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115 Cards in this Set
- Front
- Back
When a DNA molecule doubles, a chromosome is then comprised of two joined
________. |
chromatids
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Prokaryotic DNA molecules are packaged by ________ proteins, which associate with
DNA. |
basic
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In general, the division of the cell, called ________, follows immediately upon mitosis.
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cytokinesis
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The bacteria have a short sequence called ________ where DNA synthesis begins.
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ori
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The bacteria have a short sequence called ________ where DNA synthesis ends.
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ter
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During prophase I of meiosis a unique event occurs that results in the formation of recombinant chromosomes. This event is termed ________. |
crossing over
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The structure present during mitosis that is composed of two identical DNA molecules complexed with proteins and joined at the centromere is called a ________.
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chromosome
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The stage of the cell cycle during which DNA replicates is called the ________.
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S phase
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________ is the fusion of two gametes.
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Fertilization
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During prometaphase, microtubules associate with specialized structures in the
centromere regions called ________. |
kinetochore
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Occasionally, a homologous chromosome pair will fail to separate during anaphase I of meiosis. The resulting cells, one of which lacks a copy of this chromosome while the other contains both members of the homologous pair, are called ________ cells.
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aneuploid
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During a process known as ________, a piece of one chromosome can break off and
become joined to a different chromosome. |
translocation
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The orderly distribution of genetic information occurs in prokaryotic cells by a process
known as ________. |
binary fission
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A cell with three homologous sets of chromosomes is called a ________ cell.
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triploid
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The heritable information of the cell is ________.
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DNA
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The process that ensures the genetic information is passed on to a cell's daughter cells is
________. |
mitosis
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The process that ensures that only one of each pair of chromosomes is included in a
gamete is ________. |
meiosis
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The main role of nucleosomes in eukaryotic cells is to ________ the DNA.
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package
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The G2 phase always follows ________.
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S phase
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The G in G1 and G2 is short for ________. |
Gap |
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The chromatin ________ during prophase. |
condenses |
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The milestone event that defines entry into prometaphase is ________. |
loss of the nuclear envelope
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In plants a ________ forms at the equatorial region of the cell
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cell plate
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The cell plate is derived from the ________ of the cell.
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Golgi apparatus |
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The "invisible thread" that pinches cells into two during cell division is made of
________and ________. |
actin; myosin
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A zygote usually has ________ copies of each chromosome.
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2
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A ________ is the number, form, and type of chromosomes found in a cell, usually
similar within species and different between species. |
karyotype
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A ________ is one of a pair of chromosomes having the same overall genetic
composition and sequence. |
homolog
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Nondisjunction causes the production of ________ cells.
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aneuploid
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Down syndrome can be caused by an extra chromosome ________. |
21
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During meiosis in a tetraploid or a triploid plant, more problems are expected in
________ plants. |
triploid
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During prokaryotic cell division, two chromosomes separate from each other and distribute into the daughter cells by A) attachments to microtubules. B) a mitotic spindle. C) repellent forces. D) attachment to separating membrane regions. E) All of the above |
D) Attachment to separating membrane regions
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Prokaryotic cells take at least __________ minute(s) to divide. A) 1 B) 2 C) 20 D) 200 E) 1000 |
C) 20
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Bacteria typically have __________ while eukaryotes have __________. A) one chromosome that is circular, many that are linear B) several chromosomes that are circular, many that are linear C) one chromosome that is linear, many that are circular D) two chromosome that are circular, eight that are linear E) None of the above |
A) one chromosome that is circular, many that are linear.
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Chromosomes contain large amounts of five different interacting proteins, all of which
are known as A) pentanes. B) hexosamines. C) histones. D) protein hormones. E) histamines. |
c) histones
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The appropriate decisions to enter the S phase and the M phase of the cell cycle depend
on a pair of biochemicals called |
B) Cdk's and cyclin
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Sex and reproduction A) are not the same thing. B) are identical. C) both involve combining genetic material from two cells. D) both involve the formation of new individuals. E) None of the above
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A) are not the same thing
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The molecules that make up a chromosome are A) DNA and RNA. B) DNA and proteins. C) proteins and lipids. D) nucleotides and nucleosides. E) proteins and phospholipids.
