Term
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Definition
| when amino acids become attached to a heat-stable soluble RNA (transfer RNA) |
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Term
| aminoacyl-tRNA synthetases |
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Definition
| the enzymes that catalyze the process that forms aminoacyl-tRNAs |
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Term
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Definition
| the overall process of mRNA-guided protein synthesis |
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Term
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Definition
| a triplet of nucleotides that codes for a specific amino acid |
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Term
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Definition
| established by a specific first codon in the sequence; a new codon begins in the reading frame every three nucleotide residues |
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Term
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Definition
| AUG - the most common signal for the beginning of a polypeptide in all cells (also codes for Met residues in internal positions of polypeptides) |
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Term
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Definition
| AKA stop codons or nonsense codons, they normally signal the end of polypeptide synthesis & do not code for any known amino acids |
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Term
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Definition
| a reading frame without a termination codon among 50 or more codons |
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Term
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Definition
| the feature of the genetic code in that an amino acid may be specified by more than one codon |
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Term
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Definition
| a three-base sequence on the tRNA where transfer RNAs can base-pair with mRNA codons |
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Term
| 4 relationships described in the wobble hypothesis |
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Definition
1. the first two bases of an mRNA codon always form strong Watson-Crick base pairs with the corresponding bases of the tRNA anticodon & confer most of the coding specificity
2. the first base of the anticodon determines the number of codons recognized by the tRNA
3. when an amino acid is specified by several different codons, the codons that differ in either of the first two bases require different tRNAs
4. a minimum of 32 tRNAs are required to translate all 61 codons |
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Term
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Definition
| the most common kinds of mutations which has deleterious effects; a single new base pair replaces another |
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Term
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Definition
| the most frequent missense mutation due to the types of spontaneous DNA damage that affect genomes; a purine is replaced by a purine or a pyrimidine by a pyrimidine |
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Term
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Definition
| can involve the addition, deletion, or alteration of nucleotides in the RNA in a manner that affects the meaning of the transcript when it is translated |
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Term
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Definition
| stands for the "adenosine deaminases that act on RNA" that carry out the adenosine deamination reactions |
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Term
| What is the relationship between APOBEC & AID? |
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Definition
| The cytidine deaminations are carried out by the APOBEC family of enzymes, which includes the related AID enzymes |
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Term
| 5 steps of protein biosynthesis |
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Definition
1. activation of amino acids
2. initiation
3. elongation
4. termination & ribosome recycling
5. folding & posttranslational processing |
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Term
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Definition
| can carry a specific amino acid esterified by its carboxyl group to the 2'- or 3'-hydroxyl group of the A residue at the 3' end of the tRNA |
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Term
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Definition
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Term
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Definition
| a major arm on the tRNA; contains the unusual nucleotide dihydrouridine |
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Term
| 7 things required for initiation of polypeptide synthesis in bacteria |
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Definition
1. the 30S ribosomal subunit
2. the mRNA coding for the polypeptide to be made
3. the initiating fMet-tRNA
4. a set of three proteins called initiation factors
5. GTP
6. the 50S ribosomal subunit
7. Mg2+ |
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Term
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Definition
| guides the initiating AUG to its correct position; in the mRNA |
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Term
| What is the relationship between the aminoacyl (A) site, the peptidyl (P) site, & the exit (E) site? |
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Definition
| Bacterial ribosomes have three sites that bind tRNAs, the A site, the P site, & the E site |
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Term
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Definition
| a functional 70S ribosome; contains the mRNA & the initiating fMet-tRNA |
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Term
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Definition
| the third stage of protein synthesis |
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Term
| 4 things required for elongation |
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Definition
1. the initiation complex
2. aminoacyl-tRNAs
3. a set of three soluble cytosolic proteins called elongation factors
4. GTP |
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Term
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Definition
1. binding of an incoming aminoacyl-tRNA
2. peptide bond formation
3. translocation |
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Term
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Definition
| the enzymatic activity that catalyzes peptide bond formation |
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Term
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Definition
| the final step of the elongation cycle; the ribosome moves one codon toward the 3' end of the mRNA |
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Term
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Definition
| the fourth stage of polypeptide synthesis & is signaled by the presence of one of three termination codons in the mRNA immediately following the final coded amino acid |
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Term
| 3 things triggered by termination factors (release factors)once a termination codon occupies the ribosomal A site |
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Definition
1. hydrolysis of the terminal peptidyl-tRNA bond
2. release of the free polypeptide & last tRNA (now uncharged) from the P site
3. dissociation of the 70S ribosome into its 30S & 50S subunits |
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Term
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Definition
| one of the best-understood inhibitory antibiotics |
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Term
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Definition
| inhibit protein synthesis in bacteria by blocking the A site on the ribosome, preventing the binding of aminoacyl-tRNAs |
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Term
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Definition
| inhibits protein synthesis by bacterial ribosomes by blocking peptidyl transfer; it does not affect protein synthesis in eukaryotes |
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Term
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Definition
| blocks the peptidyl transferase of 80S eukaryotic ribosomes but not that of 70S bacterial ribosomes |
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Term
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Definition
| causes misreading of the genetic code at relatively low concentrations & inhibits initiation at higher concentrations |
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Term
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Definition
| catalyzes the ADP-ribosylation of a diphthamide residue of the eukaryotic elongation factor eEF2, thereby inactivating it |
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Term
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Definition
| an extremely toxic protein of the castor bean which inactivates the 60S subunit of eukaryotic ribosomes by depurinating a specific adenosine in 23 rRNA |
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