Capmbell Chapter 13
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 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.
B
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
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
homologous chromosomes
Chromosomes that have the same sequence of genes and the same structure
10) 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
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?
Genes of privet chromosomes are significantly different than those in humans.
Which of the following happens at the conclusion of meiosis I?
Homologous chromosomes are separated.
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.
A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
Its gametes must have 23 chromosomes.
When homologous chromosomes crossover, what occurs?
Specific proteins break the two strands and re-join them with their homologs.
How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?
They have half the number of chromosomes and one-fourth the amount of DNA
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?
They must be removed before anaphase can occur.
Which of the following best describes a karyotype?
a display of each of the chromosomes of a single cell
What can utilize both mitosis and meiosis
a plantlike protist
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
about 8 million
Which of the following might result in a human zygote with 45 chromosomes?
an error in either egg or sperm meiotic anaphase
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?
at most, 2 alleles for that gene
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?
either anaphase I or II
The human genome is minimally contained in which of the following?
every human cell
Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes?
gametophyte mitosis
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
haploid, and the chromosomes are each composed of two chromatids.
The human X and Y chromosomes
include genes that determine an individual's sex.
Homologous chromosomes move toward opposite poles of a dividing cell during
meiosis I.
At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
metaphase
Which life cycle stage is found in plants but not animals?
multicellular haploid
Meiosis II is similar to mitosis in that
sister chromatids separate during anaphase.
Which of the following defines a genome
the complete set of an organism's genes
karyotype results from which of the following?
the ordering of human chromosome images