Chapter 13- Principles of Biology
In a diploid set of chromosomes, one member of each pair of homologous chromosomes is derived from the father (paternal), and the other comes from the mother (maternal). If 2n = 6, what is the probability that a particular gamete will contain only paternal chromosomes?
1/8
Ignoring crossover events, how many kinds of gametes can be produced by an organism with a diploid number of 8?
16
How many pairs of autosomes do humans have?
22
In humans, the haploid number of chromosomes is 23. Independent assortment has the possibility of producing __________ different types of gametes.
223
An organism has a haploid chromosome number n = 4. How many tetrads will form during meiosis?
4
The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?
44
In a diploid cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.
5
Fertilization produces __________.
A diploid zygote
A human cell containing 22 autosomes and a Y chromosome is
A sperm
Which, if any, of the following statements is true?
All of the above responses are correct.
Which function makes meiosis lengthier and more complex than mitosis?
All of the listed responses are correct.
Which of the following is part of the life cycle called alternation of generations?
All of the listed responses are correct.
Which of the following statements reflects an advantage that sexual reproduction likely provides over asexual reproduction?
Although energetically more costly than asexual reproduction, sexual reproduction leads to different combinations of alleles that could provide adaptability in a changing environment.
A life cycle in which the only multicellular form is haploid is most typical of __________.
Fungi
Which of the following occurs in meiosis, but NOT mitosis?
Homologous chromosomes separate.
Which of the following occurs during anaphase I?
Homologs separate and migrate toward opposite poles.
Which of the following results in cells that contain half the parental chromosome number?
Meiosis
Homologous chromosomes move toward opposite poles of a dividing cell during
Meiosis I
Which life cycle stage is found in plants but not animals?
Multicellular Haploid
Crossing over occurs during __________.
Prophase I
Synapsis occurs during __________.
Prophase I
Which of the following occurs during anaphase II?
Sister chromatids separate and migrate toward opposite poles.
Meiosis II is similar to mitosis in that
Sister chromatids separate during anaphase
Which event occurs only during prophase I of the first meiotic division?
Synapsis of homologous pairs occurs.
The diploid number of chromosomes in a certain animal is 8 (2n = 8). How do the four pairs of homologous chromosomes align and separate during meiosis?
They align and assort independently to form any of 16 different combinations.
Which of the following statements about homologous chromosomes is correct?
They have genes for the same traits at the same loci.
At the end of telophase I of meiosis and the first cytokinesis, there are __________.
Two haploid cells
A karyotype is __________.
a photograph of all the chromosomes in a single cell from an individual
Sister chromatids __________.
are identical copies of each other formed through DNA synthesis
A clone is the product of __________.
asexual reproduction and mitosis
Nearly all life cycles have both haploid and diploid phases. Usually, the transition from haploid to diploid takes place __________.
at fertilization, when gametes fuse
Regions of chromosomes where nonsister chromatids cross over are called __________.
chiasmata
Cytokinesis is the __________.
division of the cytoplasm to create two cells
What is the typical result when a diploid cell has completed meiosis?
four haploid cells
Spores and gametes are different in that __________.
gametes can fuse to form a zygote, but spores can develop into independent organisms without first forming a zygote
The major contribution of sex to evolution is that __________.
it provides a method to increase genetic variation
When we say that an organism is haploid, we mean that __________.
its cells have a single set of chromosomes
Humans have 46 chromosomes. This number of chromosomes will be found in __________.
liver cells
In sexually reproducing species, the chromosome number remains stable over time because __________ and __________ always alternate.
meiosis ... fertilization
The sexual cycle of the diploid, multicellular algal genus Fucus involves __________.
mitosis, meiosis, and fertilization
Which of the following is a function of mitosis in humans?
multiplication of body cells
Unless the chromosomes were stained to show band patterns, a karyotype would be LEAST likely to show which of the following?
part of a chromosome turned around
The synaptonemal complex __________.
physically connects homologous chromosomes during prophase I
Which of the following contributes to genetic variation in sexually reproducing species?
random fertilization, independent assortment, crossing over
Although __________ is nearly universal among animals, bdelloid rotifers __________.
sexual reproduction ... reproduce asexually but can increase genetic variation present in a population by means of the uptake of DNA from other rotifers
How many genes are present in the human genome?
tens of thousands
What is a locus?
the precise location of a gene on a chromosome
hich of the following answers is NEITHER involved with crossing over NOR an outcome of crossing over?
the random alignment of homologous pairs of chromosomes at metaphase I
Sexual and asexual reproduction are alike in that __________.
they can both occur in multicellular organisms
What is the function of meiosis?
to make cells with a haploid (half that of the parents) number of chromosomes
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.
two ... diploid
