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16 Cards in this Set
- Front
- Back
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RNA type(s) found in polysomes
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mRNA, tRNA and rRNA
A polysome (or polyribosome) consists of the mRNA transcript and all of the ribosomes that are translating it. |
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Before any kind of post-translational processing occurs, all polypeptides begin with the amino acid _____.
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Methionine (AUG)
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In Eukaryotes proteins are synthesized in the ____ and modified in the ____.
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Endoplasmic reticulum
Golgi Complex |
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How long, in amino acids, would be a polypeptide produced in the translation of a 24-base mRNA molecule?
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7
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In prokaryotes, the upstream mRNA sequence required for the initiation of protein synthesis is the ___ sequence.
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Shine-Dalgarno
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Common STOP codons (so no corresponding AA's)
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UAA
UAG UGA |
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START codon
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AUG (methionine)
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Given there are 20 amino acids and 4 nucleotides, what is the minimum size the genetic code can be?
A. 2 B. 4 C. 3 |
4^2 = 16 (too few)
4^4 = 256 (too many) 4^3 = 64 |
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The genetic code is:
A. triplet B. noncontinuous C. overlapping D. All of the above |
A - The genetic code can be considered triplet, continuous, non-overlapping and nearly universal
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The sequence of amino acids in a polypeptide chain determines the protein's ___ structure, while the number of polypeptide subunits determines its ______ structure.
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primary / quaternary
1. primary - sequence 2. secondary - regular folding 3. tertiary - 3-dimensional structure 4. quaternary - complex of polypeptide chain |
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What type of covalent bond joins the molecular building blocks in a protein?
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peptide bond btwn amino group and carboxyl group of next
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Where are phosphodiester bonds found?
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covalent bond in RNA & DNA btwn a sugar of 1 nucleotide and the phosphate of an adjacent nucleotide. They for the repeating sugar-phos array of the DNA/RNA backbone
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Which best represents the events that occur during translation?
A. DNA > mRNA B. mRNA > tRNA C. rRNA > protein D. mRNA > protein |
During translation, ribosomes "read" the message carried from the nucleus by mRNA molecules and convert it into a sequence of amino acids.
A. DNA > mRNA = transcription B. mRNA > tRNA = no, tRNA transfers AA's to ribosomes C. rRNA > protein = makes up ribosomes w/ ribo proteins. Ribo's are where mRNA is translated to produce a polypeptide |
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Which event occurs at the beginning of translation?
A. the polypeptide is released from the ribosome B. tRNA is released from the amino acid C. mRNA binds to ribosome D. rRNA binds to a ribosome |
C. mRNA binds to a ribosome because this is where it's translated.
Ribosomes attach in the region of the AUG codon in the mRNA transcript at the initiation of translation. |
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The longevity of a eukaryotic mRNA molecule is dependent on its:
A. 5' G-cap B. sequence length C. poly-A tail D. Shine-Dalgarno sequence |
C. poly-A tail: the length of the tail helps regulate mRNA longevity
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What type of nucleic acid is a structural component of ribosomes?
A. DNA B. rRNA C. tRNA D. all of the above |
rRNA - Only ribosomal RNA is an actual component of ribosomes. Transfer RNA is only transiently associated with a ribosome during the elongation phase of translation
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