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30 Cards in this Set
- Front
- Back
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central dogma
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the concept that cells are governed by a cellular chain of command: DNA->RNA->protein
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transcription
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the synthesis of RNA under the direction of DNA. transcription produces mRNA, prokaryotes produce is immediately translated without more processing, eukaryotes modify RNA through processing
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translation
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the synthesis of polypeptide, which occurs under the direction of mRNA. happens in the ribosomes
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triplet code
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a series of nonoverlapping, three-nucleotide words known as a codon, smallest units of uniform length that can code for all the amino acids
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codons
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during translation the mRNA base triplets are read in the 5' to 3' direction
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stop codons
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UAA, UGA, UAG
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AUG
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start codon
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RNA polymerase
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RNA synthesis is catalyzed by this, which pries the DNA strands apart and hooks together the RNA nulcleotides
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promoter
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the DNA sequence where RNA polymerase attaches is called; in bacteria the sequence signaling the end of transcription is called the terminator
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transcription unit
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the stretch of DNA that is transcribed is called
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initiation, elongation, termination
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transcription occurs in three stages
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TATA box
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crucial in forming the initiation complex in eukaryotes
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transcription factors
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mediate the binding of RNA polymerase II and the initiation of transcription
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transcription initiation complex
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the completed assembly of transcription factors and RNA polymerase II bound to a promoter is called
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introns
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noncoding regions are called intervening sequences or
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exons
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the other regions that are expressed, are usually translated into amino acid sequences
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RNA splicing
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removes introns and joins exons, creating an m RNA molecule with a continuous coding sequence
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transfer RNA
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a cell translates an mRNA message into protein with the help of this
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ribosomes
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facilitate specific coupling of tRNA anticodons with mRNA codons in protein synthesis
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initiation
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the stage of translation brings together mRNA, a tRNA with the first amino acid, and the two ribosomal subunits. start codon AUG
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elongation
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during this stage, amino acids are added one by one to the preceding amino acids
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termination
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occurs when a stop codon UAA, UGA, UGA
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mutations
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changes in the genetic material of a cell or virus
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point mutation
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chemical changes in just one base pair of a gene and can occur during DNA replication, recombination, or reapir
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base pair substitution
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replaces one nucleotide and its partner with another pair of nucleotides
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silent mutation
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have no effect on the amino acid produced by a codon because of redundancy in the genetic code
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missense mutations
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still code for an amino acid but not necessarily the right amino acid
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nonsense mutations
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change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein
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insertion deletion
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additions of losses of nucleotide pairs in a gene
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frameshift mutation
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altering of the reading frame
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