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AP bio ch. 10

Terms in this set (62)

Identify all possible products of meiosis in plant and animal life cycles.
Gametes (sperm and eggs) and sperms
Asexual reproduction generally __________.
produces offspring genetically identical to the parent
Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Biological systems have multiple processes, such as reproduction, that affect genetic variation. They are evolutionarily conserved and shared by various organisms. Which statement best represents the connection between reproduction and evolution?
Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.
Submit
In eukaryotes, genetic information is passed to the next generation by processes that include mitosis or meiosis. Which of the explanations identifies the correct process and supports the claim that heritable information is passed from one generation to another?
In asexual reproduction, a single individual is the sole parent and passes copies of its genes to its offspring without the fusion of gametes.
Two sister chromatids are joined at the centromere prior to meiosis. Which statement is correct?
Barring mutation, the two sister chromatids must be identical.
This chromosome has two chromatids, joined at the centromere. What process led to the formation of the two chromatids?
The two chromatids were formed by duplication of a chromosome.
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.
Which of the following descriptions correctly defines a genome?
the complete set of an organism's genes
Which of the following is the smallest unit that would contain a complete copy of the entire human genome?
one human somatic cell
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
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
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 from those in humans.
Which of the following cell types or organisms can utilize both mitosis and meiosis in the correct circumstances?
a unicellular alga
Which of the following statements best describes a karyotype?
a display of all of the chromosomes of a single cell
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
A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
Its gametes must have 23 chromosomes.
Which of these is a way that the sexual life cycle increases genetic variation in a species?
by allowing crossing over
Which of the following types of cells would be produced by meiosis?
a haploid animal cell
Which of the following describes a karyotype?
organized images of a cell's chromosomes
The human X and Y chromosomes
include genes that determine an individual's sex.
Which of the following is an example of alternation of generations?
A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).
Referring to a plant's sexual life cycle, which of the following processes leads directly to the formation of gametes?
gametophyte mitosis
Which of these statements is true?
Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a haploid (n), single-celled zygote.

In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY).

At sexual maturity, ovaries and testes produce diploid gametes by meiosis.

Sexual life cycles among different types of organisms are identical with respect to the relative timing of meiosis and fertilization.
In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY).
Eukaryotic sexual life cycles show tremendous variation. Which of the following elements do all sexual life cycles have in common?
I. alternation of generations
II. meiosis
III. fertilization
IV. gametes
V. spores
II, III, and IV
Which of the following is true of a species that has a chromosome number of 2n = 16?
Each cell has eight homologous pairs.
At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
metaphase
Which of the following is a true statement about sexual versus asexual reproduction?
In sexual reproduction, individuals transmit 50% of their genes to each of their offspring.
The following question refers to the essential steps in meiosis described below.
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
Which of the steps take(s) place in both mitosis and meiosis?
3
For the following question(s), match the key event of meiosis with the stages listed below.
I. prophase I
V. prophase II
II. metaphase I
VI. metaphase II
III. anaphase I
VII. anaphase III
V. telophase I
VIII. telophase II
Centromeres of sister chromatids disjoin and chromatids separate.
VII
The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division malfunctions, 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
If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following statements describes the contents of this cell?
It has half the amount of DNA of the cell that began meiosis.
Which of the following events might result in a human zygote with 45 chromosomes?
an error in either egg or sperm meiotic anaphase
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
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?
They have half the number of chromosomes and one-fourth the amount of DNA.
When does the synaptonemal complex disappear?
late prophase of meiosis I
Which of the following happens during meiosis I?
Homologous chromosomes of a pair are separated from each other.
Chromatids are separated from each other during which of the following processes?
during both mitosis and meiosis II
Which of the following events occurs in meiosis but not in mitosis?
synapsis of chromosomes
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 sister chromatids or homologous chromosomes can separate.
Which of the following structures is found in a pair of homologous chromosomes?
four sister chromatids
When we see chiasmata under a microscope, that lets us know that which of the following processes has occurred?
prophase I
To visualize and identify meiotic cells at metaphase I with a microscope, what would you look for?
pairs of homologous chromosomes all aligned at the cell's center
For the following question(s), match the key event of meiosis with the stages listed below.
I. prophase I
II. metaphase I
III. anaphase I
IV. telophase I
V. prophase II
VI. metaphase II
VII. anaphase II
VIII. telophase II
Homologous chromosomes are aligned at the equator of the spindle.
II
For the following question(s), match the key event of meiosis with the stages listed below.
I. prophase I
II. metaphase I
III. anaphase I
IV. telophase I
V. prophase II
VI. metaphase II
VII. anaphase II
VIII. telophase II
Synaptonemal complexes form or are still present.
I only
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
approximately 8.4 million
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Independent assortment of chromosomes during meiosis 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.
During which process does independent assortment of chromosomes occur?
during meiosis I only
Which of the following statements best describes how often crossing over occurs in humans?
at least 1-3 times per chromosome pair
When homologous chromosomes cross over, what is the result?
Specific proteins break the two strands of nonsister chromatids and re-join them.
Please use the following information to answer the question(s) below.

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.
Because the rotifers develop from eggs, but asexually, what can you predict?
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.
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.
If the DNA content of a diploid cell in the G1 phase of the cell cycle is represented by x, then the DNA content of the same cell at metaphase of meiosis I would be 2x. If we continued to follow the cell lineage, the DNA content of a cell at metaphase of meiosis II would be __________.
x
If the DNA content of a diploid cell in the G1 phase of the cell cycle is represented by x, then the DNA content of the same cell at metaphase of meiosis I would be __________.
2x
Homologous chromosomes move toward opposite poles of a dividing cell during __________.
meiosis I
A human cell containing 22 autosomes and a Y chromosome is __________.
a sperm
What number and types of chromosomes are found in a human somatic cell?
44 autosomes and 2 sex chromosomes
For what purpose(s) might a karyotype be prepared?

for prenatal screening, to determine if a fetus has the correct number of chromosomes

to determine whether a fetus is male or female

to detect the possible presence of chromosomal abnormalities such as deletions, inversions, or translocations

The first and second answers are correct.

The first three answers are correct.
Submit
The first three answers are correct.
In alternation of generations, what is the diploid stage of a plant that follows fertilization called?
sporophyte
How are sister chromatids and homologous chromosomes different from each other?
Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.
Mitosis results in the formation of how many cells; meiosis results in the formation of how many cells?
two diploid cells ... four haploid cells
Which of the following occurs during meiosis but not during mitosis?
Synapsis occurs.
What is crossing over?
the exchange of homologous portions of nonsister chromatids
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