Question 1

Which of the following best describes the difference between somatic cells and gametes in humans?

Accepted Answer

Somatic cells are diploid (2n) and gametes are haploid (n).

Question 2

A human karyotype shows 46 chromosomes. How many chromosomes are present in a human sperm cell?

Accepted Answer

$$23$$

Question 3

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 4

What is the evolutionary significance of genetic variation produced by sexual reproduction?

Accepted Answer

It allows populations to adapt to changing environments through natural selection.

Question 5

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during S phase

Question 6

If a species has a diploid number of $$2n = 8$$, how many possible combinations of chromosomes can be produced in its gametes due to independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 7

Which protein complex is responsible for holding sister chromatids together during meiosis, and what is its fate during Anaphase I?

Accepted Answer

Rec8 cohesin; it is protected at the centromere by SGO during Anaphase I

Question 8

Which of the following best describes the outcome of meiosis II?

Accepted Answer

Separation of sister chromatids into four genetically unique haploid cells

Question 9

A mutation occurs in the SGO gene, causing it to be nonfunctional. What is the most likely consequence during meiosis?

Accepted Answer

Sister chromatids will separate prematurely during Anaphase I.

Question 10

Which of the following statements about homologous chromosomes is TRUE?

Accepted Answer

They carry genes for the same traits at the same loci, but may have different alleles.

Question 11

Which of the following is a key difference between mitosis and meiosis?

Accepted Answer

Mitosis results in genetically identical cells, while meiosis results in genetically diverse cells.

Question 12

Which event during meiosis is responsible for the formation of recombinant chromosomes?

Accepted Answer

Crossing over during Prophase I

Question 13

A cell with 12 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$6$$

Question 14

Which of the following best explains why offspring produced by sexual reproduction are genetically different from their parents?

Accepted Answer

Independent assortment, crossing over, and random fertilization introduce genetic variation.

Question 15

Which of the following is NOT a characteristic of asexual reproduction?

Accepted Answer

Fusion of gametes is required.

Question 16

What is the probability that two non-twin siblings are genetically identical, considering only independent assortment and random fertilization (not crossing over)?

Accepted Answer

$$1:70$$ 	ext{ trillion}

Question 17

Which of the following best defines an allele?

Accepted Answer

A different version of the same gene.

Question 18

Which stage of meiosis is characterized by the alignment of homologous chromosome pairs at the metaphase plate?

Accepted Answer

Metaphase I

Question 19

Which of the following statements about autosomes and sex chromosomes is correct?

Accepted Answer

Humans have 22 pairs of autosomes and one pair of sex chromosomes.

Question 20

Which of the following must occur during interphase prior to meiosis?

Accepted Answer

DNA replication, resulting in duplicated chromosomes.

Meiosis and Sexual Life Cycles: Mechanisms and Evolutionary Significance

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