Question 1

Which of the following best describes the difference between mitosis and meiosis in terms of their outcomes?

Accepted Answer

Mitosis produces two genetically identical somatic cells, while meiosis produces four genetically unique gametes.

Question 2

Which experiment provided the first strong evidence that DNA is the genetic material, and what was the key finding?

Accepted Answer

Avery, MacLeod, and McCarty's experiment; they demonstrated that DNA, not protein or RNA, was responsible for transformation.

Question 3

A woman who is heterozygous for an X-linked recessive 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 4

In a dihybrid cross between two heterozygotes (AaBb x AaBb), what is the expected phenotypic ratio if the genes assort independently?

Accepted Answer

9:3:3:1

Question 5

Which of the following statements about recombination frequency is correct?

Accepted Answer

A recombination frequency of 50% indicates that two genes are on different chromosomes or far apart on the same chromosome.

Question 6

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 7

Which of the following best describes the difference between F+, F-, Hfr, and F’ bacterial cells?

Accepted Answer

Hfr cells have the F plasmid integrated into the chromosome, while F+ cells have the F plasmid as a separate plasmid.

Question 8

A geneticist performs a complementation test between two mutants with the same phenotype. The offspring display the wild-type phenotype. What does this indicate?

Accepted Answer

The mutations are in different genes.

Question 9

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red-flowered and white-flowered snapdragons produces pink-flowered offspring.

Question 10

If a gene shows variable expressivity, which of the following is true?

Accepted Answer

Individuals with the same genotype may show different degrees of the phenotype.

Question 11

Which of the following best explains why linked genes do not follow Mendel’s law of independent assortment?

Accepted Answer

They are located close together on the same chromosome and tend to be inherited together.

Question 12

A couple has a child with cystic fibrosis, an autosomal recessive disorder. Neither parent has the disease. What is the probability that their next child will also have cystic fibrosis?

Accepted Answer

$$\frac{1}{4}$$

Question 13

Which of the following is true about the structure of double-stranded DNA?

Accepted Answer

The two strands are antiparallel and held together by hydrogen bonds between complementary bases.

Question 14

In a three-point test cross, the order of three genes is determined by analyzing the frequency of recombinant offspring. Which class of offspring is the least frequent?

Accepted Answer

Double crossovers

Question 15

Which of the following mechanisms is responsible for the transfer of DNA from one bacterium to another via a bacteriophage?

Accepted Answer

Transduction

Question 16

A researcher observes that a certain trait is only expressed in males, even though both sexes have the same genotype. This is an example of:

Accepted Answer

Sex-limited inheritance

Question 17

Which of the following best describes the law of segregation?

Accepted Answer

Each individual has two alleles for each gene, which separate during gamete formation.

Question 18

A chi-square test is used in genetics to:

Accepted Answer

Determine if observed data fit expected Mendelian ratios.

Question 19

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene mutation causes multiple symptoms in Marfan syndrome.

Question 20

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

Accepted Answer

Prophase I; it increases genetic diversity by exchanging genetic material between homologous chromosomes.

Genetics Exam 1 Study Guide – Key Concepts and Review Topics (Sanders 3rd Edition)

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