Question 1

Which of the following best explains why sexual reproduction results in greater genetic variation than asexual reproduction?

Accepted Answer

Sexual reproduction combines genetic material from two parents and includes processes such as crossing over and independent assortment.

Question 2

A researcher observes a cell with two identical sister chromatids attached at a centromere. During which phase of the cell cycle did DNA replication occur?

Accepted Answer

S phase

Question 3

Which of the following events occurs during prophase I of meiosis but not during mitosis?

Accepted Answer

Crossing over between homologous chromosomes at the chiasma

Question 4

A cell undergoes mitosis but fails to complete cytokinesis. What is the most likely result?

Accepted Answer

A single cell with two nuclei

Question 5

Which of the following best describes the difference between benign and malignant tumors?

Accepted Answer

Benign tumors do not invade surrounding tissues, while malignant tumors can invade and spread to other parts of the body.

Question 6

A human karyotype reveals three copies of chromosome 21. Which process most likely caused this condition?

Accepted Answer

Nondisjunction during meiosis

Question 7

In Mendel’s experiments with pea plants, what was the phenotypic ratio observed in the F2 generation of a dihybrid cross?

Accepted Answer

$$9:3:3:1$$

Question 8

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

Accepted Answer

$$0.5$$

Question 9

Which of the following best explains why dominant genetic disorders are less common than recessive ones?

Accepted Answer

Individuals with dominant disorders are more likely to be affected and less likely to reproduce, reducing the frequency of the allele.

Question 10

A plant with genotype $$RrYy is $$crossed with a plant with genotype $$rryy. $$What is the probability that an offspring will have the genotype $$rrYy$$? (Assume independent assortment.)

Accepted Answer

$$0.25$$

Question 11

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 12

Which statement best describes the law of independent assortment?

Accepted Answer

Alleles for different genes segregate independently during gamete formation.

Question 13

A couple has two children. What is the probability that both are girls? (Use the rule of multiplication.)

Accepted Answer

$$0.25$$

Question 14

Which of the following best explains why recessive X-linked traits are more common in males than females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will cause the trait.

Question 15

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene causes multiple symptoms in sickle cell disease, such as anemia and organ damage.

Question 16

Which process is responsible for the separation of homologous chromosomes?

Accepted Answer

Anaphase I of meiosis

Question 17

A woman with genotype $$Aa$$ for a trait and a man with genotype $$aa$$ have a child. What is the probability that the child will be homozygous recessive? (Use the rule of multiplication.)

Accepted Answer

$$0.5$$

Question 18

Which of the following best describes the chromosome theory of inheritance?

Accepted Answer

Genes are located on chromosomes, and the behavior of chromosomes during meiosis accounts for inheritance patterns.

Question 19

Which of the following is a key difference between cell division in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes use binary fission, which does not involve mitotic spindles, while eukaryotes use mitosis and meiosis.

Question 20

Which of the following best explains why the environment can affect phenotype?

Accepted Answer

Environmental factors can influence gene expression, resulting in different phenotypes from the same genotype.

Cellular Reproduction and Patterns of Inheritance: Study Guide for BIO 110 Exam 4

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