Question 1

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

Accepted Answer

Because sexual reproduction involves the combination of genes from two parents, independent assortment, crossing over, and random fertilization.

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 combinations of chromosomes can be produced in its gametes by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 6

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry genes controlling the same inherited characters, but may have different alleles.

Question 7

In the life cycle of most fungi and some protists, which of the following is true?

Accepted Answer

The only diploid stage is the single-celled zygote.

Question 8

A plant species has a life cycle that includes both a multicellular diploid stage and a multicellular haploid stage. What is this type of life cycle called?

Accepted Answer

Alternation of generations

Question 9

Which of the following events occurs in meiosis but not in mitosis?

Accepted Answer

Pairing of homologous chromosomes and crossing over

Question 10

A geneticist observes that a child has a combination of traits not found in either parent. Which process most likely contributed to this genetic variation?

Accepted Answer

Crossing over during prophase I of meiosis

Question 11

Which of the following best describes the difference between asexual and sexual reproduction?

Accepted Answer

Asexual reproduction produces genetically identical offspring, while sexual reproduction produces genetically unique offspring.

Question 12

During which stage of meiosis do homologous chromosomes separate and move toward opposite poles?

Accepted Answer

Anaphase I

Question 13

Which mechanism is primarily responsible for the maintenance of a constant chromosome number across generations in sexually reproducing species?

Accepted Answer

Meiosis followed by fertilization

Question 14

If a sperm cell contains $$n = 23$$ chromosomes, how many chromosomes will be present in the zygote after fertilization with an egg?

Accepted Answer

$$46$$

Question 15

Which of the following contributes most directly to the genetic uniqueness of siblings (except identical twins)?

Accepted Answer

All of the above

Question 16

A mutation occurs in a gene located on a chromosome. What is the most likely long-term evolutionary consequence if this mutation is beneficial?

Accepted Answer

It will increase in frequency in the population due to natural selection.

Question 17

Which of the following equations correctly represents the number of possible chromosome combinations due to independent assortment in gametes, where $$n is $$the haploid number?

Accepted Answer

$$2^n$$

Question 18

In a medical case, a patient is found to have an abnormal number of chromosomes in their somatic cells. Which process most likely failed during gamete formation?

Accepted Answer

Proper segregation of chromosomes during meiosis

Question 19

Which of the following statements about the products of meiosis is correct?

Accepted Answer

Each daughter cell is haploid and genetically distinct from the parent cell and each other.

Question 20

A botanist discovers a new plant species in which the sporophyte is diploid and the gametophyte is haploid. Which process produces gametes in this species?

Accepted Answer

Mitosis

Meiosis and Sexual Life Cycles: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard