Question 1

Which process restores the diploid chromosome number in the sexual life cycle, as shown in the diagram of fertilization?

Accepted Answer

Fertilization

Question 2

During which phase of meiosis does crossing over occur, as illustrated in the site of crossover diagram?

Accepted Answer

Prophase I

Question 3

What is the result of independent assortment during metaphase I, as shown in the diagram with two equally probable arrangements?

Accepted Answer

Gametes have random combinations of maternal and paternal chromosomes

Question 4

If a diploid snail species has $$2n = 34$$ chromosomes, how many chromosomes will each gamete have after meiosis?

Accepted Answer

$$17$$

Question 5

Which event distinguishes Anaphase I from Anaphase II in meiosis?

Accepted Answer

Homologous chromosomes separate in Anaphase I; sister chromatids separate in Anaphase II

Question 6

Why are the four daughter cells produced by meiosis non-identical?

Accepted Answer

Due to crossing over and independent assortment

Question 7

A karyotype shows three copies of chromosome 21. What is the most likely cause of this genetic abnormality?

Accepted Answer

Nondisjunction during meiosis

Question 8

If nondisjunction occurs during Meiosis I, what is the result for the gametes?

Accepted Answer

Half will have an extra chromosome, and half will lack one

Question 9

Why does advanced maternal age increase the risk of nondisjunction?

Accepted Answer

Older eggs are more likely to experience errors in chromosome separation

Question 10

If an egg with 24 chromosomes is fertilized by a normal sperm, what will be the chromosome number in the resulting zygote?

Accepted Answer

$$47$$

Question 11

Which mechanism does NOT contribute to genetic variation during meiosis?

Accepted Answer

Cytokinesis

Question 12

What is the main function of mitosis in the sexual life cycle?

Accepted Answer

To produce genetically identical somatic cells for growth and repair

Question 13

Which statement best explains why siblings are not genetically identical?

Accepted Answer

Random fertilization and independent assortment create unique combinations of alleles

Question 14

If a population experienced a mutation that eliminated crossing over, which outcome would you predict?

Accepted Answer

Genetic diversity would decrease

Question 15

Which equation represents the chromosome number in a diploid cell after DNA replication?

Accepted Answer

$$4n$$

Question 16

Why doesn’t crossing over happen in mitosis?

Accepted Answer

Homologous chromosomes do not pair up during mitosis

Question 17

How does meiosis ensure chromosome number is halved in gametes?

Accepted Answer

By separating homologous chromosomes in Meiosis I and sister chromatids in Meiosis II

Question 18

If each human gamete can produce $$8 	imes 10^6$ combinations due to independent assortment, how does random fertilization affect total possible zygotic combinations?

Accepted Answer

Multiplies combinations between gametes from both parents

Question 19

Which feature is unique to meiosis compared to mitosis?

Accepted Answer

Crossing over occurs

Question 20

Evaluate the statement: 'Meiosis and mitosis are identical except meiosis produces half the chromosomes.'

Accepted Answer

Incorrect, because meiosis includes two divisions and promotes genetic diversity

Study Guide: Meiosis, Genetic Diversity, and Chromosome Behavior

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