Question 1

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Because each sibling receives a random combination of alleles due to independent assortment and crossing over during meiosis.

Question 2

A human somatic cell contains 46 chromosomes. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

$$23$$

Question 3

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

Accepted Answer

Meiosis

Question 4

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes.

Question 5

If an organism has a diploid number of $$2n = 8$$, how many possible chromosome combinations can be produced in its gametes by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 6

Which of the following statements about asexual reproduction is correct?

Accepted Answer

Asexual reproduction produces offspring that are genetically identical to the parent.

Question 7

What is the result of fertilization in humans?

Accepted Answer

A diploid zygote with $$2n = 46$$ chromosomes.

Question 8

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

Accepted Answer

Pairing of homologous chromosomes and crossing over.

Question 9

A mutation occurs in a gene that codes for eye color. What is the most likely result of this mutation?

Accepted Answer

A new allele for eye color is created, potentially leading to a new trait.

Question 10

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

Accepted Answer

Homologous chromosomes are inherited from different parents, while sister chromatids are identical copies formed by DNA replication.

Question 11

In a plant species, the sporophyte is diploid and produces spores by meiosis. What is the ploidy of the spores?

Accepted Answer

Haploid ($$n)$$

Question 12

Which mechanism does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during mitosis

Question 13

A couple is concerned about the risk of genetic disorders in their children. Which process is most likely to introduce new genetic variation into their offspring?

Accepted Answer

Mutation in the DNA of gametes

Question 14

If a sperm cell with $$n = 23$$ chromosomes fertilizes an egg cell with $$n = 23$$ chromosomes, what is the chromosome number of the resulting zygote?

Accepted Answer

$$2n = 46$$

Question 15

Which of the following scenarios best illustrates the concept of independent assortment?

Accepted Answer

A parent with genotype AaBb can produce gametes with AB, Ab, aB, or ab combinations.

Question 16

Which of the following equations correctly represents the number of possible chromosome combinations in human gametes due to independent assortment?

Accepted Answer

$$2^{23}$$

Question 17

Which of the following is a direct result of crossing over during meiosis?

Accepted Answer

Recombinant chromosomes with new combinations of alleles

Question 18

A scientist observes a cell with homologous chromosomes paired and exchanging genetic material. Which stage of meiosis is being observed?

Accepted Answer

Prophase I

Question 19

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

Accepted Answer

Separation of sister chromatids, resulting in four haploid cells

Question 20

Which of the following statements about the alternation of generations in plants is correct?

Accepted Answer

The diploid sporophyte produces haploid spores by meiosis, which grow into haploid gametophytes.

Meiosis and Sexual Life Cycles: Study Notes for General Biology

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