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Prof Mirabito
Exam 3 definitions
| Question | Answer |
|---|---|
| 3'polyadenylation5' | During eukaroytic pre-mRNA processing, an enzyme -driven modification that removes the 3'end of the pre-mRNA and adds numerous adenines |
| 3' splice site | In eukaryotic pre-mRNA processing, the location of cleavage at the 3'end of an intron. Contains an AG dinucleotide in a consensus sequence. |
| 5' splice site | In mRNA processing, the location of cleavage at the 5' end of an intron. Contains a GU dinucleotide in a consensus sequence. |
| 5' capping | In pre-mRNA processing the addition of 7-methylguanosine to the nucleotide at the end of pre-mRNA by a triphosphate bridge. Methylation of adjacent nucleotides may also occur. |
| -35 consensus sequence | A specific consensus sequence of the bacterial promoter at the polymearase is bound. |
| coding strand | nontemplate strand of DNA thart has the same 5'-to3' polarity as its transcript and the same sequence, except for T in DNA and U in RNA. |
| consensus sequence | nucleotide sequence in a dna segment derived by comparing sequences of similar segments from other genes or organisms. |
| downstream | reffering to a gene or sequence location that is toward the 3' direction on the coding strand. |
| enhancer sequence | set of regulatory sequences that bind specific transcriptional proteins that can elevate transcription of targeted eukaryotic genes. |
| silencer sequence | regulatory dna sequences that can repress transcription ofspecific genes that may be located distantly from the sequence. |
| stem-loop (hairpin structure) | short double stranded segments of rna topped by a single stranded loop containing unpaired nucleotides |
| intrinsic termination | Inverted repeat dna sequences induce formation of 3' mrna stem loop structures that are followed by multiple uracils |
| intron splicing | spliceosome complex driven process that removes introns from eukaryotic pre mrna and ligates exons to form mature mrna |
| messenger RNA (mRNA) | form of rna yranscribed from a geneand subsequently translated to produce a polypeptide or protien |
| nontemplate strand | nontemplate strand of DNA thart has the same 5'-to3' polarity as its transcript and the same sequence, except for T in DNA and U in RNA. |
| template strand | dna strand serving as a template for synthesis of a complementary nucleic acid strand. |
| termination sequence | dna seqences that serve to stop transcription. |
| transcription factors (TFs) | protiens that bind promoters and are functional in transcription |
| polyadenylation signal sequence | hexanucleotide seqence of mrna. usually AAUAAA, that identifies the location of 3'pre mrna cleavage and polyadenylation |
| precursor mRNA (pre-mRNA) | initial transcript of eukaryotic gene reguiring mrna processing prior to translation |
| promoter | regulatory seqence of dna near 5' end of a gene that acts as binding location of rna polymerase and directs rna polymearase to the start of transcription |
| sigma subunit (alternative sigma subunits) | Accesory protein that changes the promoter recognition specificity of the bacterial rna polymearase core enzyme. |
| upstream | referring to a gene or seqence in location that is toward the 5' direction of the coding strand. |
| 3' untranslated region (3'UTR) | untranslated segment of mrna between the stop codon and the 3' end of the transcript. |
| 5' untranslated region (5'UTR) | untranslated segment of mrna between the 5' end of the transcript and the start codon. |
| charged tRNA | trna to which the correct amino acid has been attached. |
| Kozak sequence | specific consensus of eukaryotic mrna that conatins the authentic start codn sequence. |
| polycistronic mRNA | mrna containing the transcriptsof two or more genes |
| Shine-Dalgarno sequence | 5' UTR mrna consensus seqence that pair with nucleotides near the 3' end of 16s rrna in the small ribosomal subunit to orient the start codon on ribosome |
| uncharged tRNA | trna not carrying an amino acid. |
| activator binding site | dna seqence to which an activator protein binds to regulate gene expression. refers to the regulatory site. |
| activator protein | transcriptionfactor that binds to regulatory sequences associated with a gene and upregulates that genes expression |
| allolactose | modified form of lactose that binds to the lac repressor protein, that reduces the dna binding ability of the complex. |
| allosteric domain (allostery) | domain of a protein to change shape when it binds to a specific molecule; the protein in the new shape is altered in its ablility to bind to a second molecule. |
| allosteric effector compound | molecule that binds to the allosteric protein domain and subseqently induces a change in bound protein. |
| attenuation (attenuator region) | regulatory region downstreamof the promoter of repressible amino acid operons that exert transcriptional control based on the translationof leader peptide; the efficency of which is determined by the availabililty of specific amino acids |
| CAP binding site (CAP-cAMP complex) | formed by joining catabolite proteins to camp, that complex binds to the camp binding site of the bacterial lac promoter to regulate gene expression. |
| catabolite repression | situationwhere the presence of the catabolite represses the transcription of genes for analtrnative catabolite. |
| cis-acting | Acting on the same chromosome |
| cis-dominant | principle that he operator can infuence only transcription of adjacent downstream genes |
| constitutive transcription (constitutive mutants) | State in which a gene is continuosly transcribed |
| corepressor | accesorymolecule required for a repressor protein to exert its function. |
| DNA-binding domain | |
| inducer | accesory molecule that binds to a protein that leads to activation of gene expression. the inducer can bind to a repressor protein and prevent its function or bind to an activator protein and stimulate its function |
| inducer-repressor complex | molecular complex consisting of a repressor protein protein and a bound inducer molecule. |
| inducible operon | operon that is not expressed under one set of enviromental conditions, but whose transcription is activated under alternative enviromental conditions |
| induction | process by which one cell or tissue promotes a particular developmental fate in neigboring cells or tissues. |
| inhibitor | accesory molecule thta converts activator proteins to an inactive conformation by binding to an allosteric binding domain of the activator protein |
| lac+ phenotype | Bacteria that are able to grow on a medium containg lactose as the only sugar |
| lac- phenotype | bacteia that are not able to grow on a medium conating lactose as the only sugar. |
| lacA gene (lacY gene, lacZ gene) | |
| leader region (trpL) | |
| negative control (of transcription) | |
| noninducible | |
| operator | |
| operon | |
| polycistronic mRNA | |
| positive control | |
| regulated transcription | |
| repressible operon | |
| repressor protein | |
| stem loop [3-4 (termination), 2-3(antitermination)] | |
| trans-acting | |
| translation repressor protein | |
| chromatin modifier | |
| chromatin remodeling | |
| cis-acting regulatory sequence | |
| closed chromatin | |
| covered promoter | |
| CpG dinucleotide (CpG island) | |
| DNase I hypersensitive site | |
| enhancer (enhancer sequence) | |
| epigenetic modification | |
| geonomic imprinting | |
| imprinting control region (ICR) | |
| insulator sequence | |
| operon chromatin | |
| open promoter | |
| silencer sequence | |
| trans-acting regulatory protein | |
| upstream activator sequence (UAS) |