Test 4.5

A human cell containing 22 autosomes and a Y chromosome is A. a sperm. B. a zygote. C. a somatic cell of a male. D. a somatic cell of a female. E. an egg.

A

A pair of homologous chromosomes includes which of the following sets of DNA strands? A. four sister chromatids B. eight sister chromatids C. two single-stranded chromosomes that have synapsed D. two sister chromatids that have synapsed E. four unique chromosomes

A

For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? A. about 8 million B. 23 C. 46 D. 460 E. 920

A

Genetic variation occurs when chromosomes are shuffled in fertilization and what other process?. A. meiosis B. mitosis C. mutation D. genetic drift E. natural selection

A

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A. They have half the number of chromosomes and one-fourth the amount of DNA. B. They have twice the amount of cytoplasm and half the amount of DNA. C. They have half the number of chromosomes and half the amount of DNA. D. They have the same number of chromosomes and half the amount of DNA. E. They have half the amount of cytoplasm and twice the amount of DNA.

A

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? A. Length, centromere position, staining pattern, and traits coded for by their genes. B. Length and position of the centromere only. C. Length, centromere position, staining pattern, and DNA sequences. D. Length, centromere position, and staining pattern only. E. They have nothing in common except they are X-shaped.

A

Independent assortment of chromosomes is a result of A. the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. B. the random nature of the fertilization of ova by sperm. C. the relatively small degree of homology shared by the X and Y chromosomes. D. the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I, the random nature of the fertilization of ova by sperm, the random distribution of the sister chromatids to the two daughter cells during anaphase II, and the relatively small degree of homology shared by the X and Y chromosomes. E. the random distribution of the sister chromatids to the two daughter cells during anaphase II.

A

Refer to the following information and the figure to answer the following question. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure. A certain female's number 12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene. As cells in her ovaries undergo meiosis, her resulting eggs (ova) may have which of the following? A. one chromosome 12 with one blue gene and one chromosome 19 with one long gene B. either two number 12 chromosomes with blue genes or two with orange genes C. either one blue or one orange gene in addition to either one long or one short gene D. either two number 19 chromosomes with long genes or two with short genes

A

Refer to the life cycles illustrated in the figure to answer the following question. Which of the life cycles is typical for animals? A. I only B. II only C. III only D. I and II E. I and III

A

When we see chiasmata under a microscope, that lets us know which of the following has occurred? A. prophase I B. asexual reproduction C. meiosis II D. anaphase II E. separation of homologs

A

Which of the following best describes a karyotype? A. a display of each of the chromosomes of a single cell B. a photograph of all the cells with missing or extra chromosomes C. a pictorial representation of all the genes for a species D. the combination of all the maternal and paternal chromosomes of a species E. the collection of all the chromosomes in an individual organism

A

Which of the following defines a genome? A. the complete set of an organism's genes B. a karyotype C. the complete set of an organism's polypeptides D. representation of a complete set of a cell's polypeptides E. the complete set of a species' polypeptides

A

Which of the following occurs in meiosis but not in mitosis? A. synapsis of chromosomes B. production of daughter cells C. chromosome replication D. condensation of chromatin E. alignment of chromosomes at the equator

A

Which of these statements is false? A. At sexual maturity, ovaries and testes produce diploid gametes by meiosis. B. Sexual life cycles differ with respect to the relative timing of meiosis and fertilization. C. In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. D. Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote. E. In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY).

A

You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in the figure. Refer to the graph to answer the following question. Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle? A. I B. II C. III D. either I or II E. either I or III

A

Select all that apply. A. Spores B. Gametes (sperm and eggs) C. Multicellular adult organisms

AB

A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following? A. 63 chromosomes, each with three chromatids B. 63 chromosomes in 21 sets of 3 C. 21 chromosome pairs and 21 unique chromosomes D. 63 chromosomes in 31 1/2 pairs

B

After telophase I of meiosis, the chromosomal makeup of each daughter cell is A. diploid, and the chromosomes are each composed of two chromatids. B. haploid, and the chromosomes are each composed of two chromatids. C. tetraploid, and the chromosomes are each composed of two chromatids. D. diploid, and the chromosomes are each composed of a single chromatid. E. haploid, and the chromosomes are each composed of a single chromatid.

