Chapter 13 Flashcards
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?
Clone the plant asexually to produce an identical one.
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?
Clone the plant asexually to produce an identical one.
The human genome is minimally contained in which of the following?
every human cell
In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true?
A plant species (privet shrubs) has 46 chromosomes per cell.
Which of the following is a true statement about sexual vs. asexual reproduction?
In sexual reproduction, individuals transmit 50% of their genes to each of their offspring
Which of the following defines a genome?
the complete set of an organism’s genes
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
metaphase
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 individual’s sex.
E) include only genes that govern sex determination.
include genes that determine an individual’s sex.
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 eight homologous pairs.
D) During the S phase of the cell cycle there will be 32 separate chromosomes.
E) A gamete from this species has four chromosomes.
Each cell has eight homologous pairs.
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 A) I, IV, and V B) I, II, and IV C) II, III, and IV D) II, IV, and V E) I, II, III, IV, and V
II, III, and IV
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.
At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
Referring to a plant's 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
gametophyte mitosis
Which of the following is an example of alternation of generations?
A) A grandparent and grandchild each have 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.
A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).
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
either anaphase I or II
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.
Its gametes must have 23 chromosomes.
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
63 chromosomes in 21 sets of 3
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
the ordering of human chromosome images
Which of the following best describes a karyotype?
A) a pictorial representation of all the genes for a species
B) a display of each of the chromosomes of a single cell
C) the combination of all the maternal and paternal chromosomes of a species
D) the collection of all the chromosomes in an individual organism
E) a photograph of all the cells with missing or extra chromosomes
a display of each of the chromosomes of a single cell
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.
B) It has the same number of chromosomes but each of them has different alleles than another cell from the same meiosis.
C) It has half the chromosomes but twice the DNA of the originating cell.
D) It has one-fourth the DNA and one-half the chromosomes as the originating cell.
E) It is identical in content to another cell from the same meiosis.
It has half the amount of DNA as the cell that began meiosis.
Which of the following can utilize both mitosis and meiosis in the correct circumstances? A) a haploid animal cell B) a diploid cell from a plant stem C) any diploid animal cell D) a plantlike protist E) an archaebacterium
a plantlike protist
Which of the following might result in a human zygote with 45 chromosomes?
A) an error in either egg or sperm meiotic anaphase
B) failure of the egg nucleus to be fertilized by the sperm
C) fertilization of a 23 chromosome human egg by a 22 chromosome sperm of a closely related species
D) an error in the alignment of chromosomes on the metaphase plate
E) lack of chiasmata in prophase I
an error in either egg or sperm meiotic anaphase
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.
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.
Length, centromere position, staining pattern, and traits coded for by their genes.
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.
haploid, and the chromosomes are each composed of two chromatids
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.
They have half the number of chromosomes and one-fourth the amount of DNA.
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
late prophase of meiosis I
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.
Homologous chromosomes are separated.
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.
The statement is true for meiosis I only.
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.
The statement is true for mitosis and meiosis II.
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.
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
synapsis of chromosomes
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
at most, 2 alleles for that gene
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.
They must be removed before anaphase can occur.
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.
cohesins are protected from cleavage at the centromere during meiosis I.
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
two sets of sister chromatids that have synapsed
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
prophase 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
DNA stain and a light microscope
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
tetrads all aligned at the cell’s center
- Formation of four new nuclei, each with half the chromosomes present in the parental nucleus
- Alignment of tetrads at the metaphase plate
- Separation of sister chromatids
- Separation of the homologs; no uncoupling of the centromere
- 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
Separation of sister chromatids
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
by allowing crossing over
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
about 8 million
