| Terms |
Definitions |
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pathogenic
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disease-causing
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heterochromatin
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highly compacted chromosomes unavailable for expression
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purines
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adenine and guanine, 2 rings
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Frederick Griffith
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Used pathogenic and nonpathogenic bacteria to discover transformation
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lagging strand
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A discontinuously synthesized DNA strand that elongates in a direction away from the replication fork.
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telomeres
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special nucleotide sequences at the end of DNA, do not contain genes, only prevent staggered ends of the daughter molecule from activating the cell's systems for monitoring DNA damage
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Telomerase
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An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells
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Pyrimidines
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The family of nitrogenous bases that have a single ring.
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primer
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the already existing chain that the nucleotides link onto-short strech of RNA
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DNA Polymerase
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An enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3' end of an existing chain
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Helicases
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enzymes that untwist the double helix at the replication forks
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Okazaki fragments
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segments of the lagging strand synthesized discontinually
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Leading Strand
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The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' -> 3' direction.
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The primer that initiates synthesis of a new DNA strand is usually what type of macromolecule, and which one specifically?
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Nucleotide; RNA
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Primase
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This is an enzyme that joins RNA nucleotides to make the primer. This can start an RNA chain from scratch.
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Erwin Chargaff
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Scientist who stated that DNA had equal amounts of adenine and thymine and equal amounts of cytosine and guanine.
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Topoisomerase
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An enzyme that helps relieve strain by breaking, swiveling, and rejoining DNA strands
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transformation
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A change in genotype and phenotype due to the assimilation of external DNA by a cell.
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protein histones
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positively charged and bind tightly to the negative charged DNA
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Who showed that viral DNA can reprogram cells by putting in new genes?
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Hershey/Chase, 1952
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What is Antiparallel Elongation?
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Antiparallel Elongation occurs because DNA polymerases add nucleotides only to the free 3' end of a growing strand.
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replication fork
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A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are growing.
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Semiconservative Model
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Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand.
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DNA Polymerase 1
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An enzyme that removes the RNA nucleotides of the primer from the 5' end and replaces them with DNA nucleotides
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nuclease
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An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides
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Double Helix
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The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape
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DNA strand can elongate only in the
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5' to 3' direction
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Origin of Replication
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Site where the replication of a DNA molecule begins.
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where DNA polymerases add nucleotides
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DNA polymerases add nucleotides only to the free 3' end of a growing DNA strand.
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What is a helicase?
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A helicase is an enzyme that untwists the double helix at the replication fork.
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What does the semi-conservative model show?
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Each daughter cell is comprised of 1 old strand and 1 new strand.
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