Question 1

Which of the following best describes the relationship between alleles, genes, chromosomes, genotypes, and phenotypes?

Accepted Answer

Alleles are different forms of a gene; genes are segments of DNA located on chromosomes; genotype is the genetic makeup (combination of alleles); phenotype is the observable trait resulting from the genotype.

Question 2

A pea plant with genotype $$Aa is $$crossed with another plant with genotype $$aa. $$What is the probability that the offspring will display the dominant phenotype?

Accepted Answer

$$0.5$$

Question 3

Which statement correctly explains Mendel's Law of Segregation?

Accepted Answer

Each individual has two alleles for each gene, which separate during gamete formation so that each gamete receives only one allele.

Question 4

In a monohybrid cross between two heterozygous individuals ($$Aa 	imes Aa$$), what is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:2:1 (AA$$:Aa:aa)

Question 5

Which of the following is an example of a homozygous genotype?

Accepted Answer

$$AA$$

Question 6

A woman who is a carrier for an X-linked recessive disorder (genotype $$X^N X^n) $$and a man who is unaffected ($$X^N Y) $$have a son. What is the probability that their son will have the disorder?

Accepted Answer

$$0.5$$

Question 7

Which of the following best explains why males are more likely to express X-linked recessive traits than females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele on the X chromosome will result in the trait being expressed.

Question 8

Which process allows eukaryotic cells to regulate gene expression by adding acetyl groups to histone proteins?

Accepted Answer

Histone acetylation

Question 9

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 10

Which of the following is a correct statement about epigenetics?

Accepted Answer

Epigenetic changes can alter gene expression without changing the DNA sequence.

Question 11

Which of the following is an example of a Y-linked trait?

Accepted Answer

A gene that causes male infertility and is only passed from father to son

Question 12

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

Accepted Answer

Genes for different traits are sorted into gametes independently of one another.

Question 13

A geneticist is studying a population of beetles. Over several generations, the frequency of a particular allele increases due to the beetles with that allele surviving better in their environment. Which process is most directly responsible for this change?

Accepted Answer

Natural selection

Question 14

Which of the following is a disadvantage for prokaryotes grouping related metabolic genes into a single operon?

Accepted Answer

If one promoter is mutated, all genes in the operon may fail to be expressed.

Question 15

In a dihybrid cross between two individuals heterozygous for both traits ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio among the offspring if both traits show complete dominance?

Accepted Answer

$$9:3:3:1$$

Question 16

Which of the following mechanisms can silence gene expression in eukaryotic cells?

Accepted Answer

DNA methylation

Question 17

A woman who is heterozygous for a recessive autosomal disorder ($$Aa) $$and a man who is homozygous dominant ($$AA) $$have a child. What is the probability that the child will be a carrier?

Accepted Answer

$$0.5$$

Question 18

Which of the following best describes speciation?

Accepted Answer

The formation of a new species when populations become reproductively isolated.

Question 19

Which of the following is a real-world example of an X-linked recessive disorder?

Accepted Answer

Hemophilia A

Question 20

Which of the following statements about gene regulation in prokaryotes is correct?

Accepted Answer

Prokaryotes primarily regulate gene expression at the level of transcription.

Genetics, Gene Regulation, and Speciation: Study Notes for General Biology

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