Question 1

Which of the following best describes the main purpose of meiosis in sexually reproducing organisms?

Accepted Answer

To reduce the chromosome number by half, creating haploid gametes

Question 2

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes

Question 3

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

Accepted Answer

23

Question 4

Which equation correctly represents the possible combinations of chromosomes due to independent assortment in humans?

Accepted Answer

$$2^{23}$$

Question 5

What is the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are inherited from each parent, while sister chromatids are identical copies formed after DNA replication

Question 6

Which event is unique to meiosis and does NOT occur in mitosis?

Accepted Answer

Synapsis and crossing over of homologous chromosomes

Question 7

If a mutation prevents the formation of chiasmata during meiosis, which process would be directly affected?

Accepted Answer

Crossing over

Question 8

Which of the following best explains why offspring from sexual reproduction are genetically unique?

Accepted Answer

Because meiosis and fertilization introduce variation through independent assortment, crossing over, and random fertilization

Question 9

During metaphase I of meiosis, what is the arrangement of chromosomes?

Accepted Answer

Homologous pairs (tetrads) line up at the metaphase plate

Question 10

A plant species has a diploid number of 18. How many chromosomes will be found in each gamete after meiosis?

Accepted Answer

9

Question 11

Which mechanism contributes most directly to the genetic diversity seen in siblings from the same parents?

Accepted Answer

Crossing over during prophase I of meiosis

Question 12

What is the result of meiosis II in terms of chromosome number and genetic composition?

Accepted Answer

Four haploid cells, each genetically distinct

Question 13

Which of the following statements about fertilization is correct?

Accepted Answer

Fertilization restores the diploid chromosome number in the zygote

Question 14

If a human egg cell contains an X chromosome, what are the possible sex chromosome combinations in the resulting zygote after fertilization?

Accepted Answer

XX or XY

Question 15

Which of the following best describes the process of independent assortment?

Accepted Answer

Each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of other pairs

Question 16

A mutation causes a failure in cytokinesis after meiosis II. What would be the result?

Accepted Answer

One cell with four haploid nuclei

Question 17

Which of the following is NOT a mechanism that contributes to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of chromosomes during mitosis

Question 18

In a medical scenario, a patient is found to have an abnormal number of chromosomes in their somatic cells. Which process most likely failed during gamete formation?

Accepted Answer

Meiosis

Question 19

Which of the following best explains why asexual reproduction produces offspring that are genetically identical to the parent?

Accepted Answer

Asexual reproduction involves mitosis, which conserves chromosome number and genetic information

Question 20

A scientist observes a cell with two sets of chromosomes, each consisting of two sister chromatids. Which stage of meiosis is this cell most likely in?

Accepted Answer

After interphase, before meiosis I

Meiosis and Sexual Life Cycles: Study Notes

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