Question 1

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are inherited from each parent and carry the same genes at the same loci, while sister chromatids are duplicated copies of a single chromosome joined at the centromere.

Question 2

During which phase of meiosis does crossing over occur, and what is the significance of this event?

Accepted Answer

Crossing over occurs during prophase I and results in genetic recombination between homologous chromosomes.

Question 3

A human cell with 46 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

Each gamete will contain 23 chromosomes.

Question 4

What is the primary cause of Down syndrome, and how is it detected in a karyotype?

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21), detected as three chromosomes in pair 21 in the karyotype.

Question 5

Which equation correctly represents the chromosome number in diploid and haploid human cells?

Accepted Answer

Diploid: $$2n = 46$$, Haploid: $$n = 23$$

Question 6

Which of the following events occurs during metaphase I of meiosis?

Accepted Answer

Pairs of homologous chromosomes line up at the metaphase plate, with one chromosome facing each pole.

Question 7

What is the function of the synaptonemal complex during meiosis?

Accepted Answer

It forms between homologous chromosomes during prophase I, facilitating synapsis and crossing over.

Question 8

Which of the following best explains why gametes are genetically unique after meiosis?

Accepted Answer

Because crossing over and independent assortment of chromosomes occur during meiosis I.

Question 9

Which of the following is NOT a difference between mitosis and meiosis?

Accepted Answer

Mitosis involves crossing over, while meiosis does not.

Question 10

During which stage of meiosis do sister chromatids finally separate?

Accepted Answer

Anaphase II

Question 11

A cell with a diploid number of 8 ($$2n = 8) $$undergoes meiosis. How many chromosomes will each daughter cell have after meiosis II?

Accepted Answer

Each daughter cell will have 4 chromosomes.

Question 12

Which of the following best describes the process of synapsis?

Accepted Answer

The pairing of homologous chromosomes during prophase I of meiosis.

Question 13

If a sperm cell contains an extra chromosome 21, what is the likely outcome after fertilization with a normal egg?

Accepted Answer

The resulting zygote will have trisomy 21, leading to Down syndrome.

Question 14

Which of the following statements about meiosis is correct?

Accepted Answer

Meiosis results in four daughter cells, each with half the chromosome number of the parent cell.

Question 15

Which phase of meiosis is most similar to mitosis, and why?

Accepted Answer

Meiosis II, because sister chromatids are separated just as in mitosis.

Question 16

What is a karyotype, and how is it used in genetics?

Accepted Answer

A karyotype is an ordered display of all chromosomes in a cell, used to detect chromosomal abnormalities.

Question 17

Which of the following best describes the alternation of meiosis and fertilization in the human life cycle?

Accepted Answer

Meiosis produces haploid gametes, and fertilization restores the diploid number.

Question 18

Which event distinguishes meiosis I from meiosis II?

Accepted Answer

Meiosis I separates homologous chromosomes, while meiosis II separates sister chromatids.

Question 19

Which of the following is a real-world consequence of errors in meiosis?

Accepted Answer

Errors in meiosis can result in chromosomal disorders such as Down syndrome due to nondisjunction.

Meiosis: Mechanisms, Phases, and Biological Significance

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