Term
| One Gene-One Polypeptide Hypothesis |
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Definition
| The premise that a gene is a segment of DNA that codes for one polypeptide. |
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Definition
| The synthesis of RNA on a DNA template. |
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| A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein. |
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| The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of languagefrom nucleotides to amino acids. |
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Definition
| A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits. |
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Definition
| Modification of RNA before it leaves the nucleus, a process unique to eukaryotes. |
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Definition
| An initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene. |
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Term
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Definition
| A set of three-nucleotide-long words that specify the amino acids for polypeptide chains. |
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Definition
| The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript. |
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Definition
| A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code. |
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Definition
| The way a cell’s mRNA-translating machinery groups the mRNA nucleotides into codons. |
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Definition
| An enzyme that links together the growing chain of ribonucleotides during transcription. |
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Definition
| A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA. |
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Definition
| In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene. |
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Definition
| A region of a DNA molecule that is transcribed into an RNA molecule. |
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Definition
| A regulatory protein that binds to DNA and stimulates transcription of specific genes. |
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Term
| Transcription Initiation Complex |
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Definition
| The completed assembly of transcription factors and RNA polymerase bound to the promoter. |
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Definition
| A promoter DNA sequence crucial in forming the transcription initiation complex. |
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Definition
| When the 5' end of mRNA is capped off with a modified form of guanine. |
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Definition
| The modified end of the 3’ end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides. |
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Definition
| The removal of noncoding portions (introns) of the RNA molecule after initial synthesis. |
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Definition
| A noncoding, intervening sequence within a eukaryotic gene. |
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Definition
| A coding region of a eukaryotic gene. Exons, which are expressed, are separated from each other by introns. |
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Term
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Definition
| A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. |
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Definition
| A type of regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns. |
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Definition
| An independently folding part of a protein. |
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Definition
| An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA. |
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Definition
| A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule. |
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Term
| Aminoacyl-tRNA Synthetase |
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Definition
| An enzyme that joins each amino acid to the correct tRNA. |
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Term
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Definition
| A violation of the base-pairing rules in that the third nucleotide (5’ end) of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3’ end) of a codon. |
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Definition
| The most abundant type of RNA, which together with proteins forms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons. |
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Term
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Definition
| One of a ribosome’s three binding sites for tRNA during translation. Holds the tRNA carrying the growing polypeptide chain. |
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Definition
| One of a ribosome’s three binding sites for tRNA during translation. Holds the tRNA carrying the next amino acid to be added to the polypeptide chain. |
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Definition
| One of a ribosome's three binding sites for tRNA during translation. Discharges the the tRNA. |
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Term
| Polyribosomes (Polysomes) |
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Definition
| An aggregation of several ribosomes attached to one messenger RNA molecule. |
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Definition
| A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell. |
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Term
| Signal-Recognition Particle (SRP) |
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Definition
| A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome. |
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Definition
| A change in the DNA of a gene, ultimately creating genetic diversity. |
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Definition
| A change in a gene at a single nucleotide pair. |
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Definition
| A type of point mutation; the replacement of one nucleotide and its partner in the complementary DNA strand by another pair of nucleotides. |
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Definition
| The most common type of mutation, a base-pair substitution in which the new codon makes sense in that it still codes for an amino acid. |
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Definition
| A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein. |
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Definition
| A mutation involving the addition of one or more nucleotide pairs to a gene. |
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Definition
| A mutational loss of one or more nucleotide pairs from a gene. |
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Definition
| A mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons. |
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Term
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Definition
| A chemical or physical agent that interacts with DNA and causes a mutation. |
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