Chapter 10 Practice Test Flashcards
How many genes are present in the human genome?
tens of thousands
What is a locus?
the specific location of a gene along the length of a chromosome
Sexual and asexual reproduction are alike in that __________.
they can both occur in multicellular organisms
A clone is the product of __________.
asexual reproduction and mitosis (in asexually reproducing organisms)
A karyotype is __________.
a display of all of an individual’s chromosomes arranged in pairs
Fertilization produces __________.
a diploid zygote
Which, if any, of the following statements is true?
a) Haploid cells can divide by mitosis.
b) Diploid cells can divide by mitosis.
c) Diploid cells can divide by meiosis.
d) Haploid cells cannot divide by meiosis.
e) All of the listed responses are correct.
e) All of the listed responses are correct.
Which of the following is part of the life cycle called alternation of generations?
a) zygote
b) spores
c) multicellular haploid stage (gametophyte)
d) multicellular diploid stage (sporophyte)
e) All of the listed responses are correct.
e) All of the listed responses are correct.
The sexual cycle of the multicellular algal genus Fucus involves __________.
mitosis, meiosis, and fertilization
In sexually reproducing species, the chromosome number remains stable over time because __________ and __________ always alternate.
meiosis … fertilization
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
How many pairs of autosomes do humans have?
22
Sister chromatids __________.
are identical copies of each other formed during DNA synthesis
Humans have 46 chromosomes. This number of chromosomes will be found in __________.
liver cells (is a specific example, all somatic, or non-sex cells, is the correct answer)
When we say that an organism is haploid, we mean that __________.
its cells have a single set of chromosomes
What is the function of mitosis in humans?
multiplication of body cells that are genetically identical to the parent cell
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.
two … diploid
Nearly all life cycles have both haploid and diploid phases. Usually, the transition from haploid to diploid takes place __________.
at fertilization, when gametes fuse
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
______ results in cells that contain half the parental chromosome number.
meiosis
At the end of telophase I of meiosis and the first cytokinesis, there are __________.
two haploid cells
What is the result when a diploid cell undergoes meiosis?
four haploid cells
Synapsis occurs during __________.
prophase I
Which of the following occurs during anaphase II?
Sister chromatids separate and migrate toward opposite poles.
Which of the following occurs during anaphase I?
Homologs separate and migrate toward opposite poles, guided by the spindle apparatus.
What is the function of meiosis?
to make cells with a haploid (half that of the parents) number of chromosomes
Crossing over occurs during __________.
prophase I
Regions of chromosomes where nonsister chromatids cross over are called __________.
chiasmata
The synaptonemal complex __________.
physically connects homologous chromosomes during prophase I
Which event occurs only during prophase I of the first meiotic division?
Synapsis of homologous pairs occurs.
In a male mammal, every cell that undergoes meiosis gives rise to __________ sperm.
four
Which function makes meiosis lengthier and more complex than mitosis?
a) introducing genetic variation among the daughter cells
b) undergoing two rounds of cytokinesis
c) decreasing the chromosome number to haploid
d) ensuring that each daughter cell gets a single, complete set of chromosomes
e) All of the listed responses are correct.
e) All of the listed responses are correct.
Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is FALSE?
a) During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs.
b) During meiosis II, cohesion holds sister chromatids along their lengths as the second meiotic spindle forms.
c) Cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate.
b) During meiosis II, cohesion holds sister chromatids along their lengths as the second meiotic spindle forms.
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8?
16
What contributes to genetic variation in sexually reproducing species?
random fertilization, independent assortment, crossing over
In humans, the haploid number of chromosomes is 23. Independent assortment has the possibility of producing __________ different types of gametes.
2^23
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.
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 of obtaining a gamete in which all the chromosomes are paternal ones?
1/8
The major contribution of sex to evolution is that __________.
it increases genetic variation
Which of the following answers is NOT involved with or an outcome of crossing over?
a) the random alignment of homologous pairs of chromosome at metaphase I
b) formation of chromosomes containing paternal and maternal alleles
c) The DNA in two nonsister chromatids is broken by specific proteins at exact points.
d) Chiasmata indicate where crossing over is occurring between homologs.
e) All of the listed responses pertain to the process of crossing over.
a) the random alignment of homologous pairs of chromosome at metaphase I
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.
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