B

At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype? A. telophase B. metaphase C. anaphase D. interphase E. prophase

B

Experiments with cohesins have found that A. cohesins are protected from destruction throughout meiosis I and II. B. cohesins are protected from cleavage at the centromere during meiosis I. C. cohesins are cleaved from chromosomes at the centromere before anaphase I. D. a protein cleaves cohesins before metaphase I. E. a protein that cleaves cohesins would cause cellular death.

B

How are sister chromatids and homologous chromosomes different from each other? A. They are not different. Homologous chromosomes and sister chromatids are both identical copies of each other. B. Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication. C. Homologous chromosomes are identical copies of each other. One sister chromatid comes from the father, and one comes from the mother. D. Homologous chromosomes are closely associated with each other in both mitosis and meiosis. Sister chromatids are only associated with each other during mitosis. E. Sister chromatids are only formed during mitosis. Homologous chromosomes are formed during meiosis.

B

How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n = 8)? A. 8 B. 16 C. 2 D. 4 E. 32

B

In alternation of generations, what is the diploid stage of a plant that follows fertilization called? A. spore B. sporophyte C. gametophyte D. karyotype E. chiasmata

B

Refer to the life cycles illustrated in the figure to answer the following question. Which of the life cycles is typical for most fungi and some protists? A. I only B. II only C. III only D. I and II E. I and III

B

Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes? A. sporophyte meiosis B. gametophyte mitosis C. sporophyte mitosis D. gametophyte meiosis E. alternation of generations

B

The following question refers to the essential steps in meiosis described below. 1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus 2. Alignment of tetrads at the metaphase plate 3. Separation of sister chromatids 4. Separation of the homologs; no uncoupling of the centromere 5. Synapsis; chromosomes moving to the middle of the cell in pairs Which of the steps takes place in both mitosis and meiosis? A. 2 B. 3 C. 5 D. 2 and 3 only E. 2, 3, and 5

B

WHAT IS CROSSING OVER? A.the movement of genetic material from one chromosome to a nonhomologous chromosome B. the exchange of homologous portions of nonsister chromatids C. making an RNA copy of a DNA strand D. a direct consequence of the separation of sister chromatids E. also referred to as the "independent assortment of chromosomes"

B

Which is the smallest unit containing the entire human genome? A. all of the DNA of one human B. one human somatic cell C. one human chromosome D. the entire human population E. one human gene

B

Which life cycle stage is found in plants but not animals? A. zygote B. multicellular haploid C. unicellular diploid D. gamete E. multicellular diploid

B

Which of the following best describes the frequency of crossing over in mammals? A. ~50 per chromosome pair B. at least 1-2 per chromosome pair C. ~2 per meiotic cell D. a very rare event among hundreds of cells E. ~1 per pair of sister chromatids

B

You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in the figure. Refer to the graph to answer the following question. Which sample might represent an animal cell in the G2 phase of the cell cycle? A. I B. II C. III D. both I and II E. either II or III

B

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A. It must be sexually reproducing. B. It must be an animal. C. Its gametes must have 23 chromosomes. D. It must be a primate. E. It must be human.

C

Heritable variation is required for which of the following? A. meiosis B. mitosis C. evolution D. the production of a clone E. asexual reproduction

C

Homologous chromosomes move toward opposite poles of a dividing cell during A. binary fission. B. fertilization. C. meiosis I. D. meiosis II. E. mitosis.

C

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents? A. It has one-fourth the DNA and one-half the chromosomes as the originating cell. B. It has the same number of chromosomes but each of them has different alleles than another cell from the same meiosis. C. It has half the amount of DNA as the cell that began meiosis. D. It has half the chromosomes but twice the DNA of the originating cell. E. It is identical in content to another cell from the same meiosis.

