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96 Cards in this Set
- Front
- Back
________ is the study of heredity.
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Genetics
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The genetic information in a cell is called the ___________.
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genome
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A cell's genome is organized into ______________.
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chromosomes
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A cell's genetic information is organized into ________________.
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chromosomes
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A cell's ________ is organized into chromosomes.
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genome
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________ are structures containing DNA that physically carry hereditary information.
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Chromosomes
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_________ carry genes.
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Chromosomes
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Chromosomes carry ________.
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genes
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Fill in the blanks with these two words in the proper order: chromosomes, genes.
________ carry _________. |
chromosomes carry genes
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_______ are segments of DNA
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Genes
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_______ are segments of DNA that code for functional proteins.
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Genes
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_________ are repeating units that compose the macromolecule of DNA.
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nucleotides
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What are nucleotides?
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repeating units that compose DNA
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What is the structure of a nucleotide?
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Each nucleotide consists of :
- a nitrogenous base (adenine, thymine, cytosine or guanine) - deoxyribose ( a pentose sugar) - phosphate group |
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The ________ is an organism's genetic makeup, the information that codes for all the particular characteristics of the organism.
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genotype
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The _________ refers to the actual, expressed properties of an organism
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phenotype
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Fill in the blanks with these two words in the correct order: genotype, phenotype.
_________ is the manifestation of __________. |
phenotype is the manifestation of genotype.
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An organism's ________ is its collection of genes.
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genotype
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An organism's ________ is its entire DNA
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genotype
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An organism's _______ is its collection of proteins.
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phenotype
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The DNA within a cell exists as long strands of _______ tiwsted together in pairs to form a double-helix.
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nucleotides
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The DNA within a cell exists as long strands of nucleotides twisted together in pairs to form a ________.
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double-helix
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Each strand of DNA is made up of what?
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string of alternating sugar and phosphate groups, with a nitrogenous base attached to each sugar in the backbone.
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What is the sugar phosphate backbone?
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a string of alternating sugar and phosphate groups, with a nitrogenous base attached to each sugar of the backbone.
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Adenine always pairs with _________.
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thymine
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Thymine always pairs with ________.
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adenine
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Guanine always pairs with _________.
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cytosine
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Cytosine always pairs with ________.
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guanine
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What are the purines?
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adenine and guanine
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What are the pyrimidines?
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cytosine and thymine
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The base pairings of nucleotides are ________.
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complementary
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The two strands of DNA are _________.
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complementary
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DNA is synthesized in the _______ direction.
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5'-------->3'
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RNA synthesis continues until RNA polymerase reaches a site on the DNA called the _________.
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terminator
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What is the terminator?
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a site on the DNA that "signals" RNA polymerase to stop synthesizing RNA
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______ are the regions of DNA that are expressed
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exons
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_______ are the regions of DNA that do not encode protein.
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introns
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What are constitutive genes?
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their products are not regulated; their products are constantly produced at a fixed rate. Usually these genes are effectively turned on all the time, so they code for enzymes that the cell needs in fairly large amounts.
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What is repression?
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the regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes
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What term is best described by the following:
" The regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes is called _______. " |
repression
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Repression is mediated by regulatory proteins called ________.
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repressors
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What do repressors do?
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they block the ability of RNA polymerase to initiate transcription from the repressed genes
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What is the process that turns on the transcription of a gene/genes?
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induction
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What is induction?
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the process that turns on the transcription of a gene/genes
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A substance that acts to induce transcription of a gene is called an ________
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inducer
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what is an inducer?
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a substance that acts to induce transcription of a gene
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Enzymes synthesized in the presence of induces are ___________.
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inducible enzymes
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the combination of an operator, promeoter, and the structural genes they control is known as _______
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an operon
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What is an operon?
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the combination of an operator, promotor, and the structural genes they control.
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How are inducible operons and repressible operons different?
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In inducible operons, the structural genes are transcribed when they are turned on, or induced. In repressible operons, the structural genes are transcribed UNTIL they are turned off, or repressed.
