Chapter 13 Bio

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) Homologous chromosomes are separated.

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) I only B) I and IV only C) I and VIII only D) II and VI only E) I, II, III, and IV only

A) I only

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) at most, 2 alleles for that gene

How does the sexual life cycle increase the genetic variation in a species? A) by allowing crossing over B) by allowing fertilization C) by increasing gene stability D) by conserving chromosomal gene order E) by decreasing mutation frequency

A) by allowing crossing over

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) late prophase of meiosis I

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) 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.

A) the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.

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? A) 2 B) 3 C) 5 D) 2 and 3 only E) 2, 3, and 5

B) 3

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) Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment. A) I B) II C) IV D) VI E) VIII

B) II

A cell divides to produce two daughter cells that are genetically different. A) The statement is true for mitosis only. B) The statement is true for meiosis I only. C) The statement is true for meiosis II only. D) The statement is true for mitosis and meiosis I. E) The statement is true for mitosis and meiosis II.

B) The statement is true for meiosis I only.

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

B) The statement is true for meiosis I only.

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) synapsis of chromosomes

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) two sets of sister chromatids that have synapsed

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) Privet cells cannot reproduce sexually. 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) Genes on a particular privet chromosome, such as the X, must be on a different human chromosome, such as number 18.

C) Genes of privet chromosomes are significantly different than those in humans.

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 and position of the centromere only. B) Length, centromere position, and staining pattern only. C) Length, centromere position, staining pattern, and traits coded for by their genes. D) Length, centromere position, staining pattern, and DNA sequences. E) They have nothing in common except they are X-shaped.

C) Length, centromere position, staining pattern, and traits coded for by their genes.

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

C) Specific proteins break the two strands and re-join them with their homologs.

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 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) They must be removed before anaphase can occur.

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

C) at least 1-2 per chromosome pair

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

C) cohesins are protected from cleavage at the centromere during meiosis I.

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

D) DNA stain and a light microscope

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) They have half the number of chromosomes and one-fourth the amount of DNA.

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) haploid, and the chromosomes are each composed of two chromatids.

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

D) prophase I

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

E) The statement is true for mitosis and meiosis 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 Centromeres of sister chromatids disjoin and chromatids separate. A) II B) III C) IV D) V E) VII

E) VII

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) about 8 million

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

E) tetrads all aligned at the cell's center