Question 1

During which of the following phases of meiosis do homologous chromosomes separate?

Accepted Answer

Homologous chromosomes separate during anaphase I of meiosis. During this phase, the homologous chromosomes, which have paired up during prophase I, separate and move to opposite poles of the cell. In contrast, anaphase II of meiosis involves the separation of sister chromatids. Mitosis also involves the separation of sister chromatids, but not homologous chromosomes.

Question 2

During which of the following processes does independent assortment of chromosomes occur?

Accepted Answer

Independent assortment of chromosomes occurs during meiosis I when homologous chromosomes separate and move to different daughter cells independently of each other. In meiosis II, sister chromatids separate, but these chromatids are already genetically identical due to the earlier separation of homologous chromosomes in meiosis I. Mitosis does not involve the independent assortment of chromosomes, as it only results in the formation of daughter cells that are genetically identical to the parent cell.

Question 3

Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?

Accepted Answer

Ova (eggs) are haploid cells so they have half the number of chromosomes as somatic cells. Therefore, an ovum from a roundworm would have two chromosomes.

Question 4

During which of the following processes do homologous pairs of chromosomes align adjacent to one another at the metaphase plate of a cell?

Accepted Answer

Homologous pairs of chromosomes align adjacent to one another at the metaphase plate during metaphase I of meiosis. In metaphase of mitosis, individual chromosomes line up at the metaphase plate. Telophase II of meiosis and metaphase II of meiosis are both stages where individual chromosomes line up at the metaphase plate, not homologous pairs.

Question 5

During which of the following phases of meiosis do centromeres split and sister chromatids migrate to opposite poles of the cell?

Accepted Answer

During anaphase II of meiosis, the centromeres split and sister chromatids separate and migrate to opposite poles of the cell. This is the phase where the final separation of genetic material occurs before the formation of four new haploid cells. Anaphase I and telophase I involve the separation of homologous chromosomes, whereas telophase II involves the formation of new nuclei around the separated sister chromatids.

Question 6

How does natural selection apply to sexual reproduction as opposed to asexual reproduction?

Accepted Answer

Sexual reproduction allows for genetic recombination and the creation of new gene combinations, which can lead to variations in traits that may provide advantages in survival and reproduction. Asexual reproduction, on the other hand, produces genetically identical offspring, which may be less adaptable to changing environments and less likely to have advantageous traits. Therefore, natural selection is more effective in sexual reproduction.

Question 7

Crossing over of chromosomes normally takes place during which of the following processes?

Accepted Answer

Crossing over of chromosomes occurs during meiosis I, specifically during prophase I. It does not occur during mitosis or meiosis II.

Question 8

Which of the following statements describes one characteristic of each chromosome in a cell during the entire process of meiosis I?

Accepted Answer

The answer of Which of the following statements describes one...

Question 9

Independent assortment of chromosomes is a result of which of the following processes?

Accepted Answer

Independent assortment of chromosomes occurs during meiosis I, specifically during metaphase I when homologous pairs of chromosomes line up at the metaphase plate. The different ways these pairs can line up result in different combinations of maternal and paternal chromosomes in the resulting gametes.

Question 10

Which of the following processes occur during meiosis but not mitosis?

Accepted Answer

Meiosis is the process of cell division that produces haploid cells from diploid cells. This process occurs only in the reproductive organs of sexually reproducing organisms. During meiosis, diploid cells undergo two rounds of cell division, resulting in four haploid cells. This process allows for genetic diversity in sexual reproduction. In mitosis, a single cell divides into two identical daughter cells.

Question 11

For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes based on the independent assortment of chromosomes during meiosis?

Accepted Answer

The number of possible combinations of maternal and paternal chromosomes in the gametes is 2^n, where n is the haploid number of chromosomes. Therefore, for a species with a haploid number of 23 chromosomes, there are 2^23, or about 8 million, different combinations of maternal and paternal chromosomes possible for the gametes based on the independent assortment of chromosomes during meiosis.

Question 12

Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Biological systems have multiple processes, such as reproduction, that affect genetic variation. They are evolutionarily conserved and shared by various organisms. Which of the following statements best represents the connection between reproduction and evolution?

Accepted Answer

Sexual reproduction involves the shuffling of genetic material between individuals through processes such as crossing over and independent assortment, which can lead to the generation of new combinations of alleles and hence genetic diversity. Mutations can occur both before and after fertilization, but it is not solely dependent on mutations occurring after fertilization. Asexually reproducing organisms can also introduce genetic diversity through mechanisms such as horizontal gene transfer.

Question 13

Which of the following statements describes a major difference between meiosis II and mitosis in a diploid animal?

Accepted Answer

Meiosis II occurs in haploid cells because it follows meiosis I, which reduces the chromosome number by half. Mitosis, on the other hand, typically occurs in diploid cells.

Question 14

Imagine that there are 25 different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment?

Accepted Answer

Sexual reproduction increases genetic diversity, which can enhance the ability of species to adapt to changing environments and resist diseases.

Question 15

The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species?

Accepted Answer

Since there is only one chromosome in each daughter cell following meiosis, independent assortment alone would not result in significant genetic diversity. Crossing over is also unlikely to contribute since there are no homologous chromosomes to exchange genetic material. However, random fertilization can introduce diversity through the joining of gametes from different individuals with different genetic variations.

Question 16

A human cell containing 22 autosomes and a Y chromosome is

Accepted Answer

The answer of A human cell containing 22 autosomes and...

Question 17

Which of the following processes facilitates the fastest way for organisms to adapt to a changing environment?

Accepted Answer

Sexual reproduction allows for the mixing of genetic information between two individuals, creating offspring with unique combinations of alleles. This increases genetic diversity within a population, which can facilitate adaptations to changing environments more quickly than asexual reproduction or mitosis. While mutations can introduce new alleles into a population, they occur at a relatively slow rate compared to sexual reproduction.

Question 18

Which of the following statements describes a major difference between mitosis and meiosis I in a diploid organism?

Accepted Answer

Sister chromatids separate during mitosis, ensuring each daughter cell receives an identical set of chromosomes. In contrast, meiosis I is characterized by the separation of homologous chromosomes, leading to daughter cells with a haploid set of chromosomes, each consisting of one chromosome from each homologous pair.

Question 19

In eukaryotes, genetic information is passed to the next generation by processes that include mitosis or meiosis. Which of the following explanations correctly identifies the process and supports the claim that heritable information is passed from one generation to another?

Accepted Answer

Asexual reproduction involves a single individual passing copies of its genes to its offspring without the fusion of gametes, thereby passing on heritable genetic information to the next generation.

Question 20

Which of the following processes occurs when homologous chromosomes cross over in meiosis I?

Accepted Answer

Crossing over during meiosis I involves the exchange of corresponding segments of non-sister chromatids. This contributes to genetic variation as the exchange can result in the exchange of different alleles or combinations of alleles on the chromosomes. The other choices are incorrect as they do not accurately describe the process of crossing over.

Quiz 13: Meiosis and Sexual Life Cycles