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An example of an inducible operon is the _______ operon.
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lac
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An example of a repressible operon is the _________ operon.
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tryptophan
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Inhibition of the metabolism of alternative carbon sources by glucose is termed ___________.
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catobolite repression
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catobolite repression is also known as the ___________.
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glucose effect
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__________ is also known as the glucose effect.
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catobolite repression
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How does catabolite repression work?
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keeps making C-amp until turned off by realizing that the body has enough glucose.
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What is a bse mutation?
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a single base at one point in the DNA sequence is replaced with a different base.
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What is a missense mutation?
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If a base situation results in an amino acid substitution in the synthesized protein, it is referred to as a missense mutation
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What term is best described:
" a base situation results in an amino acid substitution in the synthesized protein " |
missense mutation
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What term is best described:
" a base substitution resulting in a stop (nonsense) codon " |
nonsense mutation
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What is a nonsense mutation?
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When a base substitution results in a stop (nonsense) codon, preventing the synthesis of a completely functional protein.
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What is a frameshift mutation?
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When one or a few of the nucleotide pairs are deleted or inserted in the DNA
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What term is best described:
" When one or a few of the nucleotide pairs are deleted or inserted in the DNA" |
frameshift mutation
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Spontaneous mutations are what?
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when mistakes occur during DNA replication in the absence of an apparent mutation-causing agents.
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What term is best described:
" when mistakes occur during DNA replication in the absence of an apparent mutation-causing agent " |
spontaneous mutation
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What are mutagens?
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agents in the environment, such as certain chemicals and radiation, that directly or indirectly bring about mutation
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What term is best described:
" agents in the environment, such as certain chemicals and radiation, that directly or indirectly bring about mutation " |
mutagens
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How do chemical mutagens work?
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convert the base adenine (A) to form in such a way that it no longer pairs with thymine (T), but with cytosine (C).
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How do ionizing radiation cause mutations?
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causes the formation of ions and free radicals that react with DNA and can break the sugar-phosphate backbone or cause base substitutions
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UV radiation causes mutations how?
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by causing bonding between adjacent thymines
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How are thymine dimers repaired?
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thymine dimers can be repaired by light-repair enzymes
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What do light-repair enzymes do?
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repair thymine dimers
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________ involves detection of mutant cells by rejection of the unmutated parent cells
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positive (direct) selection
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In lameman's terms, what does this mean:
" involves detection of mutant cells by rejection of the unmutated parent cells " |
you want the mutants!
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What term is best described:
" this process selects a cell that connot perform a certain function " |
negative (indirect) selection
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Positive selection is ________.
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direct
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Negative selection is _______.
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indirect
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Another term for direct selection is __________.
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positive selection
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another term for indirect selection is ____________.
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negative selection
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What is replica plating technique used for?
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negative selection
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_________ is a relatively inexpensive and rapid test for identifying possible chemical carcinogens.
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Ames test
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What does the Ames test identify?
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posisble chemical carcinogens
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What does the Ames test assume?
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that a mutant cell can revert to a normal cell in the presence of a mutagen, and that many mutagens are carcinogenic
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In prokaryotes, transcription occurs in the _________
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cytoplasm
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In eukaryotes, transcription occurs in the ________
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nucleus
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" ATGCTATTG " is an example of a code for DNA or RNA? How can you tell?
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DNA: presence of thymines
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" AUGCUAUUG " is an example of a code for DNA or RNA? How can you tell?
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RNA: presence of uracil
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In DNA, adenine pairs with __________.
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thymine
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In RNA, adenine pairs with __________.
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uracil
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an MRNA is read in what direction?
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5'------->3'
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There are _____ codons.
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64
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In prokaryotes, __________ can begin before transcription is complete.
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translation
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In _________, translation can begin before transcription is complete
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prokaryotes
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Genes for the enzymes in glycolosis are examples of what type of enzymes?
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constitutive enzymes
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The start codon codes for the amino acid _________.
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methionine
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Another word for the stop codon is a ________ codon.
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nonsense
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