BIOMG 3300 - Unit 8 Exam Prep
Questions Solved 100% Correct
RNA contribution to 3-D structure of ribosome - Answer The folding patterns of the rRNAs are
highly conserved in all organisms, particularly the regions implicated in key functions. There is
conservation of secondary structure in the small subunit rRNAs from three domains of life.
Ribosome in context of RNAworld hypothesis - Answer ...
tRNAs as adaptors - Answer They are called adaptor molecules because they are completely
attached to the ribosome-mRNA complex. They attach themselves via initiation and elongation
factors to the complex which facilitates the incorporation of the correct amino acid to the
growing polypeptide chain by its specific anticodon to the mRNA complex.
Structure and function of tRNA - Answer tRNAs are small and consist of a single strand of
RNA folded into a 3D structure. They vary in length from 73-93 nucleotides.
anticodon arm (or loop) - Answer Contains the anticodon. The loop contains seven
unpaired nucleotides.
TψC arm - Answer contains ribothymidine (T), not usually present in RNAs, and
pseudouridine (ψ), which has an unusual carbon-carbon bond between the base and ribose.
The TψC arm interacts with the large-subunit rRNA
the dihydrouracil arm (D arm) - Answer contains the unusual nucleotide dihydrouridine (D)
D and TψC arms contribute important interactions for the overall folding of tRNA molecules.
the 3' (CCA) and 5' ends of the tRNA molecule - Answer Most tRNAs have a guanylate (pG)
residue at the 5′ end, and all have the trinucleotide sequence CCA(3′) at the 3′ end.
, the position at which the amino acid is attached - Answer The amino acid arm 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.
regions that are hydrogen bonded - Answer tRNAs have a hydrogen-bonding pattern that forms
a cloverleaf structure with four arms; the longer tRNAs have a short fifth arm, or extra arm. In
three dimensions, a tRNA has the form of a twisted L
Amino Acid Activation - Answer 1 - Formation of an aminoacyl adenylate (aminoacyl-AMP,
an enzyme-bound intermediate) that remains bound to active site
2 - Aminoacyl group is transferred to the tRNA
aminoacyl-tRNA synthetase - Answer class of enzyme that loads amino acids onto tRNAs
Phosphoanhydride linkage - Answer the linkage that is broken in ATP
Mixed anhydride linkage - Answer the linkage that is formed in the activated
intermediate which is then broken in the final stage of the reaction
Ester linkage - Answer the linkage that is ultimately formed between the amino acid and the
tRNA
What is the other product of this series of reactions (activation of amino acid)? What
happens to this product? - Answer The other product of this series of reactions is the
pyrophosphate that undergoes hydrolysis to phosphate by inorganic pyrophosphatase.
balanced word equation for the sum of the activation and transfer steps, including hydrolysis
of PPi - Answer Amino Acid + rRNA + ATP -> aminoacyl-tRNA + AMP + 2Pi
deltaG = -29 kJ/mol
Questions Solved 100% Correct
RNA contribution to 3-D structure of ribosome - Answer The folding patterns of the rRNAs are
highly conserved in all organisms, particularly the regions implicated in key functions. There is
conservation of secondary structure in the small subunit rRNAs from three domains of life.
Ribosome in context of RNAworld hypothesis - Answer ...
tRNAs as adaptors - Answer They are called adaptor molecules because they are completely
attached to the ribosome-mRNA complex. They attach themselves via initiation and elongation
factors to the complex which facilitates the incorporation of the correct amino acid to the
growing polypeptide chain by its specific anticodon to the mRNA complex.
Structure and function of tRNA - Answer tRNAs are small and consist of a single strand of
RNA folded into a 3D structure. They vary in length from 73-93 nucleotides.
anticodon arm (or loop) - Answer Contains the anticodon. The loop contains seven
unpaired nucleotides.
TψC arm - Answer contains ribothymidine (T), not usually present in RNAs, and
pseudouridine (ψ), which has an unusual carbon-carbon bond between the base and ribose.
The TψC arm interacts with the large-subunit rRNA
the dihydrouracil arm (D arm) - Answer contains the unusual nucleotide dihydrouridine (D)
D and TψC arms contribute important interactions for the overall folding of tRNA molecules.
the 3' (CCA) and 5' ends of the tRNA molecule - Answer Most tRNAs have a guanylate (pG)
residue at the 5′ end, and all have the trinucleotide sequence CCA(3′) at the 3′ end.
, the position at which the amino acid is attached - Answer The amino acid arm 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.
regions that are hydrogen bonded - Answer tRNAs have a hydrogen-bonding pattern that forms
a cloverleaf structure with four arms; the longer tRNAs have a short fifth arm, or extra arm. In
three dimensions, a tRNA has the form of a twisted L
Amino Acid Activation - Answer 1 - Formation of an aminoacyl adenylate (aminoacyl-AMP,
an enzyme-bound intermediate) that remains bound to active site
2 - Aminoacyl group is transferred to the tRNA
aminoacyl-tRNA synthetase - Answer class of enzyme that loads amino acids onto tRNAs
Phosphoanhydride linkage - Answer the linkage that is broken in ATP
Mixed anhydride linkage - Answer the linkage that is formed in the activated
intermediate which is then broken in the final stage of the reaction
Ester linkage - Answer the linkage that is ultimately formed between the amino acid and the
tRNA
What is the other product of this series of reactions (activation of amino acid)? What
happens to this product? - Answer The other product of this series of reactions is the
pyrophosphate that undergoes hydrolysis to phosphate by inorganic pyrophosphatase.
balanced word equation for the sum of the activation and transfer steps, including hydrolysis
of PPi - Answer Amino Acid + rRNA + ATP -> aminoacyl-tRNA + AMP + 2Pi
deltaG = -29 kJ/mol