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B) DNA and proteins
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39. During mitosis and meiosis the chromatin compacts. Which of the following processes is
made easier by this compaction? A) The orderly distribution of genetic material to two new nuclei B) The replication of the DNA C) Exposing the genetic information on the DNA D) The unwinding of DNA from around the histones E) The disappearance of the nuclear membrane |
A) The orderly distribution of genetic material to two new nuclei |
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The basic structure of chromatin has sometimes been referred to as beads on a string of
DNA. These beads are called A) chromosomes. B) chromatids. C) supercoils. D) interphases. E) nucleosomes. |
E) nucleosomes
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DNA replication occurs A) during both mitosis and meiosis. B) only during mitosis. C) only during meiosis. D) during the S phase. E) during G2.
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D) during the S phase
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Around __________ base pairs wrap around each core particle in a __________ . A) 1000, solenoid B) 20000, chromosome C) 146, nucleosome D) 1000, chromosome E) 20,000, solenoid
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C) 146, nucleosome
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When cyclin binds Cdk, A) the cell transitions from G2 to S. B) kinase activation occurs. C) chromosomes condense. D) the cell quickly enters M phase. E) the cell begins apoptosis.
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B) kinase activation occurs
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Mature nerve cells are incapable of cell division. These cells are probably in A) G1. B) the S phase. C) G2. D) mitosis. E) meiosis.
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A) G1
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A cell cycle consists of A) mitosis and meiosis. B) G1, the S phase, and G2. C) prophase, metaphase, anaphase, and telophase. D) interphase and mitosis. E) meiosis and fertilization.
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D) Interphase and mitosis
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Evidence in yeast suggest that the maturation promoting factor of sea urchins was A) a cyclin. B) MFP. C) an S nuclease. D) a Cdk. E) a Cdk/cyclin phosphatase.
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D) a Cdk
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The cells of the intestinal epithelium are continually dividing, replacing dead cells lost from the surface of the intestinal lining. If you examined a population of intestinal
epithelial cells under the microscope, most of the cells would A) be in meiosis. B) be in mitosis. C) be in interphase. D) have condensed chromatin. E) b and d |
C) be in interphase
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DNA damage by UV radiation causes the synthesis of A) p53. B) DNA. C) Cdk. D) cyclin. E) p21.
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E) p21
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The uncondensed length of human DNA found in chromosomes is __________, whereas
a typical cell's is 10 µm in length. A) 5 µm B) 2 µm C) 2 meters D) 20 meters E) 2.54 inches |
C) 2 meters
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The products of mitosis are A) one nucleus containing twice as much DNA as the parent nucleus. B) two genetically identical cells. C) four nuclei containing half as much DNA as the parent nucleus. D) four genetically identical nuclei. E) two genetically identical nuclei.
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E) two genetically identical nuclei
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The mitotic spindle is composed of A) chromosomes. B) chromatids. C) microtubules. D) chromatin. E) centrosomes.
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C) microtubules
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Centrosomes are A) constricted regions of phase chromosomes. B) regions where microtubules polymerize. C) the central region of the same cell. D) the region where the membrane constricts during cytokinesis. E) part of cilia.
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B) regions where microtubules polymerize |
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When dividing cells are examined under a light microscope, chromosomes first become
visible during A) interphase. B) the S phase. C) prophase. D) G1. E) G2. |
C) prophase
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The structures that line up the chromosomes on the equatorial plate during metaphase are
called A) asters. B) polar and kinetochore microtubules. C) centrosomes. D) centrioles. E) histones. |
B) polar and kinetochore microtubules
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The microtubules of the mitotic spindle attach to a specialized structure in the centromere
region of each chromosome, called the A) kinetochore. B) nucleosome. C) equatorial plate. D) aster. E) centrosome. |
A) kinetochore
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After the centromeres separate during mitosis, the chromatids, now called __________,
move toward opposite poles of the spindle. A) centrosomes B) kinetochores C) half spindles D) asters E) daughter chromosomes |
E) daughter chromosomes
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In plant cells, cytokinesis is accomplished by the formation of a(n) A) aster. B) membrane furrow. C) equatorial plate. D) cell plate. E) spindle.
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D) cell plate
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The distribution of mitochondria between the daughter cells during cytokinesis A) is random. B) is directed by the mitotic spindle. C) is directed by the centrioles. D) results in all of the mitochondria remaining in the parent cell. E) occurs only during meiosis.
