Question 1

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

Accepted Answer

Mitosis produces two diploid cells, while meiosis produces four haploid cells.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the result in terms of chromatid number?

Accepted Answer

DNA replication occurs during S phase, resulting in two chromatids per chromosome.

Question 3

A mutation causes the cohesin protein to be nonfunctional. What is the most likely consequence during mitosis?

Accepted Answer

Sister chromatids will separate prematurely, leading to chromosome missegregation.

Question 4

Which of the following equations correctly represents the change in DNA content per nucleus during the cell cycle, assuming a diploid organism with $$2n$$ chromosomes and $$C as $$the DNA content per chromosome set?

Accepted Answer

At the end of $$G_1$$: $$2C$$, after S phase: $$4C$$, after mitosis: $$2C$$

Question 5

Which checkpoint ensures that all chromosomes are properly attached to the mitotic spindle before anaphase begins?

Accepted Answer

Metaphase checkpoint

Question 6

In a human cell (2n = 46), how many chromosomes and chromatids are present at metaphase of mitosis?

Accepted Answer

46 chromosomes and 92 chromatids

Question 7

Which of the following events is unique to meiosis and does NOT occur during mitosis?

Accepted Answer

Crossing over between homologous chromosomes

Question 8

A cell is observed to have homologous chromosomes aligned side by side at the metaphase plate. Which stage is this, and what process is about to occur?

Accepted Answer

Metaphase I of meiosis; homologous chromosomes will separate

Question 9

Which structure is responsible for the movement of chromosomes during mitosis and meiosis?

Accepted Answer

Kinetochore microtubules

Question 10

A patient’s cancer cells are found to have a mutation that disables the $$G_1$$ checkpoint. What is the most likely cellular consequence?

Accepted Answer

Cells will divide uncontrollably, increasing the risk of tumor formation.

Question 11

During which substage of prophase I in meiosis does crossing over occur, and what is the visible evidence of this event?

Accepted Answer

Pachytene; chiasmata

Question 12

Which of the following best explains how independent assortment arises during meiosis?

Accepted Answer

Random orientation of homologous chromosome pairs at metaphase I

Question 13

In a diploid organism with genotype AaBb, how many genetically distinct gametes can be produced due to independent assortment alone?

Accepted Answer

4

Question 14

Which of the following statements about cytokinesis is correct?

Accepted Answer

In animal cells, a contractile ring of actin forms a cleavage furrow to divide the cell.

Question 15

A cell with a mutation in separase cannot cleave cohesin. What is the most likely result during anaphase?

Accepted Answer

Sister chromatids will fail to separate, leading to aneuploid daughter cells.

Question 16

Which region allows the X and Y chromosomes to pair during male meiosis?

Accepted Answer

Pseudoautosomal regions (PARs)

Question 17

If a cell fails to complete the S phase checkpoint, what is the most likely outcome?

Accepted Answer

The cell will not proceed to mitosis until DNA replication is complete and errors are repaired.

Question 18

Which of the following best describes the mechanical basis for Mendel’s law of segregation?

Accepted Answer

Separation of homologous chromosomes during anaphase I of meiosis

Question 19

A researcher observes a cell with four visible chromatids per homologous pair, recombination nodules, and a synaptonemal complex. Which stage is this cell in?

Accepted Answer

Pachytene of prophase I in meiosis

Cell Division and Chromosome Heredity: Mitosis and Meiosis

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