Molecular Biology Exam queries and
answers graded A+
Ways in which RNA is processed in eukaryotic cells. - ANS✅✅1. 5' cap
2. Splicing
3. Polyadenine tail
The component(s) of an mRNA's 5' cap - ANS✅✅7-methyl guanosine
5'-5' triphosphate linkage
The mechanism that attracts various machinery to modify pre-mRNA - ANS✅✅Phosphorylation
state of CTD tail
Functions of the 5' mRNA cap - ANS✅✅1. Protection from 5' exonucleases
2. Increased ribosomal recognition
Experiments that revealed the genes-in-pieces hypothesis - ANS✅✅DNA-mRNA hybdridization
revealing R-loops
Contents of the spliceosome - ANS✅✅1. pre-mRNA
2. snRNPs (e.g., Ux riboproteins)
3. Additional splicing factors
First step of splicing reaction - ANS✅✅U2-BBP exchange
Second step of splicing reaction - ANS✅✅U6-U1 exchange to bring the U4-6 complex onto the pre-
mRNA
Third step of splicing reaction - ANS✅✅U4 ejection, creation of active site by U2 and U6
Fourth step of splicing reaction - ANS✅✅U5 hydrolyzes ATP to join ends of exons
, Components of the E phase of the spliceosome - ANS✅✅U1, BBP, etc.
Components of the A phase of the spliceosome - ANS✅✅U1, U2, etc.
Components of the B phase of the spliceosome - ANS✅✅U2, U4-6
Components of the C phase of the spliceosome - ANS✅✅U2, U5, U6
Example(s) of alternative splicing from class - ANS✅✅Dscam, troponin T
Enzyme responsible for adding amino acids to tRNA molecules - ANS✅✅Aminoacyl-tRNA
synthetase
Definition of an ORF - ANS✅✅A section of *mRNA* bounded by start and stop codons
Definition of polycistronic - ANS✅✅A type of mRNA that contains multiple ORFs; typical of
prokaryotes
Definition of monocistronic - ANS✅✅A type of mRNA that contains *only one* ORFs; typical in
eukaryotes
Prokaryotic RBS - ANS✅✅Shine-Dalgarno sequence
The first amino acid in a prokaryotic polypeptide chain - ANS✅✅*f*Met
Five common features of *all* tRNAs - ANS✅✅1. 3' overhang (CCA)
2. Dihydrouridine loop
3. Pseudouridine loop
4. Presence of a variable loop
5. Anticodon loop
Function(s) of aminoacyl tRNA synthetases - ANS✅✅1. Adenylylation of amino acids
answers graded A+
Ways in which RNA is processed in eukaryotic cells. - ANS✅✅1. 5' cap
2. Splicing
3. Polyadenine tail
The component(s) of an mRNA's 5' cap - ANS✅✅7-methyl guanosine
5'-5' triphosphate linkage
The mechanism that attracts various machinery to modify pre-mRNA - ANS✅✅Phosphorylation
state of CTD tail
Functions of the 5' mRNA cap - ANS✅✅1. Protection from 5' exonucleases
2. Increased ribosomal recognition
Experiments that revealed the genes-in-pieces hypothesis - ANS✅✅DNA-mRNA hybdridization
revealing R-loops
Contents of the spliceosome - ANS✅✅1. pre-mRNA
2. snRNPs (e.g., Ux riboproteins)
3. Additional splicing factors
First step of splicing reaction - ANS✅✅U2-BBP exchange
Second step of splicing reaction - ANS✅✅U6-U1 exchange to bring the U4-6 complex onto the pre-
mRNA
Third step of splicing reaction - ANS✅✅U4 ejection, creation of active site by U2 and U6
Fourth step of splicing reaction - ANS✅✅U5 hydrolyzes ATP to join ends of exons
, Components of the E phase of the spliceosome - ANS✅✅U1, BBP, etc.
Components of the A phase of the spliceosome - ANS✅✅U1, U2, etc.
Components of the B phase of the spliceosome - ANS✅✅U2, U4-6
Components of the C phase of the spliceosome - ANS✅✅U2, U5, U6
Example(s) of alternative splicing from class - ANS✅✅Dscam, troponin T
Enzyme responsible for adding amino acids to tRNA molecules - ANS✅✅Aminoacyl-tRNA
synthetase
Definition of an ORF - ANS✅✅A section of *mRNA* bounded by start and stop codons
Definition of polycistronic - ANS✅✅A type of mRNA that contains multiple ORFs; typical of
prokaryotes
Definition of monocistronic - ANS✅✅A type of mRNA that contains *only one* ORFs; typical in
eukaryotes
Prokaryotic RBS - ANS✅✅Shine-Dalgarno sequence
The first amino acid in a prokaryotic polypeptide chain - ANS✅✅*f*Met
Five common features of *all* tRNAs - ANS✅✅1. 3' overhang (CCA)
2. Dihydrouridine loop
3. Pseudouridine loop
4. Presence of a variable loop
5. Anticodon loop
Function(s) of aminoacyl tRNA synthetases - ANS✅✅1. Adenylylation of amino acids