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A) is random
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Genetically diverse offspring result from A) mitosis. B) cloning. C) sexual reproduction. D) cytokinesis. E) anaphase.
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C) sexual reproduction
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During asexual reproduction, the genetic material of the parent is passed on to the
offspring by A) homologous pairing. B) meiosis and fertilization. C) mitosis and cytokinesis. D) karyotyping. E) chiasmata. |
C) mitosis and cytokinesis
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Meiosis can occur A) in all organisms. B) only when an organism is diploid. C) only in multicellular organisms. D) only in haploid organisms. E) only in single-celled organisms.
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B) only when an organism is diploid
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All zygotes are A) multicellular. B) diploid. C) animals. D) clones. E) gametes.
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B) diploid
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In all sexually reproducing organisms, the diploid phase of the life cycle begins at A) spore formation. B) gamete formation. C) meiosis. D) mitosis. E) fertilization.
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E) fertilization
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The members of a homologous pair of chromosomes A) are identical in size and appearance. B) contain identical genetic information. C) separate to opposite poles of the cell during mitosis. D) are found only in haploid cells. E) are present only after the S phase.
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A) are identical in size and appearance
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The diagnosis of Down syndrome is made by examining the individual's A) spores. B) karyotype. C) chromatin. D) nucleosomes. E) kinetochores.
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B) karyotype
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During meiosis, the sister chromatids separate during A) anaphase II. B) anaphase I. C) the S phase. D) synapsis. E) telophase II.
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A) anaphase II
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The exchange of genetic material between chromatids on homologous chromosomes
occurs during A) interphase. B) mitosis and meiosis. C) prophase I. D) anaphase I. E) anaphase II |
C) prophase I
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At the end of the first meiotic division, each chromosome consists of A) chiasmata. B) a homologous chromosome pair. C) four copies of each DNA molecule. D) two chromatids. E) a pair of polar microtubules.
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D) two chromatids
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The four haploid nuclei found at the end of meiosis differ from one another in their exact
genetic composition. Some of this difference is the result of A) cytokinesis. B) replication of DNA during the S phase. C) separation of sister chromatids at anaphase II. D) spindle formation. E) crossing over during prophase I. |
E) crossing over during prophase I
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Diploid cells of the fruit fly Drosophila have 10 chromosomes. How many chromosomes
does a Drosophila gamete have? A) 1 B) 2 C) 5 D) 10 E) 20 |
C) 5
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During meiosis I in humans, one of the daughter cells receives A) only maternal chromosomes. B) a mixture of maternal and paternal chromosomes. C) the same number of chromosomes as a diploid cell. D) a sister chromatid from each chromosome. E) one-fourth the amount of DNA in the parent nucleus.
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B) a mixture of maternal and paternal chromosomes
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The fact that most monosomies and trisomies are lethal to human embryos illustrates A) the importance of the orderly distribution of genetic material during meiosis. B) the exchange of genetic information during crossing over. C) the advantage of sexual reproduction to the survival of a population. D) that each chromosome contains a single molecule of DNA. E) that meiosis results in the formation of haploid gametes.
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A) the importance of the orderly distribution of genetic material during meiosis
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A triploid nucleus cannot undergo meiosis because A) the DNA cannot replicate. B) not all of the chromosomes can form homologous pairs. C) the sister chromatids cannot separate. D) cytokinesis cannot occur. E) a cell plate cannot form.
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B) not all of the chromosomes can form homologous pairs. |
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A bacterial cell gives rise to two genetically identical daughter cells by a process known
as A) nondisjunction. B) mitosis. C) meiosis. D) fission. E) fertilization. |
D) fission
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Which of the following is not part of sexual reproduction? A) The segregation of homologous chromosomes during gamete formation B) The fusion of sister chromatids during fertilization C) The fusion of haploid cells from a diploid zygote D) The reduction in chromosome number during meiosis E) The production of genetically distinct gametes during meiosis
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B) The fusion of sister chromatids during fertilization
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Chromatin condenses to form discrete, visible chromosomes A) early in G1. B) during S. C) during telophase. D) during prophase. E) at the end of cytokinesis.
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D) during prophase
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Chromosomes "decondense" into diffuse chromatin A) at the end of telophase. B) at the beginning of prophase. C) at the end of interphase. D) at the end of metaphase. E) only in dying cells.
