bio chapter 13
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)
16
a tetrad inclues which of the following sets of DNA strands
2 sets of sister chromatids that have synapsed
if the DNA content of a diploid cell in the g1 phase of the cell cycle in x, then the DNA content of the same cell at metaphase of meiosis I would be
2x
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?
63 chromosomes in 21 sets of 3
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
to view and analyze human chromosomes in a dividing cell which of the following is/are required
DNA stain and a light microscope
You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in Figure 13.3. Refer to the graph to answer the following questions. 56) Which sample might represent a zygote?
I
You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in Figure 13.3. Refer to the graph to answer the following questions. 55) Which sample might represent an animal cell in the G2 phase of the cell cycle
II
eukaryotic sexual life cycles show tremendous variation. What do all sexual life cycles have in common
II,III,IV
which of the following is an example of alternation of generations
a diploid plant produces by meiosis, a spore that gives rise to a multicellular, haploid pollen grain
Which of the following best describes a karyotype?
a display of each of the chromosomes of a single cell
In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true?
a plant species has 46 chromosomes per cell
Which of the following can utilize both mitosis and meiosis in the correct circumstances?
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
Centromeres of sister chromatids disjoin and chromatids separate.
anaphase II
Which of the following best describes the frequency of crossing over in mammals?
at least 1-2 per chromosome pair
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
How does the sexual life cycle increase the genetic variation in a species?
by allowing crossing over
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
Experiments with cohesins have found that
cohesins are protected from cleavage at the centromere during meiosis I
Assuming that the eggs are diploid, tetraploid, or partially tetraploid, what mechanism may still occur without fertilization?
crossing over of homologs
which of the following is true of a species that has a chromosome number of 2n=16
each cell has 8 homologous pairs
A female with a paternal set of one orange and one long gene chromosome and a maternal set comprised of one blue and one short gene chromosome is expected to produce which of the following types of eggs after meiosis?
each egg has a 1/4 change of having either blue long, blue short, orange long, orange short combinations
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 plants sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes
gametophyte mitosis
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
after telophase I of meiosis, the chromosomal makeup of each daughter cell lis
haploid, chromosomes are composed of two chromatids
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
the human x and y chromosomes
include genes that determine an individuals sex
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?
it has half the amount of DNA as the cell that began meiosis
A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
its gametes must have 23 chromosomes
When does the synaptonemal complex disappear
late prophase of meiosis I
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?
length, centromere position, staining pattern, and traits coded for by their genes
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
Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment.
metaphase I
which life cycle stage is found in plants but not animals
multicellular haploid
Since the rotifers develop from eggs, but asexually, what can you predict?
no males can be found
A certain female's number 12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene. As cells in her ovaries undergo meiosis, her resulting eggs (ova) may have which of the following?
one chromosome 12 with one blue gene and one chromosome 19 with one long gene
If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types?
one half blue short and one half orange short gene eggs
Synaptonemal complexes form or are still present
prophase I
when we see chiasmata under a microscope, that lets us know which of the following has occurred
prophase 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?
separation of sister chromatids
How is natural selection related to sexual reproduction as opposed to asexual reproduction?
sexual reproduction results in many new gene combinations some of which will lead to differential reproduction
meiosis II is similar to mitosis in that
sister chromatids separate during anaphase
When homologous chromosomes crossover, what occurs?
specific proteins break the two strands rejoin them with their homologs
A human cell containing 22 autosomes and a Y chromosome is
sperm
In part III of Figure 13.1, the progression of events corresponds to which of the following series?
sporophyte, meiosis, spore, mitosis, gametophyte, mitosis, gametes, fertilization
Which of the following occurs in meiosis but not in mitosis
synapsis of chromosomes
to visualize and identify meiotic cells at metaphase with a microscope which of the following is required
tetrads all aligned at the cells center
which of the following defines a genome
the complete set of an organisms genes
A karyotype results from which of the following? A) a natural cellular arrangement of chromosomes in the nucleus
the ordering of human chromosome images
independent assortment of chromosomes is a result of
the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.
In a life cycle such as that shown in part III of Figure 13.1, if the zygote's chromosome number is 10, which of the following will be true?
the sporophytes chromosome number per cell is 10 and the gametophytes is 5
a cell divides to produce two daughter cells that are genetically different.
the statement is true for meiosis I only
independent assortment of chromosomes occurs
the statement is true for meiosis I only
chromatids are separated from each other
the statement is true for mitosis and meiosis II
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 occurr
In these asexual rotifers, how does variation occur without meiosis and fertilization?
variation is caused by mutation and maintained by selection
if the dna content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of a single cell at metaphase of meiosis II would be
x