Chapter 17
Terms : Hide Images
| 728077936 | Gene expression | The process by which DNA directs the synthesis of proteins (or in some cases, just RNAs). | |
| 728077937 | Transcription | Process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA | |
| 728077938 | Messenger RNA | Carries a genetic message from the DNA to the protein-synthesizing machinery of the cell. | |
| 728077939 | Translation | Synthesis of a polypeptide using the information in the mRNA. | |
| 728077940 | Ribosomes | Complex particles that facilitate the orderly linking of amino acids into polypeptide chains | |
| 728077941 | Primary transcription | An initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene. | |
| 728077942 | Directional flow of genetic information | DNA, -> RNA, -> Protein. | |
| 728077943 | Triplet Code | The genetic instructions for a polypeptide chain are written in the DNA as a series of nonoverlapping, three-nucleotide words. | |
| 728077944 | Template strand | The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript. | |
| 728077945 | Codons | A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code. | |
| 728077946 | Reading frame | The way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons. | |
| 728077947 | RNA polymerase | An enzyme that links together the growing chain of ribonucleotides during transcription. | |
| 728077948 | Promoter | A specific nucleotide sequence in DNA that binds RNA polymerase and indicated where to start transcribing RNA. | |
| 728077949 | Terminator | A specific nucleotide sequence in DNA that signals the end of transcription. | |
| 728077950 | Transcription unit | A region of a DNA molecules that is transcribed into an RNA molecule. | |
| 728077951 | Transcription factor | A regulatory protein that binds to DNA and stimulates transcription of specific genes. | |
| 728077952 | Transcription initiation complex | The completed assembly of transcription factors and RNA polymerase bound to the promoter. | |
| 728077953 | TATA box | A promoter DNA sequence crucial in forming the transcription initiation complex. | |
| 728077954 | RNA processing | Modification of RNA before it leaves the nucleus, as process unique to eukaryotes. | |
| 728077955 | 5 prime Cap | The 5 prime end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide. | |
| 728077956 | Poly-A tail | The modified end of the 3 prime end of an mRNA molecule consisting of the addition of some 50 to 240 adenine nucleotides. | |
| 728077957 | RNA Splicing | The removal of noncoding portions (introns) of the RNA molecule after initial synthesis (similar to editing a video) | |
| 728077958 | Introns | A noncoding, intervening sequence within a eukaryotic gene. | |
| 728077959 | Exons | A coding region of a eukaryotic gene. | |
| 728077960 | Splice-osome | A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. | |
| 728077961 | Ribozymes | Enzymatic RNA molecules that catalyze reactions during RNA splicing. | |
| 728077962 | 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. | |
| 728077963 | Domains | An independently folding part of a protein. | |
| 728077964 | 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. | |
| 728077965 | Anticodon | A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule. | |
| 728077966 | Aminoacyl-tRNA synthetase | An enzyme that joins each amino acid to the correct tRNA. | |
| 728077967 | Wobble | A violation of the base-paring rules in the at the third nucleotide (' end) or a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3' end) of a codon. | |
| 728077968 | Ribosomal RNAs | The most abundant type of RNA, which together with proteins forms the structure of ribosomes. | |
| 728077969 | P site | One of a ribosome's three binding sites for tRNA during translation. It holds the tRNA carrying the growing polypeptide chain. (P stands for peptidyl tRNA). | |
| 728077970 | A site | One of a ribosome's three binding sites for tRNA during translation. It holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA). | |
| 728077971 | E site | One of a ribosome's three binding sites for tRNA during translation. It is the place where discharged tRNAs leave the ribosomes. | |
| 728077972 | Polyribosomes | AKA polysome. An aggregation of several ribosomes attached to one messenger RNA molecule | |
| 728077973 | Signal peptide | A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell. | |
| 728077974 | Signal-recognition particle | SRP. , A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome. | |
| 728077975 | Point mutations | A change in a gene at a single nucleotide pair. | |
| 728077976 | Mutations | A rare change in DNA of a gene, ultimately creating genetic diversity. | |
| 728077977 | Nucleotide-pair substitution | A type of point mutation in which one nucleotide in a DNA strand and its partner in the complementary strand are replaced by another pair of nucleotides. | |
| 728077978 | Silent mutation | A mutation that changes a single nucleotide, but does not change the amino acid created. | |
| 728077979 | 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. | |
| 728077980 | 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. | |
| 728077981 | Insertions | A mutation involving the addition of one or more nucleotide pairs to a gene. | |
| 728077982 | Deletions | A mutational loss of one or more nucleotide pairs from a gene. | |
| 728077983 | 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. | |
| 728077984 | Mutagens | A chemical or physical agent that interacts with DNA and causes a mutation. |
