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Genetics Exam 2
| Term | Definition |
|---|---|
| Basal transcription apparatus | General transcription factors (accessory proteins), along with RNA polymerase creates core protein |
| RNA Polymerase II | Polymerase that completes mRNA synthesis |
| TATA box | core promoter box TATAAAA upstream of start site, 20-30 base pairs, bound by transcription factors |
| Regulatory promoter | the binding site for the basal transcriptional apparatus; upstream of transcription start site recognized by transcription activator; variety of different consensus sequences |
| General transcription factors | form basal apparatus along with RNA polymerase II |
| transcriptional activator proteins | bind to regulatory promoter and enhancer sequences; high levels of transcription; stimulate the assembly of the basal apparatus at the start site |
| TFIID | general transcription factor responsible for interacting with the TATA-binding protein and recruiting RNA polymerase II into the initiation complex |
| enhancers | short regulatory elements of accessible DNA that increase the transcription of target genes |
| mediator | complex of proteins that mediates the interaction between activator protein, RNA polymerase II, and general transcription factors |
| RNA Polymerase I | termination factor (like Rho) that binds to DNA sequence downstream of transcription site |
| RNA Polymerase III | transcribes a terminator sequence >> string of uracil nucleotides in the RNA molecule (similar to rho-independent termination) |
| Rat 1 | enzyme with 5' to 3' exonuclease activity that degrades synthesizing RNA until it reaches RNA Polymerase II in order to stop transcription |
| elongation | transcription start site gets unwound, RNA Polymerase leaves promoter and dissociates from many transcription factors; moves downstream with a transcription bubble containing roughly 8 nucleotides of DNA-RNA hybrid |
| pre-mRNA | must be processed in order to become functional mRNA |
| collinearity theory | the number of nucleotides in the gene is proportional to the number of amino acids in the protein (3 nucleotides per codon) |
| introns | non-coding intervening sequence |
| exons | coding regions |
| 8-9 | how many introns does the average human genome contain? |
| not translated | sequences at the beginning and end of RNA, including the promoter, RNA coding sequence, and terminator are |
| mature mRNA | contains 3 primary regions: 5' untranslated region (UTR, leader sequence), protein-coding region, and 3' untranslated region (trailer) |
| Shine-Dalgarno | sequence that is a ribosomal binding site in bacterial and archaeal messenger RNA |
| 5' cap | facilitates binding of ribosome to 5’ end of mRNA, increases mRNA stability; functions in initiation |
| poly(A) tail | increases stability of mRNA, facilitates binding of ribosome to mRNA; slows down degradation |
| RNA splicing | removes non-coding introns from pre-mRNA, facilitates export of mRNA to cytoplasm, allows for multiple proteins to be produced through alternative splicing |
| RNA editing | alters nucleotide sequence of mRNA |
| spliceosome | one of the largest molecular complex structures, catalyzes splicing; consists of 5 snRNAs |
| U2 | snRNP that binds to branch point |
| alternative processing | the process of selecting different combinations of splice sites within pre-mRNA to produce variably spliced mRNAs. |
| one gene, one enzyme hypothesis | Beadle and Tatum: Genes function by encoding enzymes, and each gene encodes a separate enzyme |
| structural | protein function: Provide structure, shape, support for membrane, bone, hair, etc |
| enzymatic | protein function: Drive metabolic reactions for metabolites synthesis and break down |
| receptor | protein function: Response to environmental signals |
| regulatory | protein function: Transcription factors, activators |
| alanine | ala |
| arginine | arg |
| asparagine | asn |
| aspartic acid | asp |
| cysteine | cys |
| glutamic acid | glu |
| glutamine | gln |
| glycine | gly |
| histidine | his |
| isoleucine | ile |
| leucine | leu |
| lysine | lys |
| methionine | met |
| phenylalanine | phe |
| proline | pro |
| serine | ser |
| threonine | thr |
| tryptophan | trp |
| tyrosine | tyr |
| valine | val |
| nonpolar aliphatic | R group containing glycine, alanine, valine, leucine, isoleucine, methionine |
| polar uncharged | R group containing serine, threonine, cysteine, proline, asparagine, glutamine |
| aromatic | R group containing phenylalanine, tyrosine, tryptophan |
| positively charged | R group containing lysine, arginine, histidine |
| negatively charged | R group containing aspartate and glutamate |
| translation | The synthesis of a polypeptide based on the sequence of an mRNA molecule |
| aminoacyl-tRNA synthetases | enzymes that catalyze the bonding of tRNA to an amino acid; provides critical link between nucleic acids to proteins |
| AUG | start codon; methionine |
| UAA, UAG, UGA | stop codons |
| codon | 3 consecutive nucleotides in mRNA |
| degeneracy of the code | there are 61 codons for 20 amino acids; some codons code for the same amino acid |
| isoaccepting tRNAs | different tRNAs that accept the same amino acid but have different anticodons |
| wobble rules | anticodon can bond with different bases in the 3rd position of the codon |
| synonymous codons | codons that specify the same amino acid |
| modified bases | chemical changes made to standard bases after transcription by tRNA modifying enzymes |
| CCA | sequence at the end of all tRNAs |
| COO- | 3' end of adenine attaches to ______ of an amino acid to carry it |
| 50S | large ribosome subunit |
| 30S | small ribosome subunit |
| f-Met | charges tRNA so it can form a complex with IF2 and GTP |
| peptidyl site | P site; first site, bound to f-Met; receives primary amino acid |
| aminoacyl site | A site; second site; receives second amino acid |
| RF3 | binds to ribosome to release RF1 or RF2 and tRNA from the P site to the E site |
| RF1/RF2 | binds to A site to release the polypeptide chain from the P site |
| regulatory genes | genes whose products, either RNA or protein, interact with DNA sequences of other structural genes and affect their expression |
| structural genes | encodes proteins that are used in metabolism or biosynthesis or that play a structural role in the cell |
| regulatory elements | DNA sequences that are not transcribed but play a role in regulating other nucleotide sequences |
| constitutive expression | continuously expressed under normal cellular conditions; structural genes |
| motif | within the binding domain, a simple structure that fits into the major groove of the DNA: helix-turn-helix, zinc fingers, leucine zipper |
| operon | a group of bacterial structural genes that are transcribed together plus the controlling sequences; regulates gene expression at transcriptional level; bound by promoter and structural genes |
| negative control | the regulator protein is a repressor |
| positive control | the regulator protein is an activator |
| inducible operon | transcription is normally off |
| repressible operon | transcription is normally on |
| inducer | small molecule that binds to turn on transcription |
| co-repressor | small molecule that binds to turn off transcription |
| Lac Operon negative control | When lactose or allolactose is present in the medium where the bacteria grows, 3 genes are expressed to metabolize lactose |
| Lac Operon positive control | lacZ gene codes for b-galactosidase which cleaves lactose into galactose and glucose for bacteria to utilize; high glucose = no transcription; low glucose = transcription |
| trp operon | when tryptophan is present, it binds to repressor, allowing transcription |
Created by:
ejvanriper
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