Question 1

Quaking aspen can send out underground stems. New trees can sprout from these stems. This is an example of what type of reproduction?

Accepted Answer

Quaking aspen reproduces asexually through underground stems called rhizomes, which can give rise to new trees. This type of reproduction does not involve the fusion of gametes and is therefore considered asexual.

Question 2

The diploid number of a roundworm species is 4. You have a male and a female roundworm that are planning a family. Assuming random segregation of homologues during meiosis and no crossover, how many different possible combinations of chromosomes might there be in the offspring?

Accepted Answer

Each parent contributes 2 unique homologous chromosomes to their offspring. Thus, there are 2^2 possible combinations from each parent. With two parents, there would be 2^2 x 2^2 = 16 possible combinations of chromosomes in the offspring.

Question 3

Figure 13.6
-In the diploid cell above there are chromosomes and chromatids.

Accepted Answer

In a diploid cell, the number of chromosomes is typically constant for a given species, and each chromosome consists of two chromatids before cell division. Therefore, if there are 4 chromosomes, there would be 8 chromatids, as each chromosome would consist of 2 chromatids.

Question 4

Figure 13.6
-Just prior to meiosis, DNA is replicated. Each resulting piece of replicated DNA is considered to be chromosomes) and is made up of chromatics).

Accepted Answer

Just prior to meiosis, DNA replication results in each chromosome being composed of two sister chromatids, hence the correct answer is 1 chromosome made up of 2 chromatids.

Question 5

Which of the following would enable you to detect aneuploidy?

Accepted Answer

Aneuploidy refers to an abnormal number of chromosomes, which can be detected by karyotyping. Karyotyping is the process of analyzing chromosomes in a sample of cells to look for abnormalities in their number, size, and shape. This is commonly done by staining the chromosomes and visualizing them under a microscope. Synapsis refers to the pairing of homologous chromosomes during meiosis, autosomy refers to the inheritance of genetic material from chromosomes that are not sex chromosomes, and syngamy refers to the fusion of gametes during fertilization. None of these processes specifically enable the detection of aneuploidy.

Question 6

If meiosis produces haploid cells, how is the diploid number restored for those organisms that spend most of their life cycle in the diploid state?

Accepted Answer

The diploid number is restored through fertilization, where two haploid gametes fuse to form a diploid zygote. This is a crucial step in sexual reproduction, as it allows for genetic diversity and the shuffling of alleles between individuals.

Question 7

An advantage of asexual reproduction is that it

Accepted Answer

Asexual reproduction allows for rapid and efficient colonization of new habitats because only one individual is needed to reproduce and colonize. This can give the species an advantage over sexual reproduction in environments where being the first to colonize is crucial to survival.

Question 8

When we first see chiasmata under a microscope, we know that

Accepted Answer

Chiasmata are formed during prophase I of meiosis, when homologous chromosomes exchange genetic material through crossing over. Therefore, the presence of chiasmata indicates that prophase I is occurring.

Question 9

Sexual reproduction

Accepted Answer

Sexual reproduction introduces genetic variation through recombination, allowing for the production of diverse phenotypes that may enhance survival of a population in a changing environment. This can help a population better adapt to new challenges, such as the emergence of new pathogens or changing environmental conditions.

Question 10

Which of the following is the difference between trisomy and triploidy?

Accepted Answer

Trisomy refers to a condition in which there are three copies of a specific chromosome, while triploidy refers to a condition in which there are three copies of every chromosome. So, option B is the correct answer. Options A and C are incorrect because they mix up the definitions of trisomy and triploidy. Option D is incorrect because, as explained, trisomy and triploidy are two different conditions.

Question 11

Plants produce more seeds when they reproduce asexually than sexually. Yet most plants reproduce sexually in nature. What is the probable explanation for the prevalence of sexual reproduction? Sexual reproduction

Accepted Answer

Sexual reproduction mixes up alleles, contributing to variation in a species. This variation increases the likelihood that some members of the species will survive in changing environments or in the face of new diseases or predators. This is especially important for long-term survival in evolving ecosystems, which is why sexual reproduction is prevalent in nature despite the greater number of seeds produced through asexual reproduction.

Question 12

Which of the following is an example of monosomy?

Accepted Answer

Turner's sydrome is caused by the presence of only one copy of the X chromosome (XO), leading to monosomy of that chromosome. Down's syndrome is caused by trisomy of chromosome 21, and Klinefelter's syndrome is caused by an extra X chromosome (XXY).

Question 13

The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. There is/are different possible combinations) of genes in the daughter cells of meiosis because .

Accepted Answer

During meiosis, the two homologous chromosomes can cross over, swapping alleles between them. This leads to different combinations of genes in the daughter cells, resulting in more than two possible combinations. Therefore, the best choice is C.

Question 14

Genetic recombination takes place in which of the following processes?

Accepted Answer

Genetic recombination occurs during crossing over in prophase I of meiosis, where homologous chromosomes exchange genetic material.

Question 15

Which of the following types of reproduction is associated with the most genetic variation among offspring?

Accepted Answer

Sexual reproduction involves the exchange and recombination of genetic material between two parents, which leads to the production of genetically diverse offspring. In asexual reproduction, offspring are produced through mitosis without the exchange of genetic material, resulting in genetically identical offspring. Budding and binary fission are both types of asexual reproduction. Therefore, sexual reproduction is the type of reproduction associated with the most genetic variation among offspring.

Question 16

In sexual reproduction, the variation among offspring, and the fact that they are genetically different from their parents, is due to which of the following?

Accepted Answer

All of the above contribute to genetic variability in sexual reproduction. The random process of fertilization leads to different combinations of the genetic material from each parent. The random alignment of homologues during meiosis I and the resulting crossing over during meiosis I also shuffle the genetic material, leading to further variation among offspring.

Question 17

In 1985, Hassold and Chiu found that the likelihood of miscarriage increased with maternal age. What is the most likely explanation for the relationship between age and miscarriage?

Accepted Answer

The likelihood of miscarriage increases with maternal age because ova are arrested in meiosis until ovulation, and completion of meiosis in the older woman is more likely to result in aneuploidy or other chromosomal abnormalities.

Question 18

Adaptation to a changing environment is likely to occurs most quickly through which of the following processes?

Accepted Answer

Sexual reproduction increases genetic variation within a population, which enhances the potential for adaptation to changing environments by combining genes from two parents.

Question 19

Figure 13.6
-In which phase of meiosis do sister chromatids separate?

Accepted Answer

Sister chromatids separate during anaphase II of meiosis.

Question 20

Asexual reproduction takes place by which of the following processes?

Accepted Answer

Asexual reproduction takes place through the process of mitosis, where the parent cell divides into two genetically identical daughter cells. Fertilization involves the fusion of gametes (reproductive cells) from two different individuals, while meiosis involves the formation of haploid cells with half the number of chromosomes as the parent cell. Chromosome exchange between organisms of the same species is a form of sexual reproduction.

Quiz 13: Meiosis