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A) at the end of telophase
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Microtubules that form the mitotic spindle tend to originate from or terminate in A) centromeres and telomeres. B) euchromatin. C) centrioles and telomeres. D) the nuclear envelope. E) centrioles and centromeres (kinetochores).
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E) centrioles and centromeres (kinetochores) |
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Asexual reproduction produces genetically identical individuals because A) chromosomes do not have to replicate. B) it involves chromosome replication without cytokinesis. C) no meiosis or fertilization takes place. D) the only cell division that occurs is meiosis. E) the mitotic spindle prevents nondisjunction.
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C) no meiosis or fertilization takes place
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One difference between mitosis and meiosis I is that A) homologous chromosome pairs synapse during mitosis. B) chromosomes do not replicate in the interphase preceding meiosis. C) homologous chromosome pairs synapse during meiosis but not mitosis. D) spindles composed of microtubules are not required during meiosis. E) sister chromatids separate during meiosis but not mitosis.
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C) homologous chromosome pairs synapse during meiosis but not mitosis.
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Genetic recombination occurs during A) prophase of meiosis I. B) interphase preceding meiosis II. C) mitotic telophase. D) fertilization. E) formation of somatic cells.
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A) prophase of meiosis I
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The number of chromosomes is reduced to half during A) anaphase of mitosis and meiosis. B) meiosis II. C) meiosis I. D) fertilization. E) interphase.
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C) meiosis I
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The total DNA content of each daughter cell is reduced during meiosis because A) chromosomes do not replicate during the interphase preceding meiosis I. B) chromosomes do not replicate between meiosis I and II. C) half of the chromosomes from each gamete are lost during fertilization. D) sister chromatids separate during anaphase of meiosis I. E) chromosome arms are lost during crossing over.
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B) chromosomes do not replicate between meiosis I and II
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Many chromosome abnormalities (trisomies and monosomies) are not observed in the
human population because A) they are lethal and cause spontaneous abortion of the embryo early in development. B) all trisomies and monosomies are lethal early in childhood. C) meiosis distributes chromosomes to daughter cells with great precision. D) they are so difficult to count. E) the human meiotic spindle is self-correcting. |
A) they are lethal and cause spontaneous abortion of the embryo early in development.
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In a haploid organism, most mitosis occurs A) after fertilization and before meiosis. B) after meiosis and before fertilization. C) between meiosis I and II. D) during G1. E) in diploid cells.
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B) after meiosis and before fertilization
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The event in the cell division process that clearly involves microfilaments rather than
microtubules is A) chromosome separation during anaphase. B) movement of chromosomes to the metaphase plate. C) chromosome condensation during prophase. D) disappearance of the nuclear envelope during prophase. E) cytokinesis in animal cells. |
E) cytokinesis in animal cells
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Trisomies and monosomies can result from accidents that occur during meiosis called A) nondisjunctions. B) inversions. C) reciprocal translocations. D) recombinations. E) acrocentricities.
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A) nondisjunction
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Chromosome number is reduced during meiosis because the process consists of A) two cell divisions without any chromosome replication. B) a single cell division without any chromosome replication. C) two cell divisions in which half of the chromosomes are destroyed. D) two cell divisions and only a single round of chromosome replication. E) four cell divisions with no chromosome replication.
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A) two cell divisions without any chromosome replication
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Which of the following phases of the cell cycle is not part of interphase? A) M B) S C) G1 D) G2 E) G0
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A) M
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During mitotic anaphase, chromatids migrate A) from the poles of the cell toward the metaphase plate. B) from the metaphase plate toward the poles. C) toward the nuclear envelope. D) along with their sister chromatids toward one pole. E) along with the other member of the homologous pair toward the metaphase plate.
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B) from the metaphase plate toward the poles
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Which of the following does not occur during mitotic prophase? A) Disappearance of the nuclear envelope B) Chromosome condensation C) Migration of centrioles toward the cell poles D) Synapsis of homologous chromosomes E) Formation of the mitotic spindle
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D) Synapsis of homologous chromosomes
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Human males have __________ different types of chromosomes. A) 23 B) 24 C) 46 D) 48 E) 92
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B) 24
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Which of the following is not true of homologous chromosome pairs? A) They come from only one of the individual's parents. B) They usually contain slightly different versions of the same genetic information. C) They segregate from each other during meiosis I. D) They synapse during meiosis I. E) Each contains two sister chromatids at the beginning of meiosis I.
