Exam 4: Biosciences 1
3) In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true?
A) A plant species (privet shrubs) has 46 chromosomes per cell.
26) Which of the following happens at the conclusion of meiosis I?
A) Homologous chromosomes are separated.
52) Which diagram represents anaphase I of meiosis? (Look at picture 13.2)
A) I
54) Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle? (Look at picture 13.3)
A) I
56) Which sample might represent a zygote? (Look at picture 13.3)
A) I
47) Which of the life cycles is typical for animals? (Look at picture 13.1)
A) I only
For the following questions, match the key event of meiosis with the stages listed below. I. Prophase I V. Prophase I II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 39) Synaptonemal complexes form or are still present.
A) I only
18) 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 half the amount of DNA as the cell that began meiosis.
63) How is natural selection related to sexual reproduction as opposed to asexual reproduction?
A) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.
51) In a life cycle such as that shown in part III of Figure 13.1, if the zygote's chromosome number is 10, which of the following will be true?
A) The sporophyte's chromosome number per cell is 10 and the gametophyte's is 5.
64) A human cell containing 22 autosomes and a Y chromosome is
A) a sperm.
20) Which of the following might result in a human zygote with 45 chromosomes?
A) an error in either egg or sperm meiotic anaphase
31) 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) at most, 2 alleles for that gene
42) How does the sexual life cycle increase the genetic variation in a species?
A) by allowing crossing over
2) The human genome is minimally contained in which of the following?
A) every human cell
25) When does the synaptonemal complex disappear?
A) late prophase of meiosis I
67) Meiosis II is similar to mitosis in that
A) sister chromatids separate during anaphase.
44) 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.
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 41) Which of the steps takes place in both mitosis and meiosis?
B) 3
15) 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?
B) 63 chromosomes in 21 sets of 3
12) Which of the following is an example of alternation of generations?
B) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).
55) Which sample might represent an animal cell in the G2 phase of the cell cycle? (Look at picture 13.3)
B) II
For the following questions, match the key event of meiosis with the stages listed below. I. Prophase I V. Prophase I II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 38) Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment.
B) II
49) Which of the life cycles is typical for most fungi and some protists? (Look at picture 13.1)
B) II only
4) Which of the following is a true statement about sexual vs. asexual reproduction?
B) In sexual reproduction, individuals transmit 50% of their genes to each of their offspring.
27) A cell divides to produce two daughter cells that are genetically different.
B) The statement is true for meiosis I only.
29) Independent assortment of chromosomes occurs.
B) The statement is true for meiosis I only.
17) Which of the following best describes a karyotype?
B) a display of each of the chromosomes of a single cell
11) Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes?
B) gametophyte mitosis
66) Homologous chromosomes move toward opposite poles of a dividing cell during
B) meiosis I.
6) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
B) metaphase
50) In part III of Figure 13.1, the progression of events corresponds to which of the following series?
B) sporophyte, meiosis, spore, mitosis, gametophyte, mitosis, gametes, fertilization
30) Which of the following occurs in meiosis but not in mitosis?
B) synapsis of chromosomes
34) A tetrad includes which of the following sets of DNA strands?
B) two sets of sister chromatids that have synapsed
1) 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?
C) Clone the plant asexually to produce an identical one.
8) Which of the following is true of a species that has a chromosome number of 2n = 16?
C) Each cell has eight homologous pairs.
21) 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?
C) Genes of privet chromosomes are significantly different than those in humans.
9) 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
C) II, III, and IV
48) Which of the life cycles is typical for plants and some algae? (Look at picture 13.1)
C) III only
22) 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?
C) Length, centromere position, staining pattern, and traits coded for by their genes.
46) When homologous chromosomes crossover, what occurs?
C) Specific proteins break the two strands and re-join them with their homologs.
32) 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?
C) They must be removed before anaphase can occur.
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. 62) In these asexual rotifers, how does variation occur without meiosis and fertilization?
C) Variation is caused by mutation and maintained by selection.
45) Which of the following best describes the frequency of crossing over in mammals?
C) at least 1-2 per chromosome pair
33) Experiments with cohesins have found that
C) cohesins are protected from cleavage at the centromere during meiosis I.
58) 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? (Look at picture 13.4)
C) one-half blue short and one-half orange short gene eggs
16) A karyotype results from which of the following?
C) the ordering of human chromosome images
69) If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of a single cell at metaphase of meiosis II would be
C) x.
70) 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)?
D) 16
68) 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
D) 2x.
10) Which of these statements is false?
D) At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
36) To view and analyze human chromosomes in a dividing cell, which of the following is/are required?
D) DNA stain and a light microscope
59) 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? (Look at picture 13.4)
D) Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short combinations.
24) How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?
D) They have half the number of chromosomes and one-fourth the amount of DNA.
53) Which diagram(s) represent anaphase II of meiosis? (Look at picture 13.2)
D) V only
19) Which of the following can utilize both mitosis and meiosis in the correct circumstances?
D) a plantlike protist
23) After telophase I of meiosis, the chromosomal makeup of each daughter cell is
D) haploid, and the chromosomes are each composed of two chromatids.
7) The human X and Y chromosomes
D) include genes that determine an individual's sex.
65) Which life cycle stage is found in plants but not animals?
D) multicellular haploid
57) 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? (Look at picture 13.4)
D) one chromosome 12 with one blue gene and one chromosome 19 with one long gene
35) When we see chiasmata under a microscope, that lets us know which of the following has occurred?
D) prophase I
14) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
E) Its gametes must have 23 chromosomes.
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. 60) Since the rotifers develop from eggs, but asexually, what can you predict?
E) No males can be found.
28) Chromatids are separated from each other.
E) The statement is true for mitosis and meiosis II.
For the following questions, match the key event of meiosis with the stages listed below. I. Prophase I V. Prophase I II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 40) Centromeres of sister chromatids disjoin and chromatids separate.
E) VII
43) For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
E) about 8 million
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. 61) Assuming that the eggs are diploid, tetraploid, or partially tetraploid, what mechanism may still occur without fertilization?
E) crossing over of homologs
13) 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?
E) either anaphase I or II
37) To visualize and identify meiotic cells at metaphase with a microscope, what would you look for?
E) tetrads all aligned at the cell's center
5) Which of the following defines a genome?
E) the complete set of an organism's genes