chapter 13
1) A human cell containing 22 autosomes and a Y chromosome is A) a sperm. B) an egg. C) a zygote. D) a somatic cell of a male. E) a somatic cell of a female.
A
1) What is a genome? A) The complete complement of an organismʹs genes B) A specific set of polypeptides within each cell C) A specialized polymer of four different kinds of monomers D) A specific segment of DNA that is found within a prokaryotic chromosome E) An ordered display of chromosomes arranged from largest to smallest
A
28) When does the synaptonemal complex disappear? A) Late prophase of meiosis I B) During fertilization or fusion of gametes C) Early anaphase of meiosis I D) Mid-prophase of meiosis II E) Late metaphase of meiosis II
A
32) Which of the following happens at the conclusion of meiosis I? A) Homologous chromosomes are separated. B) The chromosome number per cell is conserved. C) Sister chromatids are separated. D) Four daughter cells are formed. E) The sperm cells elongate to form a head and a tail end.
A
4) Meiosis II is similar to mitosis in that A) sister chromatids separate during anaphase. B) DNA replicates before the division. C) the daughter cells are diploid. D) homologous chromosomes synapse. E) the chromosome number is reduced.
A
46) 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 B) Up to 18 chromosomes with that gene C) Up to 18 genes for that trait D) A haploid number of 9 chromosomes E) Up to, but not more than, 18 different traits
A
54) How does the sexual life cycle increase the genetic variation in a species? A) By allowing independent assortment of chromosomes B) By allowing fertilization C) By increasing gene stability D) By conserving chromosomal gene order E) By decreasing mutation frequency
A
56) 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 random distribution of the sister chromatids to the two daughter cells during anaphase II. D) the relatively small degree of homology shared by the X and Y chromosomes. E) All of the above
A
6) The human genome is minimally contained in which of the following? A) Every human cell B) Each human chromosome C) The entire DNA of a single human D) The entire human population E) Each human gene
A
15) Referring to a plant 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) Gametophyte meiosis D) Sporophyte mitosis E) Alternation of generations
B
16) Which of the following is an example of alternation of generations? A) A grandparent and grandchild each has dark hair, but the parent has blond hair. B) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte). C) A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote. D) A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization, which is immediately followed by meiosis. E) A diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to produce a tetraploid cell.
B
24) 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 in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with three chromatids D) 21 chromosome pairs and 21 unique chromosomes
B
3) Homologous chromosomes move toward opposite poles of a dividing cell during A) mitosis. B) meiosis I. C) meiosis II. D) fertilization. E) binary fission.
B
45) Which of the following occurs in meiosis but not in mitosis? A) Chromosome replication B) Synapsis of chromosomes C) Production of daughter cells D) Alignment of chromosomes at the equator E) Condensation of chromatin
B
49) A tetrad includes which of the following sets of DNA strands? A) Two single-stranded chromosomes that have synapsed B) Two sets of sister chromatids that have synapsed C) Four sets of sister chromatids D) Four sets of unique chromosomes E) Eight sets of sister chromatids
B
57) When pairs of homologous chromosomes separate during anaphase I, A) the maternal chromosomes all move to the same daughter cell. B) the sister chromatids remain attached to one another. C) recombination is not yet complete. D) the synaptonemal complex is visible under the light microscope.
B
9) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype? A) Prophase B) Metaphase C) Anaphase D) Telophase E) Interphase
B
11) Which of the following is true of a species that has a chromosome number of 2n = 16? A) The species is diploid with 32 chromosomes per cell. B) The species has 16 sets of chromosomes per cell. C) Each cell has 8 homologous pairs. D) During the S phase of the cell cycle there will be 32 separate chromosomes. E) A gamete from this species has 4 chromosomes.
C
12) 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) I, IV, and V B) I, II, and IV C) II, III, and IV D) II, IV, and V E) All of the above
C
14) In animals, meiosis results in gametes, and fertilization results in A) spores. B) gametophytes. C) zygotes. D) sporophytes. E) clones.
C
25) A karyotype results from which of the following? A) A natural cellular arrangement of chromosomes in the nucleus B) An inherited ability of chromosomes to arrange themselves C) The ordering of human chromosome images D) The cutting and pasting of parts of chromosomes to form the standard array E) The separation of homologous chromosomes at metaphase I of meiosis
C
38) You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase I cells on the slide? A) A visible nuclear envelope B) Separated sister chromatids at each pole of the cell C) Tetrads lined up at the center of the cell D) A synaptonemal complex E) A cleavage furrow
C
4) 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) Backtrack through her previous experiments to obtain another plant with the same traits. B) Breed this plant with another plant with much weaker traits. C) Clone the plant asexually to produce an identical one. D) Force the plant to self-pollinate to obtain an identical one. E) Add nitrogen to the soil of the offspring of this plant so the desired traits continue.
