Term
| Distinguish between overlapping and nonoverlapping codes. |
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Definition
| Overlapping codes allow bacteria to synthesize several proteins from a small set of genes. Nonoverlapping codes require humans to have longer genes. |
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Term
| Distinguish between conitnous and punctuated codes. |
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Definition
| Continuous codes contain no introns, they have already been spliced |
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Term
| How many amino acids do humans have? How many codons? What does this discrepancy cause? |
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Definition
| 20 AA's; 64 codons; Redundancy |
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Term
| What are the only two amino acids that have a unique code? How often are they used in proteins? |
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Definition
| Tryptophan & Methionine; least often of all AA's |
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Term
| What term describes the fact that there may be several tRNA's that carry a given amino acid? |
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Definition
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Term
| How many codons code for an amino acid? |
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Definition
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Term
| Which end is the business end of tRNA? What nucleotide will always be at this end? |
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Definition
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Term
| T/F Each tRNA is specificly binds to a single amino acid. |
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Definition
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Term
| What interprets the second genetic code? |
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Definition
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Term
| Which amino acids often take the place of each other by accident? |
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Definition
| Isoleucine & Valine (differ by one methyl group) |
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Term
| What is the overal reaction of aminoacyl-tRNA synthetase? |
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Definition
| uses energy from breaking two high enrgy ATP bonds (expensive) to form 3'-ester linking amino acid to its cognate tRNA. |
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Term
| Is the codon on the mRNA or tRNA? Anticodon? |
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Definition
| Codon = mRNA; Anticodon = tRNA |
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Term
| What is the term for the following: First two bases of codon form strong base pairs with corresponding bases of anticodon. Third base of codon pairs loosely with corresponding base of its anticodon? |
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Definition
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Term
| Which bases bind more specifically/stronger? |
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Definition
| C & A are more specifica than U & G |
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Term
| What is the proportion of RNA to protein in ribosomes? What percent of a cell's mass do they make up? Do prokaryotes or eukaryotes have larger ribosomes? |
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Definition
| 2/3 RNA & 1/3 protein; 20% of a cell; Eukaryotes are larger |
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Term
| What are the three major properties of ribosomes? |
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Definition
1. Cationic proteins which play a structural role
2. Eukaryotic rRNA originates in Nucleolus
3. Spontaneous Assembly |
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Term
| What area of the small ribosomal subunit ensures the message is in the correct place? |
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Definition
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Term
| What location on the large ribosomal subunit is where the arriving amino acid will be handed over to the growing polypeptide chain? |
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Definition
| Peptidyl transferase center |
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Term
| What is defines as multiple ribosomes translating the same mRNA? |
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Definition
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Term
| Which site is where tRNA comes in? In which site does the growing polypeptide chain reside? From which site is the polypeptide chain released? |
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Definition
| into A site; grows at P site; exits from E site |
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Term
| What is the unique tRNA that is required for prokaryote initiation? |
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Definition
| N-formyl-methionyl-tRNAifMet |
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Term
| In eukaryotes, what interacts with the rRNA to always ensure that the message is in the correct place without exception? |
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Definition
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Term
| Does the large ribosomal subunit attach before or after the other factors have left the complex? |
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Definition
| After; they must get out of the way for it to bind |
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Term
| What type of energy is used in the peptidyl transfer and ribosome translocation? |
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Definition
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Term
| What enzyme transfers the amino acid from the P site tRNA to the A site tRNA? |
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Definition
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Term
| What proteins recognize the stop codon at the A site? |
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Definition
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Term
| What transforms the peptidyl transferase into a hydrolase? What is the result of this? |
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Definition
| presence of release factors with a nonsense codon at the A site --> cleaves peptidyl chain from tRNA carrier |
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Term
| Is IF-3 released before or after addition of 50S unit? |
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Definition
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Term
| What codon invariably signals the translation start site? |
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Definition
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Term
| What complex ensures the correct placement of translated region by holding non-translated 5' & 3' ends? |
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Definition
| Eukaryotic Preinitiation Complex |
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Term
| What ejects IF's and leads to 60S coupling? |
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Definition
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Term
| What is the normal level of incorrect insertions? |
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Definition
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Term
| How many high-energy phosphate bonds are expended per amino acid residue added to a nascent protein chain? |
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Definition
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Term
| What is an aminoglycoside antibiotic that induces mRNA misreading resulting in mutant proteins that slow bacterial growth rate? |
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Definition
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Term
| What antbiotic binds the A site of both pro & eukaryotic ribosomes accepting the peptide chain from the P site & terminating protein synthesis? |
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Definition
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Term
| What NAD-dependent ADP ribosylase targets EF-2 enzyme & inhibits protein synthesis? |
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Definition
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