MDC Chapter 6 – Flashcards
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The phase immediately following Gap 1 in the eukaryotic cell cycle is _______.
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DNA synthesis
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Cancer cells differ from normal cells in two important aspects. They are:
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indefinite cell division and the loss of contact inhibition.
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In multicellular organisms, cells that undergo mitotic division but not meiotic division are called _____ cells.
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Somatic
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Which of the following is TRUE about sex determination in humans?
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The father's sperm determines the gender of a baby.
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What type of chromosomal abnormality leads to the phenotype known as Down syndrome?
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trisomy 21
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After replication, the region of contact between sister chromatids, which occurs near the center of the two chromosome strands is called the _____________.
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centromere
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Mitosis results in:
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daughter cells with the same number and composition of chromosomes.
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Which process is necessary to prevent the doubling of genome size during sexual reproduction?
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Meiosis
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In some species, sex is determined by environmental, rather than genetic, factors. This is true of:
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turtles.
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The human karyotype ___________.
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reveals the gender of the individual can reveal whether non-disjunction occurred in an egg or a sperm can be made from cells gathered by amniocentesis can be made from placental tissue
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Without histones, eukaryotic DNA most likely would be:
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much longer than it is.
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Joseph went to a copy center and used a copy machine to make a duplicate set of 46 pages. Joseph then stapled every copied sheet to its original. This is similar to how a cell replicates its chromosomes in mitosis. For what reason would a cell do something similar during mitosis?
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to keep the copies and originals organized for later separation
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Sister chromatids are:
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identical molecules of DNA resulting from replication.
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Which of the following explains the fact that the Y chromosome carries nonessential information?
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Women don't have a Y chromosome and are not genetically disadvantaged.
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Healthy individuals may have just one sex chromosome, as long as it is an X chromosome. Why can't a person survive with a Y chromosome and no X chromosome?
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The X chromosome has a full complement of genetic material, much of which is vital to life; the Y chromosome is missing the vast majority of these genes.
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Which of the following statements about telomeres is INCORRECT?
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They are slightly shorter in prokaryotic cells than in eukaryotic cells.
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The float in a toilet tank stops the filling of the tank when the water reaches a certain level. If this float is damaged so that it sinks instead, the water would overflow the tank after a flush. This scenario is similar to which of the following cellular concepts?
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loss of contact inhibition
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Which of the following is TRUE about meiosis in men and women?
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Sperm production results in four cells from one starting cell; for eggs, only one egg results from one starting cell.
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How many sex chromosomes does the normal human female inherit from her mother?
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1
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Which of the following is TRUE about prokaryotic reproduction?
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A single circular DNA helix is replicated into two identical circular DNA helices.
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The rate at which mitosis occurs varies dramatically for different types of cells. The most rapid cell division occurs:
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in the blood and the cells lining the various tissues of organs.
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Which of the following is the BEST definition of a homologous chromosome?
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one of two chromosomes of the same length and type inherited from a father or mother
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Which of the following is NOT a disadvantage of sexual reproduction?
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Variability among offspring enables parents to produce a range of offspring, any one of which may be suitable to changes in the environment.
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Which of the following is the direct product of DNA replication?
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Two sister chromatids
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If a cell containing 10 chromosomes divides by mitosis, how many daughter cells will be produced?
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2
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Binary fission is to asexual reproduction as __________ is to __________.
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dividing into two; genetically identical offspring
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Which of the following does NOT contribute to variability of the offspring in sexual reproduction?
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A brother and a sister producing children together
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Sister chromatids line up at the center of the cell during which phase of mitosis?
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Metaphase
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Which is NOT true about a pair of homologous chromosomes?
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One of the two homologous chromosomes is produced by the cell during DNA synthesis phase.
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The human genome comprises:
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46 chromosomes.
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Telomeres have been directly linked to aging in humans. If scientists were able to develop treatments that could reverse the shortening of telomeres, would they be able to reverse the aging of humans?
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No, cells that have lost normal telomere function are cancerous.
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Odometer is to an old, rusty car as __________ is to __________.
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telomere; a cell after 50 cell divisions
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Using a light microscope, it is easiest to see chromosomes:
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during mitosis and meiosis because the condensed chromosomes are thicker and therefore more prominent.
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How does crossing over introduce variation in meiosis?
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It positions alleles next to each other that previously were not together.
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If DNA replication occurs by unwinding and rebuilding, then:
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the two resulting DNA molecules each contain one original strand and one new strand.
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During which stage of the mitotic cell cycle do the chromosomes decondense back to strands of chromatin and each set of separated genetic material becomes enclosed in a nuclear envelope to form two daughter nuclei?
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telophase
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Chromosomes wind up, chromosomes line up in the middle of the cell, sister chromatids separate, cytokinesis occurs
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Which of the following places the events of mitosis into the CORRECT order?
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A part of the cytoskeleton of a cell, formed in prophase (in mitosis) or in prophase I (in meiosis), from which extend fibers that organize and separate the sister chromatids is called the ________.
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spindle
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The spindle begins to assemble at which phase of the mitotic cell cycle?
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prophase