C

If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following? A. up to, but not more than, 18 different traits B. up to 18 genes for that trait C. at most, 2 alleles for that gene D. a haploid number of 9 chromosomes E. up to 18 chromosomes with that gene

C

If we continued to follow the cell lineage from question 5, then the DNA content of a single cell at metaphase of meiosis II would be A. 0.5x. B. 4x. C. x. D. 0.25x. E. 2x.

C

Independent assortment of chromosomes occurs. A. The statement is true for meiosis II only. B. The statement is true for mitosis and meiosis II. C. The statement is true for meiosis I only. D. The statement is true for mitosis and meiosis I. E. The statement is true for mitosis only.

C

Look at the cell in the figure. Based on this figure, which of the following statements is true? A. It is impossible to tell whether the cell is haploid or diploid. B. This cell is haploid. C. This cell is diploid.

C

Mitosis is commonly found in all but one of the following. Select the exception: A. a diploid animal cell B. a haploid plant cell C. a haploid animal cell D. a diploid plant cell

C

The somatic cells of a privet shrub each contain 46 chromosomes. To be as different as they are from human cells, which have the same number of chromosomes, which of the following must be true? A. Genes on a particular privet chromosome, such as the X, must be on a different human chromosome, such as number 18. B. Privet sex cells have chromosomes that can synapse with human chromosomes in the laboratory. C. Genes of privet chromosomes are significantly different than those in humans. D. Privet shrubs must be metabolically more like animals than like other shrubs. E. Privet cells cannot reproduce sexually.

C

This chromosome has two chromatids, joined at the centromere. What process led to the formation of the two chromatids? A. The two chromatids were formed by synapsis and the formation of a synaptonemal complex. B. The two chromatids were formed by fertilization, bringing together maternal and paternal chromatids. C. The two chromatids were formed by replication of the DNA within a single chromatid.

C

To visualize and identify meiotic cells at metaphase with a microscope, what would you look for? A. individual chromosomes all at the cell's center B. the synaptonemal complex C. pairs of homologous chromosomes all aligned at the cell's center D. an uninterrupted spindle array E. sister chromatids of a replicated chromosome grouped at the poles

C

Two sister chromatids are joined at the centromere prior to meiosis. Which statement is correct? A. The cell that contains these sister chromatids must be diploid. B. These chromatids make up a diploid chromosome. C. Barring mutation, the two sister chromatids must be identical.

C

What is the best evidence telling you whether this cell is diploid or haploid? A. The cell is haploid because the chromosomes are not found in pairs. B. The cell is diploid because each chromosome consists of two chromatids. C. The cell is diploid because it contains two sets of chromosomes.

C

When does the synaptonemal complex disappear? A.mid-prophase of meiosis I B. during fertilization or fusion of gametes C. late prophase of meiosis I D. early anaphase of meiosis I E. late metaphase of meiosis II

C

When homologous chromosomes cross over, what occurs? A. Two chromatids get tangled, resulting in one re-sequencing its DNA. B. Each of the four DNA strands of a homologous pair is broken, and the pieces are mixed. C. Specific proteins break the two strands of nonsister chromatids and re-join them. D. Two sister chromatids exchange identical pieces of DNA. E. Maternal alleles are "corrected" to be like paternal alleles and vice versa.

C

Which of the following is an example of alternation of generations? A. A grandparent and grandchild each have dark hair, but the parent has blond hair. B. A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote. C. A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte). D. A diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to produce a tetraploid cell. E. A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization, which is immediately followed by meiosis.

C

Which of the following might result in a human zygote with 45 chromosomes? A. lack of chiasmata in prophase I B. failure of the egg nucleus to be fertilized by the sperm C. an error in either egg or sperm meiotic anaphase D. an error in the alignment of chromosomes on the metaphase plate E. fertilization of a 23 chromosome human egg by a 22 chromosome sperm of a closely related species

C

Which of these is a way that the sexual life cycle increases genetic variation in a species? A. by allowing an increase in cell number B. by decreasing mutation frequency C. by allowing crossing over D. by increasing gene stability E. by conserving chromosomal gene order

C

If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A. Force the plant to self-pollinate to obtain an identical one. B. Breed this plant with another plant with much weaker traits. C. Add nitrogen to the soil of the offspring of this plant so the desired traits continue. D. Clone the plant asexually to produce an identical one. E. Backtrack through her previous experiments to obtain another plant with the same traits.

