Ch 14 homework – Flashcards
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Who demonstrated that DNA is the genetic material of the T2 phage?
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Hershey and Chase
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The radioactive isotope 32P labels the T2 phage's _____.
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DNA
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Hershey and Chase used _____ to radioactively label the T2 phage's proteins.
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35S
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After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material.
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labeled DNA, DNA
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In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
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thymine, cytosine
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Short segments of newly synthesized DNA are joined into a continuous strand by _____.
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ligase
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After DNA replication is completed, _____.
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each new DNA double helix consists of one old DNA strand and one new DNA strand
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The action of helicase creates _____.
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replication forks and replication bubbles
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Why is the new DNA strand complementary to the 5' to 3' strands assembled in short segments?
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DNA polymerase can assemble DNA only in the 5' to 3' direction
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An old DNA strand is used as a _____ for the assembly of a new DNA strand.
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template
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The first step in the replication of DNA is catalyzed by _____.
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helicase
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The synthesis of a new strand begins with the synthesis of a(n) _____.
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RNA primer complementary to a preexisting DNA strand
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What catalyzes DNA synthesis?
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DNA polymerase
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Which of the following statements about DNA synthesis is true?
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Primers are short sequences that allow the initiation of DNA synthesis.
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Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis?
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Phosphate groups
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Which of the following enzymes creates a primer for DNA polymerase?
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Primase
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Which of the following statements about Okazaki fragments in E. coli is true?
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They are formed on the lagging strand of DNA.
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Which of the following enzymes is important for relieving the tension in a helix as it unwinds during DNA synthesis?
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Topoisomerase
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True or false? Single-stranded DNA molecules are said to be antiparallel when they are lined up next to each other but oriented in opposite directions.
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True
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Which of these is a difference between a DNA and an RNA molecule?
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DNA is double-stranded, whereas RNA is single-stranded.
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Which of these nitrogenous bases is found in DNA but not in RNA?
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thymine
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In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.
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1', 5'
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Nucleic acids are assembled in the _____ direction.
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5' to 3'
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Research indicates that the best estimate of your age is from ______.
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markers in your cells
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The cells examined from the 2,400 people in this study were from ______.
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blood
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Which of the following damages cells and causes cell aging?
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inflammation
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The researchers used strands of DNA located at the ends of chromosomes (called telomeres) to classify the cells they studied. What assumption did they make about telomeres?
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Longer telomeres indicate younger cells.
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The researchers found that telomeres were ______.
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longer in individuals who exercised regularly
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The research showed that individuals who _______ had younger looking cells based on telomere measurements.
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exercised for an average of 30 minutes per day
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Which of the following is true?
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Overall, the nuclear accident at Fukushima was not as bad as the accident at Chernobyl.
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You were exposed to 4 millisieverts of radiation last year. That is ______ times the maximum recommended by the International Commission on Radiological Protection.
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4
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Members of what organization collected samples that have indicated high radiation levels in Tokyo?
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Radiation Defense Project
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What radioactive element is being tested for in this ongoing project?
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Cesium
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What caused the nuclear accident at Fukushima?
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a tsunami
