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68 Cards in this Set
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gene expression
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DNA directs synthesis of proteins indrectly.
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1909 - Archibald Garrod
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Proposed that genes dictated phenotypic expressions through enzymes that catalyze specific chemical reactions.
Disease = inability to make enzyme. |
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George Beadle and Borris Ephrussi (1930's)
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tested in Drosphilia and mold to find that, when DNA was damaged, a certain protein could not be produced depending on what stage was halted by X rays.
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One gene-one polypeptide
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the law made by Beadle and Ephrussi that states that each gene codes for a polypeptide (because genes make both enzymes and proteins, and sometimes more than one polypeptide makes a protein.
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Transcription
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synthesis of mRNA that carries genetic message to protein-synthesizing machine.
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Translation
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the process of synthesizing polypeptide chains under the direction of mRNA and ribosomes.
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Triplet Code/codon
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3 nucleotide bases code for 1 amino acid on the mRNA.
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template strand
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one of the 2 DNA strands that is used for transcription and is read from 3' to 5'.
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Marshall Nirenberg (1961)
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first deciphered a codon.
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AUG
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start codon, coding for the amino acid Methanine.
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RNA polymerase II
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takes apart DNA strands and hooks RNA on, assembling RNA in 5' to 3' direction. no primer needed.
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Promoter
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DNA sequence where RNA polymerase attaches and initiates.
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TATA box
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where the transcription factors bind so the RNA polymerase can bind to them.
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Transcription Factors
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proteins that help RNA polymerase bind to the promoter.
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Terminator
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sequence signaling the end of transcription.
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Transcription Unit
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The complex in which the RNA is transcribed (strech of DNA)
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Transcription-Initation complex
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RNA polymerase with Transcription factors and promoter.
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Elongation
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when RNA nucleotides are added to the 3' end, exposing only 10-20 DNA bases at a time.
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Polyadenylation Signal Sequence
(AAUAAA) |
the sequence that signals the pre-mRNA to leave the complex and continue to processing. the RNA polymerase doesn't detach until further downstream.
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5' cap
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at the 5' end of mRNA to protect it, there is a G3P or Guanine 3 Phosphate attached.
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Poly A Tail
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50-250 Adenines that are added at the 3' end of mRNA to protect it.
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UTR
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untranslated regions that help with binding but not with translation in RNA.
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RNA splicing
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when the Introns (noncoding sequences) are taken out and the Exons (coding sequences) spliced together.
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Small Nuclear Ribonuclearproteins
(snRNP's - "snurps") |
RNA and Proteins that help in splicing RNA.
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Spliceosome
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joins with "Snurps" and splices RNA.
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tRNA
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RNA on an amino acid with anticodon
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anticodon
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matches to codon and is found on the tRNA
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amino acid attachment site
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3' end of mRNA
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aminoacyl tRNA synthetase
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enzyme that creates aminoacyl tRNA (active tRNA (tRNA with amino acid))
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wobble
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relaxed base pairing rule, mostly relevant to the third base.
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A site (aminoacyl tRNA binding site)
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first binding place on ribosome where the tRNA can bind.
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P site (peptidyl tRNA binding site)
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second ribosome binding site where the tRNA deposits its amino acid.
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E (Exit) site
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site on the ribosome where the tRNA without the amino acid is ejected.
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Ribosomal RNA (rRNA)
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RNA that makes up ribosomes; made in nucleolus.
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exit tunnel
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where the popypeptides exit the ribosome.
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initiator tRNA
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contains the start codon AUG with the amino acid Methionine
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initiation factors
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bring together components for translation.
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reading frame
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established by first codon and keeps reading 3 codons at a time.
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GTP
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energy to form complex for translation
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Elongation factors
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proteins that help with the process of translation. hydrolyze G3P
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codon recognition
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anticodon pairs with RNA at A site and use 2GTP for energy.
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peptide bond formation
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when the new amino acid covalently bonds with the amino acid chain. GTP used.
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translocation
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when the used up or "empty" tRNA in the P site is moved to the E site and ejected and the tRNA in the A site is moved to the P site.
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stop codon
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UAG, UAA, or UGA
enters A site to end translation |
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polyribosomes
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strings of ribosomes working on the same mRNA
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chaperomin
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helps the protein fold correctly after translation
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polysomes
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polyribosomes
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signal recognition particle (SPR)
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binds fto signal peptide and stops synthesis for a moment in the cytosol, allowing it to bind to receptor protein in ER membrane.
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translocation complex
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the protein, ribosome, ER complex where the protein is synthesized into the ER.
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mRNA (messanger RNA)
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carries information specifying amino acid sequences for proteins from DNA.
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tRNA (transfer RNA)
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adaptor molecule in protein synthesis that translates mRNA into amino acids.
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Primary transcript (pre-mRNA)
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precursor to mRNA, rRNA and tRNA. intron RNA acts as ribosome to catalyze its own splicing.
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SPR RNA
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signal recognition particle RNA. protein RNA complex recognizing signal peptides of polypeptides targetted to ER>
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small nuclear RNA (snRNA)
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makes splicosomes with proteins that splice introns in pre-mRNA.
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small nucleolar RNA (snoRNA)
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processing pre-rRNA in the nucleolus.
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small interfering RNA (siRNA) or micro RNA (miRNA)
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regulation of gene expression.
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mutations
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changes in genetic material of a cell.
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point mutations
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chemical changes in one base pair of a DNA sequence.
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substitution mutations
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when a single base is substituted for another base.
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silent mutations
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mutations with no effect
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missense mutations
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altered codon codes for amino acid that makes sense but not right sense or amino acid.
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nonesense mutations
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mutated codon codes for stop mutation and translation is terminated prematurely.
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insertion mutation
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addition of nucleotide pair or codon.
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deletion mutation
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deletion of a nucleotide pair or codon.
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frame shift mutation
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when the reading frame is shifted and all codons downstream are misread.
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mutagens
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causes DNA mutations
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spontanious mutations
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errors in DNA
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gene
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region of DNA whose final product is either a polypeptide or an RNA molecule.
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