D

Meiosis II is similar to mitosis in that A.the chromosome number is reduced. B. homologous chromosomes synapse. C. DNA replicates before the division. D. sister chromatids separate during anaphase. E. the daughter cells are diploid.

D

Mitosis results in the formation of how many cells; meiosis results in the formation of how many cells? A. two diploid cells ... two haploid cells B. two diploid cells ... two diploid cells C. four haploid cells ... two diploid cells D. two diploid cells ... four haploid cells E. four diploid cells ... four haploid cells

D

Refer to the drawings in the figure of a single pair of homologous chromosomes as they might appear during various stages of either mitosis or meiosis, and answer the following question. Which diagram(s) represent anaphase II of meiosis? A. II only B. III only C. IV only D. V only E. either II or V

D

Refer to the following information and the figure to answer the following question. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure. If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types? A. only blue short gene eggs B. three-fourths blue short and one-fourth orange short gene eggs C. three-fourths blue long and one-fourth orange short gene eggs D. one-half blue short and one-half orange short gene eggs E. only orange short gene eggs

D

Refer to the life cycles illustrated in the figure to answer the following question. In a life cycle such as that shown in part III of the figure, if the zygote's chromosome number is 10, which of the following will be true? A. The sporophyte and gametophyte each have 20 chromosomes per cell. B. The sporophyte and gametophyte each have 10 chromosomes per cell. C. The sporophyte and gametophyte each have 5 chromosomes per cell. D. The sporophyte's chromosome number per cell is 10 and the gametophyte's is 5. E. The sporophyte's chromosome number per cell is 5 and the gametophyte's is 10.

D

Refer to the life cycles illustrated in the figure to answer the following question. In part III of the figure, the progression of events corresponds to which of the following series? A. zygote, mitosis, gametophyte, mitosis, fertilization, zygote, mitosis B. gametophyte, meiosis, zygote, spores, sporophyte, zygote C. fertilization, mitosis, multicellular haploid, mitosis, spores, sporophyte D. sporophyte, meiosis, spore, mitosis, gametophyte, mitosis, gametes, fertilization E. meiosis, fertilization, zygote, mitosis, adult, meiosis

D

To view and analyze human chromosomes in a dividing cell, which of the following is/are required? A. a stain particular to human cells B. a scanning electron microscope C. radioactive staining D. DNA staining and a light microscope E. fluorescent staining and a transmission electron microscope

D

What number and types of chromosomes are found in a human somatic cell? A. 22 autosomes and 1 sex chromosome B. 21 autosomes and 2 sex chromosomes C. n chromosomes D. 44 autosomes and 2 sex chromosomes E. 45 autosomes and 1 sex chromosome

D

Which of these is a karyotype? A. a display of all the cell types in an organism. B. the appearance of an organism. C. a display of a cell's mitotic stages. D. organized images of a cell's chromosomes. E. a natural cellular arrangement of chromosomes in the nucleus.

D

Which of the following is a true statement about sexual vs. asexual reproduction? A. In asexual reproduction, offspring are produced by fertilization without meiosis. B. Sexual reproduction requires that parents be diploid. C. Asexual reproduction produces only haploid offspring. D. In sexual reproduction, individuals transmit 50% of their genes to each of their offspring. E. Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi.

D

Which of the following occurs during meiosis but not during mitosis? A.Chromosomes condense. B. Chromosomes align at the metaphase plate. C. A spindle apparatus forms. D. Synapsis occurs. E. Chromosomes migrate to opposite poles.

D

Asexual reproduction _____. A; requires both meiosis and mitosis B. is limited to plants C. is limited to single-cell organisms D. leads to a loss of genetic material E. produces offspring genetically identical to the parent

E

Chromatids are separated from each other. A. The statement is true for meiosis II only. B. The statement is true for meiosis I only. C. The statement is true for mitosis and meiosis I. D. The statement is true for mitosis only. E. The statement is true for mitosis and meiosis II.

