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32 Cards in this Set
- Front
- Back
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aminoacyl tRNA synthetase
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adds an amino acid to tRNA
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peptides/polypeptides
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1. peptides = short chains of aa; polypeptides = logn chains of aa
2. peptide-peptide polymerization makes polypeptides through dehydration rxn 3. polar- amino terminus (left) carboxyl terminus (right) |
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variety of amino acids
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1. determined by R groups
2. R groups give aa different chemical properties |
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levels of protein structure
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1. primary
2. secondary 3. tertiary 4. quartinary |
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secondary protein structure
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1. 3D arrangement of protein structure
2. include: alpha helices and beta sheets (and thirdly, disulfide bridges) 3. held together via Hbonds |
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alpha helices
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helical configurations within a single polypetide chain
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beta sheets
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stacks of pleated configurations between 2+ polypeptides
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disulfide bridges
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1. connect two regions within a protein
2. links two cysteine amino acid |
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chaperonins
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1. barrel shaped
2. envelop misfolded/unfolded proteins and fold them correctly |
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metal ions
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help with protein folding
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transcription and translation in PROKARYOTES
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1. no RNA processing
2. no exprot of RNA from nucleus to cytoplasm 3. operons 3. transcription and translation are coupled |
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transcription and translation in EUKARYOTES
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1. RNA processing
2. transcription occurs in nucleus 3. translation occurs in cytoplasm |
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adenine
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1. cyanide + ammonium ---> adenine
2. ubiquitous molecule (found in ATP, NAD, FAD, and a nitrogenous base) |
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Dr. Szostak's conclusion
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1. long chain fatty acids can form vesicles
2. small molecules can enter vesicles 3. nucleic acids are essential 4. nucleic acids can spontaneously polymerize 5. early genomes didn't store info |
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RNA fundamental to development of life:
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1. RNA pre-exists DNA
2. translation depends on RNA-based ribosomes (ribozymes) |
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Forms of gene expression regulation
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1. no regulation
2. enzyme level 3. translational level 4. transcriptional level |
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categories of transcriptional level gene regulation
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1. negative control
2. positive control |
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negative control
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activation/inactivation of repressor protein (target gene is repressed/not transcribed)
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induction - negative control
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1. when inducer-ligand is absent, repressor binds to DNA
2. not transcribed 3. ex: Lac operon (ligand: allolactose) |
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derepression - negative control
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1. when corepressor-ligand is present, it binds to repressor protein and then binds to DNA
2. not transcribed 3. ex: Arg operon (ligand: arginine) |
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positive control
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1. activation of activator protein
2. gene is expressed/transcribed |
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inducer - positive control
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1. inducer binds to activator which binds to activator region
2. transcription occurs 3. ex: mal operon (ligand: maltose) |
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Lac operon
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1. code for lactose utilization enzymes
2. Lac Z -degrades lactose; Lac Y imports lactose |
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lactose is absent
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1. lactose utilization enzymes not needed
2. repressor protein Lac I binds to operator region and blocks RNAP from transcribing genes |
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lactose is present
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1. lactose utilization enzymes needed
2. allolactose binds to repressor Lac I, preventing it from binding to operator so RNAP can transcribe genes |
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lactose and glucose present
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glucose is used first because it is easier to metabolize
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cAMP
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1. signal that increases in concentration when there are low levels of carbon (glucose)
2. binds to crp that binds to DNA to activate RNAP |
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lactose present and glucose absent
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transcription of genes in Lac operon occurs
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lactose present and glucose present
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transcription of genes in Lac operon does not occur
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lactose absent and glucose present
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transcription of genes in Lac operon does not occur
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lactose absent and glucose absent
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transcription of genes in Lac operon does not occur
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General Secretory Pathway
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1. series of secretary signals that guides a protein outside of the cell
2. signal is removed after protein has been secreted |
