Question 1

Which of the following best describes the difference between sexual and asexual reproduction in terms of genetic diversity?

Accepted Answer

Sexual reproduction combines genetic material from two parents, resulting in genetically unique offspring, while asexual reproduction produces genetically identical clones.

Question 2

During which phase of meiosis does homologous recombination (crossing over) most commonly occur?

Accepted Answer

Prophase I

Question 3

A human cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

$$46$$

Question 4

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

Accepted Answer

Pairing and separation of homologous chromosomes

Question 5

Independent assortment during meiosis contributes to genetic variation. If an organism has $$n$$ pairs of chromosomes, how many possible combinations of chromosomes can be produced in its gametes due to independent assortment alone?

Accepted Answer

$$2^n$$

Question 6

Down syndrome is most commonly caused by which chromosomal abnormality?

Accepted Answer

Three complete copies of chromosome 21 (trisomy 21)

Question 7

Which process is responsible for the formation of gametes in humans?

Accepted Answer

Meiosis

Question 8

If nondisjunction occurs during meiosis I in a human oocyte, what is the most likely chromosomal outcome in the resulting gametes?

Accepted Answer

Half the gametes will have one extra chromosome, and half will have one less.

Question 9

Which of the following best explains why crossing over during meiosis increases genetic diversity?

Accepted Answer

It results in the exchange of equivalent sections between homologous chromosomes, creating new allele combinations.

Question 10

A karyotype is most useful for detecting which of the following genetic abnormalities?

Accepted Answer

Chromosomal number abnormalities such as trisomy 21

Question 11

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Question 12

If a diploid cell (2n = 40) undergoes meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

$$20$$

Question 13

Which of the following is a direct consequence of nondisjunction during meiosis?

Accepted Answer

Production of gametes with abnormal chromosome numbers

Question 14

Why is metaphase the best stage to collect cells for karyotyping?

Accepted Answer

Chromosomes are fully condensed and aligned, making them easier to visualize and count.

Question 15

Which of the following best describes the ploidy of a zygote formed after fertilization in humans?

Accepted Answer

Diploid ($$2n)$$

Question 16

A woman aged 40 is pregnant. Based on the provided chart, what is true about her risk of having a child with Down syndrome compared to a woman aged 25?

Accepted Answer

Her risk is significantly higher than that of a 25-year-old woman.

Question 17

Which of the following is NOT a possible outcome of homologous recombination during meiosis?

Accepted Answer

Production of identical gametes

Question 18

Which of the following best explains why diploid organisms need specialized sex cells (gametes)?

Accepted Answer

To allow traits to be inherited from two parents, maintaining the species' chromosome number.

Question 19

Which of the following statements about the role of the clinic in detecting Down syndrome is most accurate based on the case study?

Accepted Answer

The clinic is only liable if it failed to follow established guidelines for testing.

Meiosis, Sexual Cycles, and Chromosomal Inheritance

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