front 1 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? | back 1 C) Clone the plant asexually to produce an identical one. |
front 2 2) Which of the following defines a genome? | back 2 E) the complete set of an organism's genes |
front 3 3) Which is the smallest unit containing the entire human genome? | back 3 A) one human somatic cell |
front 4 4) 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? | back 4 A) at most, 2 alleles for that gene |
front 5 5) Which of the following is a true statement about sexual vs. asexual reproduction? | back 5 B) In sexual reproduction, individuals transmit 50% of their genes to each of their offspring. |
front 6 6) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype? | back 6 B) Metaphase |
front 7 7) Which of the following is true of a species that has a chromosome number of 2n = 16? | back 7 C) Each cell has eight homologous pairs. |
front 8 8) 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 | back 8 C) II, III, and IV |
front 9 9) Which of these statements is false? | back 9 D) At sexual maturity, ovaries and testes produce diploid gametes by meiosis. |
front 10 10) Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes? | back 10 B) gametophyte mitosis |
front 11 11) Which of the following is an example of alternation of generations? | back 11 B) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte). |
front 12 12) The human X and Y chromosomes | back 12 D) include genes that determine an individual's sex. |
front 13 13) Which of these is a karyotype? | back 13 C) organized images of a cell’s chromosomes |
front 14 14) Mitosis is commonly found in all of the following except | back 14 A) a haploid animal cell. |
front 15 15) Which of these is a way that the sexual life cycle increases genetic variation in a species? | back 15 A) by allowing crossing over |
front 16 16) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? | back 16 E) Its gametes must have 23 chromosomes. |
front 17 17) 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? | back 17 B) 63 chromosomes in 21 sets of 3 |
front 18 18) Which of the following best describes a karyotype? | back 18 B) a display of each of the chromosomes of a single cell |
front 19 19) Which of the following can utilize both mitosis and meiosis in the correct circumstances? | back 19 D) a plantlike protist |
front 20 20) 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? | back 20 C) Genes of privet chromosomes are significantly different than those in humans. |
front 21 21) 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? | back 21 C) length, centromere position, staining pattern, and traits coded for by their genes |
front 22 22) To view and analyze human chromosomes in a dividing cell, which of the following is (are) required? | back 22 D) DNA staining and a light microscope |
front 23 23) 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? | back 23 E) either anaphase I or II |
front 24 24) 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? | back 24 A) It has half the amount of DNA as the cell that began meiosis. |
front 25 25) Which of the following might result in a human zygote with 45 chromosomes? | back 25 A) an error in either egg or sperm meiotic anaphase |
front 26 26) After telophase I of meiosis, the chromosomal makeup of each daughter cell is | back 26 D) haploid, and the chromosomes are each composed of two chromatids. |
front 27 27) How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? | back 27 D) They have half the number of chromosomes and one-fourth the amount of DNA. |
front 28 28) When does the synaptonemal complex disappear? | back 28 A) late prophase of meiosis I |
front 29 29) Which of the following happens at the conclusion of meiosis I? | back 29 A) Homologous chromosomes of a pair are separated from each other. |
front 30 30) Chromatids are separated from each other. | back 30 E) The statement is true for mitosis and meiosis II. |
front 31 31) Which of the following occurs in meiosis but not in mitosis? | back 31 B) synapsis of chromosomes |
front 32 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? | back 32 C) They must be removed before sister chromatids or homologous chromosomes can separate. |
front 33 33) Experiments with cohesins have found that | back 33 C) cohesins are protected from cleavage at the centromere during meiosis I. |
front 34 34) A pair of homologous chromosomes includes which of the following sets of DNA strands? | back 34 B) two sister chromatids that have synapsed |
front 35 35) When we see chiasmata under a microscope, that lets us know which of the following has occurred? | back 35 D) prophase I |
front 36 36) To visualize and identify meiotic cells at metaphase with a microscope, what would you look for? | back 36 E) pairs of homologous chromosomes all aligned at the cell's center |
front 37 I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 37) Homologous chromosomes are aligned at the equator of the spindle. | back 37 B) II |
front 38 I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 38) Synaptonemal complexes form or are still present. | back 38 A) I only |
front 39 39) Centromeres of sister chromatids disjoin and chromatids separate. I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II | back 39 E) VII |
front 40 1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus 2. Alignment of homologous chromosomes 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 40) Which of the steps take(s) place in both mitosis and meiosis? | back 40 B) 3 |
front 41 41) For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? | back 41 E) about 8 million |
front 42 42) Independent assortment of chromosomes is a result of | back 42 A) the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. |
front 43 43) Independent assortment of chromosomes occurs. | back 43 B) The statement is true for meiosis I only. |
front 44 44) Which of the following best describes the frequency of crossing over in mammals? | back 44 C) at least 1-2 per chromosome pair |
front 45 45) When homologous chromosomes cross over, what occurs? | back 45 C) Specific proteins break the two strands of nonsister chromatids and re-join them. |
front 46 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. 1) Because the rotifers develop from eggs, but asexually, what can you predict? | back 46 E) No males can be found. |
front 47 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. 2) How is natural selection related to sexual reproduction as opposed to asexual reproduction? | back 47 A) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction. |
front 48 1) A human cell containing 22 autosomes and a Y chromosome is | back 48 A) a sperm. |
front 49 2) Homologous chromosomes move toward opposite poles of a dividing cell during | back 49 B) meiosis I. |
front 50 3) 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 | back 50 D) 2x. |
front 51 4) If we continued to follow the cell lineage from question 3, then the DNA content of a single cell at metaphase of meiosis II would be | back 51 C) x. |
front 52 5) 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)? | back 52 D) 16 |