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Chapter 12

Terms in this set (38)

A non-sex chromosome is _____.
-a karyotype
-a Y chromosome
-an autosome
-an X chromosome
an autosome
Homologous chromosomes _____.
-carry the same alleles
-are identical
-are found only in haploid cells
-carry the same genes
carry the same genes
In an organism in which 2n = 6, how many chromosomes will be in each gamete?
-6
-2
-12
-3
3
Chromosome number is reduced during _____.
-meiosis II
-S phase
-meiosis I
-G2 phase
meiosis I
In a haploid organism, how many different alleles can there be for each gene?
-one-half
-one
-two
-four
one
Crossing over occurs _____.
-during S phase
-during prophase of mitosis
-as sister chromatids separate in anaphase II
-during synapsis of homologous chromosomes
during synapsis of homologous chromosomes
Which of the following creates different combinations of maternal and paternal chromosomes in gametes?
-crossing over
-meiosis II
-independent assortment
-mitosis
independent assortment
Which of the following creates new combinations of alleles along one chromosome?
-Independent assortment
-mitosis
-meiosis II
-crossing over
crossing over
An advantage of sexual reproduction is hypothesized to be _____.
-the production of clones
-reducing genetic diversity
-increasing the chance that a parent will transmit all their genes to a an offspring
-avoiding the transmission of harmful alleles to offspring
avoiding the transmission of harmful alleles to offspring
Nondisjunction in meiosis produces _____.
-diploids
-aneuploids
-haploids
-zygotes
aneuploids
Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?
-DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid only in meiosis II.
-DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
-DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
-DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid only in meiosis II.
-DNA content is halved only in meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
Human gametes are produced by _____.
-mitosis
-asexual reproduction
-the cell cycle
-meiosis
-fertilization
mitosis
Normal human gametes carry _____ chromosomes.
-23 pairs of
-23
-46
-46 pairs of
-5
23
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.
-32
-64
-30
-16
-8
16
What is the ploidy of organisms that have two sets of chromosomes?
-3n
-2n
-4n
-n
2n
What information can not be obtained from an individual's karyotype?
-The number of autosomes in the individual
-The types of chromosomes present in the individual
-The ploidy of the individual
-The sequence of bases of a particular gene
The sequence of bases of a particular gene
True or false? A haploid organism has one pair of homologous chromosomes.
False
If a cell has 24 chromosomes, how many chromosomes would each of its four daughter cells have after meiosis?
-12
-24
-36
-six
12
Which of the following statements about meiosis and mitosis is true?
-Meiosis II is similar to mitosis in that sister chromatids of each chromosome separate.
-In meiosis II and mitosis, a diploid cell divides.
-In mitosis and meiosis I, homologous chromosomes move independently of each other.
-Each daughter cell produced during meiosis and mitosis is genetically identical to the parent cell.
Meiosis II is similar to mitosis in that sister chromatids of each chromosome separate.
Which structure is directly correlated with the production of genetic variability in the daughter cells produced during meiosis?
-Centromere
-Tetrad
-Synapsis
-Chiasma
Chiasma
What is the composition of a tetrad at the beginning of prophase I?
-Two pairs of homologous chromosomes
-Four different chromosomes
-One pair of homologous chromosomes
-Two sister chromatids
One pair of homologous chromosomes
Meiosis I produces _____ cells, each of which is _____.
-two... diploid
-four ... haploid
-two ... haploid
-two... identical to the other
-four ... diploid
two ... haploid
Meiosis II typically produces _____ cells, each of which is ____.
-four ... identical to the other
-four ... diploid
-two ... haploid
-two... diploid
-four ... haploid
four ... haploid
Synapsis occurs during _____.
-prophase I
-anaphase II
-metaphase II
-telophase I and cytogenesis
-prophase II
prophase I
Homologous chromosomes migrate to opposite poles during _____.
-metaphase II
-telophase II and cytokinesis
-prophase II
-anaphase I
-metaphase I
anaphase I
During _____ chromosomes align single file along the equator of a haploid cell.
-anaphase I
-telophase I and cytokinesis
-prophase I
-metaphase II
-metaphase I
metaphase II
At the end of _____ and cytokinesis there are four haploid cells.
-prophase I
-prophase II
-telophase II
-anaphase I
-interphase
telophase II
During _____ a spindle forms in a haploid cell.
-telophase I and cytokinesis
-prophase I
-anaphase II
-metaphase II
-prophase II
prophase II
Which of these individuals is a homozygous genotype?
-AG
-aG
-Gg
-AA
-Aa
AA
All the genes in a population are that population's _____.
-fitness
-Hardy-Weinberg
-phenotype
-genotype
-gene pool
gene pool
Genetic drift is a process based on _____.
-differential reproductive success correlated to the relationship between a phenotype and the environment
-emigration
-immigration
-the role of chance
-mutation
the role of chance
A mutation occurs when _____.
-some individuals leave more offspring than other individuals
-there is a change in the DNA sequence of a gene
-individuals leave a population
-population sizes are small
-individuals enter a population
there is a change in the DNA sequence of a gene
Every few years a giant axe chops off the head of every person who is over 6 feet tall. How will this affect the human population?
-Gene flow will increase.
-It will increase in number since shorter people use fewer resources than taller people.
-Genetic drift will play less of a role in the evolution of humans.
-The mutation rate will increase.
-Alleles that promote "tallness" will decrease in frequency.
Alleles that promote "tallness" will decrease in frequency.
Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.
-genetic drift
-disease
-natural selection
-mutation
-gene flow
genetic drift
The ease with which humans travel across the globe is likely to increase _____.
-mutation
-natural selection
-gene flow
-genetic drift
-all of these
gene flow
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
-prophase II
-anaphase I
-telophase II
-metaphase II
-metaphase I
metaphase I
Crossing over, resulting in an increase in genetic variation, occurs between _____.
-nonsister chromatids of nonhomologous chromosomes
-sister chromatids of homologous chromosomes
-sex cells and somatic cells
-nonsister chromatids of homologous chromosomes
-sister chromatids of nonhomologous chromosomes
nonsister chromatids of homologous chromosomes
In human gamete production there is an average of _____ crossover events per chromosome pair.
-5-6
-10+
-9-10
-2-3
-0-1
2-3
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