E

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores A. II, IV, and V B. I, II, and IV C. I, IV, and V D. I, II, III, IV, and V E. II, III, and IV

E

For the following question, match the key event of meiosis with the stages listed below. I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II Centromeres of sister chromatids disjoin and chromatids separate. A. II B. III C. IV D. V E. VII

E

For the following question, match the key event of meiosis with the stages listed below. I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II Synaptonemal complexes form or are still present. A. II and VI only B. I and IV only C. I, II, III, and IV only D. I and VIII only E. I only

E

For what purpose(s) might a karyotype be prepared? A. for prenatal screening, to determine if a fetus has the correct number of chromosomes B. to determine whether a fetus is male or female C. to detect the possible presence of chromosomal abnormalities such as deletions, inversions, or translocations D. The first and second answers are correct. E. The first three answers are correct.

E

If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be A. 4x. B. 0.5x. C. x. D. 0.25x. E. 2x.

E

Refer to the following information and the figure to answer the following question. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure. A female with a paternal set of one orange and one long gene chromosome and a maternal set comprised of one blue and one short gene chromosome is expected to produce which of the following types of eggs after meiosis? A. All eggs will have maternal types of gene combinations. B. All eggs will have paternal types of gene combinations. C. Half the eggs will have maternal and half will have paternal combinations. D. Each egg has a three-fourths chance of having blue long, one-fourth blue short, three-fourths orange long, or one-fourth orange short combinations. E. Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short combinations.

E

The human X and Y chromosomes A. are called autosomes. B. are almost entirely homologous, despite their different names. C. are about the same size and have approximately the same number of genes. D. are both present in every somatic cell of males and females alike. E. include genes that determine an individual's sex.

E

The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following? A. mitosis in her ovary B. telophase II of one meiotic event C. metaphase I of one meiotic event D. telophase I of one meiotic event E. either anaphase I or II

E

There is a group of invertebrate animals called rotifers, among which a particular group of species reproduces, as far as is known, only asexually. These rotifers, however, have survived a long evolutionary history without evidence of having been overcome by excessive mutations.How is natural selection related to sexual reproduction as opposed to asexual reproduction? A. Sexual reproduction results in the most appropriate and healthiest balance of two sexes in the population. B. Sexual reproduction allows the greatest number of offspring to be produced. C. Sexual reproduction results in the greatest number of new mutations. D. Sexual reproduction utilizes far less energy than asexual reproduction. E. Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.

E

Use the following information to answer the next question. There is a group of invertebrate animals called rotifers, among which a particular group of species reproduces, as far as is known, only asexually. These rotifers, however, have survived a long evolutionary history without evidence of having been overcome by excessive mutations. Since the rotifers develop from eggs, but asexually, what can you predict? A. All males can produce eggs. B. The eggs and the zygotes are all haploid. C. While asexual, both males and females are found in nature. D. The animals are all hermaphrodites. E. No males can be found.

E

Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must have which of the following properties? A.They must be removed before meiosis can begin. B. They must reattach to chromosomes during G1. C. They must persist throughout the cell cycle. D. They must be intact for nuclear envelope re-formation. E. They must be removed before sister chromatids or homologous chromosomes can separate.

E

Which of the following can utilize both mitosis and meiosis in the correct circumstances? A. any diploid animal cell B. a haploid animal cell C. a diploid cell from a plant stem D. an archaebacterium E. a plantlike protist

E

Which of the following is true of a species that has a chromosome number of 2n = 16? A. During the S phase of the cell cycle there will be 32 separate chromosomes. B. The species is diploid with 32 chromosomes per cell. C. A gamete from this species has four chromosomes. D. The species has 16 sets of chromosomes per cell. E. Each cell has eight homologous pairs.

E

Which of the following happens at the conclusion of meiosis I? A. Cohesins are cleaved at the centromeres. B. Sister chromatids are separated. C. Homologous chromosomes of a pair are separated from each other. D. The chromosome number per cell is conserved. E. Four daughter cells are formed.

c