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.
2) Which of the following defines a genome?
E) the complete set of an organism's genes
3) Which is the smallest unit containing the entire human genome?
A) one human somatic cell
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?
A) at most, 2 alleles for that gene
5) 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.
6) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
B) Metaphase
7) Which of the following is true of a species that has a chromosome number of 2n = 16?
C) Each cell has eight homologous pairs.
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
C) II, III, and IV
9) Which of these statements is false?
D) At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
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?
B) gametophyte mitosis
11) 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).
12) The human X and Y chromosomes
D) include genes that determine an individual's sex.
13) Which of these is a karyotype?
C) organized images of a cell’s chromosomes
14) Mitosis is commonly found in all of the following except
A) a haploid animal cell.
15) Which of these is a way that the sexual life cycle increases genetic variation in a species?
A) by allowing crossing over
16) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
E) Its gametes must have 23 chromosomes.
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?
B) 63 chromosomes in 21 sets of 3
18) Which of the following best describes a karyotype?
B) a display of each of the chromosomes of a single cell
19) Which of the following can utilize both mitosis and meiosis in the correct circumstances?
D) a plantlike protist
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?
C) Genes of privet chromosomes are significantly different than those in humans.
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?
C) length, centromere position, staining pattern, and traits coded for by their genes
22) To view and analyze human chromosomes in a dividing cell, which of the following is (are) required?
D) DNA staining and a light microscope
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?
E) either anaphase I or II
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?
A) It has half the amount of DNA as the cell that began meiosis.
25) Which of the following might result in a human zygote with 45 chromosomes?
A) an error in either egg or sperm meiotic anaphase
26) After telophase I of meiosis, the chromosomal makeup of each daughter cell is
D) haploid, and the chromosomes are each composed of two chromatids.
27) 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.
28) When does the synaptonemal complex disappear?
A) late prophase of meiosis I
29) Which of the following happens at the conclusion of meiosis I?
A) Homologous chromosomes of a pair are separated from each other.
30) Chromatids are separated from each other.
E) The statement is true for mitosis and meiosis II.
31) Which of the following occurs in meiosis but not in mitosis?
B) synapsis of chromosomes
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 sister chromatids or homologous chromosomes can separate.
33) Experiments with cohesins have found that
C) cohesins are protected from cleavage at the centromere during meiosis I.
34) A pair of homologous chromosomes includes which of the following sets of DNA strands?
B) two sister chromatids that have synapsed
35) When we see chiasmata under a microscope, that lets us know which of the following has occurred?
D) prophase I
36) To visualize and identify meiotic cells at metaphase with a microscope, what would you look for?
E) pairs of homologous chromosomes all aligned at the cell's center
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.
B) II
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.
A) I only
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
E) VII
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?
B) 3
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?
E) about 8 million
42) 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.
43) Independent assortment of chromosomes occurs.
B) The statement is true for meiosis I only.
44) Which of the following best describes the frequency of crossing over in mammals?
C) at least 1-2 per chromosome pair
45) When homologous chromosomes cross over, what occurs?
C) Specific proteins break the two strands of nonsister chromatids and re-join them.
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?
E) No males can be found.
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?
A) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.
1) A human cell containing 22 autosomes and a Y chromosome is
A) a sperm.
2) Homologous chromosomes move toward opposite poles of a dividing cell during
B) meiosis I.
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
D) 2x.
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
C) x.
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)?
D) 16