Question 1

Which of the following best describes the relationship between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are pairs of chromosomes with the same genes but possibly different alleles, while sister chromatids are identical copies of a single chromosome formed during DNA replication.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the result of this process?

Accepted Answer

DNA replication occurs during the S phase, resulting in each chromosome consisting of two sister chromatids.

Question 3

A human skin cell contains 46 chromosomes. After mitosis and cytokinesis, how many chromosomes will each daughter cell contain, and what is the ploidy of these cells?

Accepted Answer

Each daughter cell will have 46 chromosomes and be diploid.

Question 4

Which of the following correctly describes the difference between autosomes and sex chromosomes in humans?

Accepted Answer

Autosomes are chromosome pairs 1-22, while sex chromosomes are the X and Y chromosomes.

Question 5

Which of the following sequences correctly represents the order of phases in mitosis?

Accepted Answer

Prophase → Metaphase → Anaphase → Telophase

Question 6

A scientist observes a cell with chromosomes aligned at the center of the cell. Which phase of mitosis is this cell in, and what is the significance of this arrangement?

Accepted Answer

The cell is in metaphase, and this arrangement ensures that each daughter cell will receive one copy of each chromosome.

Question 7

Which of the following best explains why meiosis, but not mitosis, is essential for sexual reproduction?

Accepted Answer

Meiosis reduces the chromosome number by half, creating haploid gametes that can fuse during fertilization to restore the diploid number.

Question 8

A mutation occurs that prevents cytokinesis from happening after mitosis in a plant cell. What would be the result?

Accepted Answer

The cell would have two nuclei and be larger than normal.

Question 9

Which of the following is a correct example of a diploid cell and a haploid cell in humans?

Accepted Answer

A skin cell is diploid, and an egg cell is haploid.

Question 10

During fertilization, which of the following events occurs?

Accepted Answer

Two haploid gametes fuse to form a diploid zygote.

Question 11

A cell spends most of its life in which phase of the cell cycle, and what major event occurs during this phase?

Accepted Answer

Interphase; the cell grows and DNA is replicated.

Question 12

If a cell with 8 chromosomes undergoes mitosis, how many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

$$8$$

Question 13

Which of the following best describes the role of the S phase in the cell cycle?

Accepted Answer

It is the phase where DNA is synthesized, resulting in the duplication of chromosomes.

Question 14

A patient is diagnosed with a genetic disorder caused by an abnormal number of sex chromosomes. Which chromosomes are most likely involved?

Accepted Answer

X and Y chromosomes

Question 15

Which of the following events distinguishes anaphase from other stages of mitosis?

Accepted Answer

Sister chromatids are separated and pulled toward opposite poles.

Question 16

A researcher is studying a cell that has just completed telophase and cytokinesis. Which of the following best describes the state of the two resulting cells?

Accepted Answer

Each cell has a single nucleus and a complete set of chromosomes identical to the original cell.

Question 17

Which of the following is true regarding the ploidy of gametes and zygotes in humans?

Accepted Answer

Gametes are haploid ($$n$$), and zygotes are diploid ($$2n).$$

Question 18

A cell is observed to have chromosomes that are decondensing and a nuclear envelope that is reforming. Which phase of mitosis is this cell in?

Accepted Answer

Telophase

Question 19

Which of the following best explains why cancer cells often have abnormal numbers of chromosomes?

Accepted Answer

They undergo uncontrolled cell division, leading to errors in chromosome segregation during mitosis.

Question 20

A biologist is studying the reproductive life cycle of a flowering plant. Which of the following correctly describes the role of fertilization in this cycle?

Accepted Answer

Fertilization restores the diploid number by combining two haploid gametes to form a zygote.

Cell Cycle and Cellular Reproduction: Key Concepts and Vocabulary

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