Question 1

Which of the following best describes the outcome of mitosis in a typical human somatic cell?

Accepted Answer

Two daughter cells, each with $$2n=46$$ chromosomes

Question 2

During sexual reproduction in humans, what is the result of fertilization at the chromosomal level?

Accepted Answer

A diploid zygote is formed with $$2n=46$$ chromosomes

Question 3

Which process is responsible for reducing the chromosome number from diploid to haploid in sexually reproducing organisms?

Accepted Answer

Meiosis

Question 4

A horticulturist successfully breeds an orchid with a unique combination of traits. To produce more plants with these traits, which method should she use?

Accepted Answer

Cloning the orchid

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

In humans, how many possible combinations of chromosomes can result from independent assortment alone during gamete formation?

Accepted Answer

$$2^{23}$$, or about 8.4 million

Question 7

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

Accepted Answer

Alignment of homologous pairs at the metaphase plate

Question 8

A cell with $$2n=46$$ chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$n=23$$

Question 9

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

Accepted Answer

Genetic variation arises from independent assortment, crossing over, and random fertilization

Question 10

During prophase I of meiosis, what is the significance of crossing over?

Accepted Answer

It produces recombinant chromosomes, increasing genetic diversity

Question 11

Which statement correctly compares mitosis and meiosis?

Accepted Answer

Mitosis conserves chromosome number; meiosis reduces chromosome number

Question 12

In the alternation of generations life cycle found in plants, which process produces haploid spores?

Accepted Answer

Meiosis in the sporophyte

Question 13

If a diploid cell with $$2n=8$$ chromosomes undergoes meiosis, how many different combinations of chromosomes can be produced in its gametes due to independent assortment?

Accepted Answer

$$2^4 = 16$

Question 14

Which of the following is a direct result of random fertilization in humans?

Accepted Answer

Each zygote has a unique combination of alleles, with about $$70$$ trillion possible combinations

Question 15

What is the role of homologous chromosomes during meiosis I?

Accepted Answer

They separate into different cells, reducing the chromosome number by half

Question 16

Which of the following best describes a karyotype?

Accepted Answer

A display of chromosome pairs arranged by size and shape

Question 17

In fungi and some protists, which stage is the only diploid stage in the life cycle?

Accepted Answer

The single-celled zygote

Question 18

Which of the following is true about sister chromatids?

Accepted Answer

They are identical copies of a chromosome joined at the centromere

Question 19

If crossing over did NOT occur during meiosis, what would be the most likely effect on gamete formation?

Accepted Answer

Gametes would have reduced genetic variation

Question 20

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

Accepted Answer

Humans have 22 pairs of autosomes and 1 pair of sex chromosomes

The Cell Cycle, Mitosis, and Meiosis: Key Concepts and Mechanisms

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