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A) They come from only one of the individual's parents.
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Which of the following is not true of sister chromatids? A) They arise by replication during S phase. B) They segregate from each other during each mitotic anaphase. C) They usually contain identical versions of the same genetic information. D) They segregate from each other during meiosis I. E) They are joined during prophase and metaphase at their common centromere.
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D) They segregate from each other during meiosis I.
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Chromatin consists of A) DNA and histones. B) DNA, histones, and many other nonhistone proteins. C) mostly RNA and DNA. D) RNA, DNA, and nonhistone proteins. E) DNA alone.
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B) DNA, histones, and many other nonhistone proteins.
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The DNA of an eukaryotic cell is A) double stranded. B) single stranded. C) circular. D) complex inverted. E) conservative.
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A) double stranded
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Nucleosomes are made of A) RNA. B) lipid. C) histones. D) chromatin. E) All of the above
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C) histones
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A cell that is postreproductive will remain in A) S. B) G1. C) G2. D) M. E) prophase.
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B) G1
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The kinetochore is made of A) protein. B) microtubules. C) DNA. D) a and b. E) All of the above
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E) All of the above
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The milestone that defines metaphase is when the chromosomes A) separate. B) come together. C) are at opposite poles. D) line up. E) cross over.
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D) line up
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The milestone that defines anaphase is when the chromosomes A) separate. B) come together. C) are at opposite poles. D) line up. E) cross over.
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A) separate
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The milestone that defines telophase is when the chromosomes A) separate. B) come together. C) are at opposite poles. D) line up. E) cross over.
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C) are at opposite poles
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The major drawback of asexual reproduction is A) that it takes too little time. B) the variation generated. C) it prevents change. D) it requires cytokinesis. E) the lack of variation among the progeny.
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E) the lack of variation among the progeny
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Haploid means: A) the genes are arranged haphazardly. B) containing only one copy of each chromosome. C) the process of meiosis. D) half again the number of chromosomes. E) All of the above
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B) containing only one copy of each chromosome
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A reduction step during meiosis is important because A) it returns the chromosome number to normal before fertilization. B) there is a mechanism for this. C) only one copy of each chromosome is necessary. D) otherwise chromosome copies would double each fertilization. E) fertilization requires this.
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D) otherwise chromosome copies would double each fertilization
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Interleukins and erythropoietin are A) growth factors. B) Cdk's. C) cyclins. D) antitumor agents. E) intracellular signaling molecules.
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A) growth factors
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Half of all human cancers have defective __________ associated with their cells. A) p53 B) p21 C) Cdk D) cyclin E) DNA polymerase
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A) p53
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Each diploid cell of a human female contains A) one of each type of chromosome. B) two of each type of chromosome. C) four of each type of chromosome. D) a total of 23 of each type of chromosome. E) a total of 46 of each type of chromosome.
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B) two of each type of chromosome
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The importance of synapsis and the formation of chiasmata is that A) reciprocal exchange of chromosomal sections occurs. B) the DNA on homologous chromosomes mix. C) as a result, an increase in the variation of progeny occurs. D) overt evidence is provided for maternal and paternal chromosomes mixing. E) All of the above
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E) All of the above
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A triploid plant has A) one extra chromosome. B) one extra set of chromosomes. C) three chromosomes. D) three times the chance of a monoploid. E) three attempts at ploidy.
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B) one extra set of chromosomes
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Nucleosomes are found A) only in interphase cells. B) only during mitosis. C) only during meiosis. D) in all chromatin. E) in the cytoplasm.
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D) in all chromatin
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The energy to move chromosomes during mitosis is provided by A) centrioles. B) DNA polymerization. C) migration of the centrosomes. D) formation of the cell plate. E) ATP.
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E) ATP
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During bacterial cell division, the two DNA molecules are separated by A) centrosomes. B) spindle fibers. C) nucleosomes. D) cell elongation. E) aneuploidy.
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D) cell elongation
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The process of programmed cell death is called A) necrosis. B) lysis. C) apoptosis. D) cell displacement. E) cellular suicide.
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C) apoptosis
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An indicator of programmed cell death is A) fragmented chromatin. B) swelling of the membrane. C) cell lysis. D) loss of transcription control. E) All of the above
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A) fragmented chromatin
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