C
47) Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesions. Such molecules must have which of the following properties? A) They must persist throughout the cell cycle. B) They must be removed before meiosis can begin. C) They must be removed before anaphase can occur. D) They must reattach to chromosomes during G1. E) They must be intact for nuclear envelope reformation.
C
48) Experiments with cohesions have found that A) cohesions are protected from destruction throughout meiosis I and II. B) cohesions are cleaved from chromosomes at the centromere before anaphase I. C) cohesions are protected from cleavage at the centromere during meiosis I. D) a protein cleaves cohesions before metaphase I. E) a protein that cleaves cohesions would cause cellular death.
C
6) 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) 0.25x. B) 0.5x. C) x. D) 2x. E) 4x.
C
7) A geneʹs location along a chromosome is known as which of the following? A) Allele B) Sequence C) Locus D) Variant E) Trait
C
10) The human X and Y chromosomes A) are both present in every somatic cell of males and females alike. B) are of approximately equal size and number of genes. C) are almost entirely homologous, despite their different names. D) include genes that determine an individualʹs sex. E) include only genes that govern sex determination.
D
13) Which of these statements is false? A) In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. B) In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY). C) Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote. D) At sexual maturity, ovaries and testes produce diploid gametes by meiosis. E) Sexual life cycles differ with respect to the relative timing of meiosis and fertilization.
D
2) Which life cycle stage is found in plants but not animals? A) Gamete B) Zygote C) Multicellular diploid D) Multicellular haploid E) Unicellular diploid
D
2) Which of the following statements about genes is incorrect? A) Genes correspond to segments of DNA. B) Many genes contain the information needed for cells to synthesize enzymes and other proteins. C) During fertilization, both the sperm and the ovum contribute genes to the resulting fertilized egg. D) One gene only is used in a specific cell type. E) Genetic differences can result from changes in the DNA called mutations.
D
26) After telophase I of meiosis, the chromosomal makeup of each daughter cell is A) diploid, and the chromosomes are each composed of a single chromatid. B) diploid, and the chromosomes are each composed of two chromatids. C) haploid, and the chromosomes are each composed of a single chromatid. D) haploid, and the chromosomes are each composed of two chromatids. E) tetraploid, and the chromosomes are each composed of two chromatids.
D
27) 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 twice the amount of cytoplasm and half the amount of DNA. B) They have half the number of chromosomes and half the amount of DNA. C) They have the same number of chromosomes and half the amount of DNA. D) They have half the number of chromosomes and one-fourth the amount of DNA. E) They have half the amount of cytoplasm and twice the amount of DNA.
D
5) Asexual reproduction results in identical offspring unless which of the following occurs? A) Natural selection B) Cloning C) Crossing over D) Mutation E) Environmental change
D
5) 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) 0.25x. B) 0.5x. C) x. D) 2x. E) 4x.
D
53) Chiasmata are what we see under a microscope that let us know which of the following is occurring? A) Asexual reproduction B) Meiosis II C) Anaphase II D) Crossing over E) Separation of homologs
D
58) Natural selection and recombination due to crossing over during meiosis I are related in which of the following ways? A) Recombinants are usually selected against. B) Non-recombinant organisms are usually favored by natural selection if there is environmental change. C) Most recombinants reproduce less frequently than do non-recombinants. D) Recombinants may have combinations of traits that are favored by natural selection. E) Recombination does not affect natural selection.
D
22) 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) Metaphase I of one meiotic event C) Telophase II of one meiotic event D) Telophase I of one meiotic event E) Either anaphase I or II
E
23) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A) It must be human. B) It must be a primate. C) It must be an animal. D) It must be sexually reproducing. E) Its gametes must have 23 chromosomes.
E
3) Asexual reproduction and sexual reproduction differ in all but which of the following ways? A) Individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually transmit only 50%. B) Asexual reproduction produces offspring that are genetically identical to the parents, whereas sexual reproduction gives rise to genetically distinct offspring. C) Asexual reproduction involves a single parent, whereas sexual reproduction involves two. D) Asexual reproduction requires only mitosis, whereas sexual reproduction always involves meiosis. E) Asexual reproduction is utilized only by fungi and protists, whereas sexual reproduction is utilized only by plants and animals.
E
55) 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) 23 B) 46 C) 460 D) 920 E) About 8 million
E
8) What is a karyotype? A) The set of unique physical characteristics that define an individual B) The collection of all the mutations present within the genome of an individual C) The combination of chromosomes found in a gamete D) A system of classifying cell nuclei E) A display of every pair of homologous chromosomes within a cell, organized according to size and shape
E
