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18 Cards in this Set
- Front
- Back
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What does it mean when it's said that the genetic code is "degenerate"?
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More than 1 codon can code for an amino acid.
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Summarize the genetic code in 7 characteristics.
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1) Triplet code
2) Degenerate 3) AUG is start codon 4) Non-overlapping 5) Arrangement in the table is not random 6) 3 stop codons {UAA, UAG, UGA} 7) Code is almost universal. |
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What does it mean when it's said that the genetic code is "overlapping"?
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Only 3 codons are read at a time.
EXA: AGAGGUGCU The sequence of 3 codons are read {AGA, GGU, GCU} *not* {AGA, GAG, AGG, etc...} |
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A codon is represented by a sequence of _____ bases.
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...3...
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What are the 3 types of RNA involved in translation, and what are their functions?
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mRNA (messenger) - Moves information from the nucleus to cytoplasm.
tRNA (transfer/decoder) - Matches codons to AA's rRNA (ribosomal/catalyst) - Catalyzes peptide bond formation. |
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Describe 4 general characteristics of the base sequence of tRNA.
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1) ~76 nucleotides (between 50-100)
2) many modified bases 3) 15 invariant positions 4) 8 semi-invariant positions |
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Describe 6 characteristics of tRNA secondary structure.
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Described from 5' end ---> 3' end
bp = base pair nt = nucleotide 1) 5' terminal phosphate group 2) 7 bp stem 3) D-Arm: 3-4 bp stem, 5-7 nt loop 4) Anticodon Arm: 5 bp stem and loop 5) TΨC Arm: 5 bp stem and loop ...7 bp stem 6) 3' CCA with free -OH |
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tRNA tertiary structure is shaped like what letter?
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An L.
L-shaped. |
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Name the product of the reaction:
Amino Acid + ATP ⇌ ? |
Aminoacyl-adenylate
i.e. aminoacyl-AMP |
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Name the product of the reaction:
AMinoacyl-AMP + tRNA ⇌ ? |
Aminoacyl-tRNA + AMP
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The non-abbreviated name of aatRNA is:
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aminiacyl-tRNA
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The majority of tRNA identity elements are found on the _____ and the _____.
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...acceptor-stem...
and ...anticodon... |
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Ribosomes are composed of _____ and _____.
What are their average percentages? |
RNA (66%)
protein (34%) |
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What are 5 general characteristics of translation?
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1) Ribosomes have 3 tRNA binding sites: E, P, A
2) Ppt synthesis proceeds from N-terminus to C-terminus - The COOH of the growing chain is linked to the NH₂ of the incoming AA. 3) Chain elongation transfers frowing chain (P-site) to incoming aa-tRNA (A-site) 4) Ribosomes read the mRNA from 5' to 3' 5) Translation takes place on polysomes. |
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The initiation complex forms at an AUG following a _____-_____ _____.
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Shine-Delgano Sequence (SDS)
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Shine-Delgano Sequence is recognized by _____ _____.
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...16S RNA.
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Describe the 3 steps of chain-elongation:
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1) Decoding - tRNA binding to A site
2) Transpeptidation - Peptide bond formation 3) P and A tRNA's are moved to E and P sites. |
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Describe the 5 steps of termination.
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1) RF 1 or 2 binds to stop codon in A site
2) Transfer of ppt. to H₂O. 3) RF 3-GTP binds, GTP hydrolysis, release of RF 1 or 2 4) RRF and EF-F-GTP bind, release RF-3-GDP 5) GTP hydrolysis, movement of tRNA to E-site, factors to P-site and release of tRNA, mRNA and factors. |
