inheritance, and Meiosis

Study Guide - Practice Questions

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