Question 1

Which of the following best describes the difference between mitosis and meiosis in terms of chromosome number in the resulting daughter cells?

Accepted Answer

Mitosis produces daughter cells with the same chromosome number as the parent cell, while meiosis produces daughter cells with half the chromosome number.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the significance of this phase for mitosis?

Accepted Answer

DNA replication occurs during the S phase, allowing each chromosome to consist of two sister chromatids for proper segregation during mitosis.

Question 3

A biologist observes a cell with 8 chromosomes undergoing mitosis. How many chromosomes will each daughter cell have after cytokinesis, and why?

Accepted Answer

Each daughter cell will have 8 chromosomes because mitosis produces genetically identical cells.

Question 4

Which of the following best explains the importance of crossing over during meiosis?

Accepted Answer

Crossing over increases genetic variation by exchanging genetic material between homologous chromosomes.

Question 5

A species of plant has a diploid number of 12 chromosomes. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

6 chromosomes

Question 6

Which of the following scenarios best illustrates the concept of a haploid-dominant life cycle?

Accepted Answer

A multicellular organism spends most of its life as a haploid, with the diploid stage limited to a single zygote cell.

Question 7

In a human karyotype, which of the following would indicate a male individual?

Accepted Answer

Presence of one X and one Y chromosome

Question 8

A pedigree shows a trait that appears in every generation and affects both males and females equally. Which mode of inheritance is most likely?

Accepted Answer

Autosomal dominant

Question 9

If two heterozygous parents (Aa) for a single gene have children, what is the expected genotypic ratio among their offspring according to a Punnett square?

Accepted Answer

$$1 \mathrm{AA} : 2 \mathrm{Aa} : 1 \mathrm{aa}$$

Question 10

A geneticist is studying a population where the allele for brown eyes (B) is dominant over blue eyes (b). If the frequency of the b allele is 0.4, what is the expected frequency of heterozygotes in the population according to Hardy-Weinberg equilibrium?

Accepted Answer

$$0.48$$

Question 11

Which of the following best explains why cancer can result from errors in the cell cycle?

Accepted Answer

Cancer results when cells lose control over the checkpoints in the cell cycle, leading to uncontrolled cell division.

Question 12

Which of the following is a real-world example of a sex-determination system that is not based on the XY system found in humans?

Accepted Answer

Birds, where females are ZW and males are ZZ

Question 13

A couple has a child with a rare autosomal recessive disorder. Neither parent shows symptoms. What is the probability that their next child will also have the disorder?

Accepted Answer

$$1/4$$

Question 14

Which of the following best describes the process and significance of independent assortment during meiosis?

Accepted Answer

Independent assortment occurs during meiosis I and increases genetic variation by randomly distributing maternal and paternal chromosomes to gametes.

Question 15

A scientist is analyzing a pedigree for a rare X-linked recessive disorder. Which pattern would most likely be observed?

Accepted Answer

The disorder appears more frequently in males, and affected males often have carrier mothers.

Question 16

Which of the following best explains the concept of a gene pathway as it relates to sex determination in mammals?

Accepted Answer

A gene pathway is a series of genes that interact to determine whether an individual develops as male or female, such as the SRY gene triggering male development.

Question 17

In a dihybrid cross between two individuals heterozygous for both traits (AaBb x AaBb), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$9:3:3:1$$

Question 18

A patient is diagnosed with a genetic disorder caused by a dominant allele. If one parent is heterozygous for the disorder and the other is homozygous recessive, what is the probability that their child will inherit the disorder?

Accepted Answer

$$1/2$$

Question 19

Which of the following best describes the role of checkpoints in the cell cycle?

Accepted Answer

Checkpoints monitor and regulate the progression of the cell cycle, ensuring that critical processes such as DNA replication and chromosome alignment are completed correctly.

Question 20

A researcher is studying a population of butterflies where the gene for wing color is sex-linked and located on the Z chromosome. If a female butterfly (ZW) with white wings mates with a male (ZZ) with black wings, and black is dominant, what proportion of female offspring will have black wings?

Accepted Answer

All female offspring will have black wings.

Study Guide: Mitosis, Meiosis, Cell Cycle, and Sex Determination

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