exam 3 chapter 6 – Flashcards

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What term describes a harmless, noncancerous or precancerous tumor?
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benign
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Which term describes a cancerous tumor?
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oncogenic
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What is the name of the process by which cancer cells break off of tumors and spread to other parts of the body?
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metastasis
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____ is the cause of about one-third of all cancer deaths.
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smoking tobacco
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The process by which cells of a malignant tumor can break away and start new cancers at distant locations is called ________.
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metastasis
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Cancer cells within which of the following biopsy samples would be the best indicator that the cancer has metastasized and is circulating through the bloodstream?
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lymph node
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Which of the following is not a known carcinogen?
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pet dander
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Free radicals remove ________ from other molecules.
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electrons
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Which of the following can neutralize dangerous free radicals within the body?
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antioxidants from dietary fruits and vegetables
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Which of the following is a risk factor for colon cancer?
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advanced age
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What are the two halves of a duplicated chromosome called?
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sister chromatids
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Consider a strand of DNA with the sequence GAATTCGGCA. What is the sequence of the complementary strand?
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CTTAAGCCGT
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What is the name for the region toward the middle of a replicated chromosome where sister chromatids are connected?
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centromere
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Which of the following is a feature of DNA?
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The backbone of each strand is composed of alternating sugar and phosphate groups.
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In a certain species of animal, 33% of the bases in its DNA are A. What percent of the bases are C?
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17%
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The two halves of a duplicated chromosome are called ________ (two words).
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sister chromatids
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________ (two words) is the enzyme that assists in DNA synthesis.
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DNA polymerase
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In a bacterial species, 20% of the bases in its DNA are C. What percent of the bases are G?
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20%
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The term "semiconservative replication" refers to the fact that
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the DNA molecule includes a parental strand and newly created DNA strand.
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Nucleotides in opposing strands of DNA that bind to each other are called
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complementary.
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The scientists that first described the structure of DNA were
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Watson and Crick.
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Bacteria are single cells that replicate themselves by binary fission, resulting in genetically identical daughter cells. These cells undergo
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asexual reproduction.
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If a double-stranded DNA molecule is like a twisted rope ladder with handrails and steps, what would the steps in the ladder represent?
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nitrogenous bases
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DNA polymerase moves along the length of the unwound helix, starting at the end of one strand and finishing at the end of the other strand. As shown in this figure, what is the result of this phenomenon?
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The DNA polymerase moves toward the unwound helix on one strand of DNA and away from it on the other strand.
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Which type of cell division produces daughter cells that are identical to the original cell?
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mitosis in animals
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Which of the following is a phase that occurs during mitosis?
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metaphase
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Which of the following is the correct order of events in the cell cycle?
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G1, S, G2, mitosis, cytokinesis
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During which part of mitosis does the nuclear envelope break down?
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prophase
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Which of the following is the correct order of events in mitosis?
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prophase, metaphase, anaphase, telophase
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Consider a cell that underwent mitosis but not cytokinesis. The result would be
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a cell with two nuclei.
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A cell plate forms during which process?
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cytokinesis in a plant cell
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Which carbohydrate is used to create the cell wall during cytokinesis in plant cells?
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cellulose
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During which phase of mitosis are the replicated chromosome aligned in the middle of the cell?
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metaphase
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During which phase of mitosis does the cytoplasm divide?
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telophase
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During which phase of mitosis do sister chromatids separate to opposite poles of the cell?
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anaphase
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Most cells spend most of their time in which phase?
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interphase
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Which of the following cells spends the most time in interphase?
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nerve cells in the brain
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Why do chromosomes resemble the letter X when viewed during metaphase?
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Because there are two sister chromatids joined at a point in the middle (the centromere).
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Most organelles duplicate during
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the G1 phase of interphase.
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Microtubules connect centrioles to ________ during mitosis.
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centromeres
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During the metaphase checkpoint, the cell checks whether
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its chromosomes are properly attached to microtubules.
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What is the difference between oncogenes and proto-oncogenes?
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Proto-oncogenes encode proteins that help a cell divide under favorable conditions; oncogenes encode proteins that help a cell divide under unfavorable conditions.
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A gene that encodes a protein necessary for a cell to stop at checkpoints is an example of a(n)
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tumor-suppressor gene.
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What is the process by which a tumor attracts and redirects blood vessels to keep it supplied with O2 and nutrients?
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angiogenesis
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Which of the following is a common feature of cancer cells?
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metastasis
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The multiple-hit model of cancer means that
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multiple mutations are required to cause most forms of cancer.
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________ are places in the cell cycle where proteins survey the cell to make sure that conditions for a favorable cell division have been met.
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Checkpoints
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Which of the following is a protein that acts as a tumor suppressor by fixing damaged DNA in cancerous cells?
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BRCA2
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Mutations of the gene that encodes p53 result in
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damaged DNA proceeding through mitosis.
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The surgical removal of cells, tissue, or fluid that will be analyzed to determine whether they are cancerous is called a ________.
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biopsy
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The most common type of cancer that people in the United States die from is
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lung cancer.
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Most forms of chemotherapy target which feature of cancer cells?
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cell division
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Radiation therapy works primarily by
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damaging DNA in cells so that cells can no longer grow and divide.
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A scientist who observes cancer cells under a microscope would likely see
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disorganized cells.
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A ________ is a surgical instrument used to perform biopsies.
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laparoscope
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Elevated CA125 in a patient's blood may indicate ovarian cancer. However, routine screening of CA125 levels is not practical due to which of the following reasons?
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CA125 levels vary among individuals.
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The members of a pair of nonsex chromosomes are called
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homologous chromosomes.
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Different versions of the same gene are called
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alleles.
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Normal sperm or egg cells in a human
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have one copy of each chromosome.
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Tetraploid organisms have four copies of each chromosome instead of the two copies that humans have. How many copies of each chromosome end up in a gamete produced by a tetraploid organism?
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2
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A normal human cell containing 22 autosomes and a Y chromosome is a(n)
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sperm cell.
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A normal human cell containing 44 autosomes and two X chromosomes is a(n)
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somatic cell of a female.
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Homologous chromosomes separate during
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meiosis I.
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Sister chromatids separate during
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meiosis II and mitosis.
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Crossing over occurs during
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prophase I of meiosis I.
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Genes that are located on the same chromosome are called
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linked genes.
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How does crossing over increase genetic diversity?
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Crossing over increases the number of distinct combinations of genes that may be present in a gamete.
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_______ are specialized cells (egg cells and sperm cells, for example) used for sexual reproduction.
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Gametes
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Which of these conditions is caused by nondisjunction of autosomal chromosomes?
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Trisomy 21 or Down syndrome
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Mutations are only passed from parent to child if the mutation occurs in the gonads that will be used to produce
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a gamete.
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