| Term | Definition |
|---|
| 5' cap | The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide. |
| A site | One of a ribosome's three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA.) |
| Alternative RNA Splicing | 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. |
| aminoacyl-tRNA synthetase | An enzyme that joins each amino acid to the correct tRNA |
| anticodon | A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule. |
| base-pair substitution | A type of point mutation; the replacement of one nucleotide and its partner in the complementary DNA strand by another pair of nucleotides. |
| codon | A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code. |
| deletion | 1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene. |
| domain | 1) A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya. (2) An independently folding part of a protein. |
| E site | One of a ribosome's three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome. (E stands for exit.) |
| exon | A coding region of a eukaryotic gene. Exons, which are expressed, are separated from each other by introns |
| frameshift mutation | 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. |
| insertion | A mutation involving the addition of one or more nucleotide pairs to a gene. |
| intron | A noncoding, intervening sequence within a eukaryotic gene. |
| messenger RNA (mRNA) | A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein. |
| missense mutation | 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. |
| mutagen | A chemical or physical agent that interacts with DNA and causes a mutation. |
| mutation | A rare change in the DNA of a gene, ultimately creating genetic diversity. |
| nonsense mutation | A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein |
| one gene–one polypeptide hypothesis | The premise that a gene is a segment of DNA that codes for one polypeptide. |
| P site | One of a ribosome's three binding sites for tRNA during translation. The P site holds the tRNA carrying the growing polypeptide chain. (P stands for peptidyl tRNA |
| point mutation | A change in a gene at a single nucleotide pair |
| poly-A tail | The modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides. |
| polyribosome (polysome) | An aggregation of several ribosomes attached to one messenger RNA molecule |
| primary transcript | An initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene |
| promoter | A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA |
| reading frame | The way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons. |
| ribosomal RNA (rRNA) | 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 |
| ribosome | 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. |
| ribozyme | An enzymatic RNA molecule that catalyzes reactions during RNA splicing. |
| RNA polymerase | An enzyme that links together the growing chain of ribonucleotides during transcription. |
| RNA processing | Modification of RNA before it leaves the nucleus, a process unique to eukaryotes. |
| RNA splicing | The removal of noncoding portions (introns) of the RNA molecule after initial synthesis. |
| signal peptide | A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell. |
| signal-recognition particle (SRP) | A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome. |
| spliceosome | A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. |
| TATA box | A promoter DNA sequence crucial in forming the transcription initiation complex. |
| template strand | The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript. |
| terminator | 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. |
| transcription | The synthesis of RNA on a DNA template. |
| transcription factor | A regulatory protein that binds to DNA and stimulates transcription of specific genes. |
| transcription initiation complex | The completed assembly of transcription factors and RNA polymerase bound to the promoter. |
| transcription unit | A region of a DNA molecule that is transcribed into an RNA molecule. |
| transfer RNA (tRNA) | 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. |
| translation | The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of languagefrom nucleotides to amino acids |
| triplet code | A set of three-nucleotide-long words that specify the amino acids for polypeptide chains. |
| wobble | 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. |
| anti- | opposite ex: anticodon |
| exo- | out, outside, without ex: exon |
| intro- | within ex: intron |
| muta- | change ex: Mutagen |
| -gen | producing ex: Mutagen |
| poly- | many ex: polyA tail |
| trans- | across ex:transcription |
| -script | write ex: transcription |
Combine with other sets
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