Q: If a cell spends 15 minutes in the M phase and the total cell cycle is 20 hours, what percentage of the cell cycle is spent in M phase? (Round to the nearest tenth)

$$\frac{15}{20 \times 60} \times 100 = 1.25\%$$

Question 1

Which of the following best describes the main event that occurs during the S phase of the cell cycle?

Accepted Answer

DNA is replicated, resulting in each chromosome consisting of two sister chromatids.

Question 2

A cell with 12 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis is complete?

Accepted Answer

12

Question 3

During which phase of mitosis do sister chromatids separate and move toward opposite poles of the cell?

Accepted Answer

Anaphase

Question 4

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Question 5

A human somatic cell contains 46 chromosomes. After meiosis II, how many chromosomes will each gamete contain?

Accepted Answer

23

Question 6

Which process during meiosis increases genetic variation by exchanging genetic material between homologous chromosomes?

Accepted Answer

Crossing over

Question 7

If a cell spends 15 minutes in the M phase and the total cell cycle is 20 hours, what percentage of the cell cycle is spent in M phase? (Round to the nearest tenth)

Accepted Answer

$$\frac{15}{20 	imes 60} 	imes 100 = 1.25\%$$

Question 8

Which of the following best explains why cytokinesis differs between plant and animal cells?

Accepted Answer

Animal cells form a cleavage furrow, while plant cells build a cell plate from vesicles derived from the Golgi apparatus.

Question 9

Down syndrome is caused by trisomy 21. Which meiotic error most likely leads to this condition?

Accepted Answer

Nondisjunction during anaphase I or II

Question 10

Which of the following is true about the difference between mitosis and meiosis?

Accepted Answer

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

Question 11

A cell is measured at two points in the cell cycle. At one point, the cell has 4.2 units of DNA, and at another, it has 2.1 units. Which phase is the cell most likely in when it has 4.2 units of DNA?

Accepted Answer

G2 phase

Question 12

Which of the following best describes the role of growth factors in the cell cycle?

Accepted Answer

They are external signals that can stimulate a cell to divide.

Question 13

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

Accepted Answer

Homologous chromosomes pair up and crossing over occurs.

Question 14

If a diploid cell with genotype AaBb undergoes meiosis, what is the probability that a gamete will receive the AB combination, assuming independent assortment?

Accepted Answer

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

Question 15

Which of the following best explains why the number of possible gamete combinations in humans is so large?

Accepted Answer

Crossing over and independent assortment during meiosis create many possible combinations of chromosomes.

Question 16

Which of the following is a correct statement about the difference between haploid and diploid cells?

Accepted Answer

Diploid cells have two sets of chromosomes, while haploid cells have one.

Question 17

Which of the following best describes an oncogene?

Accepted Answer

A mutated gene that can cause uncontrolled cell division and lead to cancer.

Question 18

During which stage of mitosis do chromosomes align at the center of the cell?

Accepted Answer

Metaphase

Question 19

Which of the following is a direct result of independent assortment during meiosis?

Accepted Answer

Each gamete receives a random mix of maternal and paternal chromosomes.

Question 20

A cell is observed under a microscope, and chromosomes are found lined up in the middle of the cell, attached to spindle fibers. Which stage is this cell in?

Accepted Answer

Metaphase

Cell Cycle, Mitosis, and Meiosis: Study Notes for General Biology

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