PRACTICE EXAM #3 Flashcards
Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell?
Allolactose binds to the repressor protein.
true or false: A ribosome binds one tRNA at a time.
false
true or false: Ubiquitin is a small protein that is covalently attached to proteins to mark them for delivery to the proteasome.
true
Examples of a pair of codons expected to be read by the same tRNA because the Wobble effect areCAA and _______________
CAU
CAG
CAC
Which level control in eukaryotic gene activity involves changes in the polypeptide chain before it becomes functional such as adding phosphate groups?
Posttranslational
If mature eukaryotic mRNA is hybridized with its corresponding DNA coding strand (heteroduplex analysis) and visualized by electron microscopy, looping strands of nucleic acid are seen. What do these structure represent?
introns
Which level of of control in gene expression regulation is very comon in both prokariotes and eukaryotes?
transcriptional like using activators and repressors
true or false: Ribosomes are large RNA structures composed solely of rRNA.
false
Which of the classes of RNA molecules is linked with proteins in forming the large and small subunits of a cytoplasmic structure?
ribosomal RNA
While prokaryotes are polycystronic, they also have a _______ sequence to bind to the ribosome upstream form the AUG starting code.
Shine-Dalgarno sequence
PAP and poly-A binding protiens are related with:
the 3’ terminal of the mRNA
With your expert opinion, what do you think it would happen if snRNA are produced but are mutated?
no formation of splisosomes
A transcriptional regulator that decreases transcription of a gene from a vast distance is known as a(n)
repressor-silencer.
Ribozymes catalyze the reactions ________________, _____________
- splicing
- translation
true or false: Ribosomes can start translating an mRNA molecule before transcription is complete.
true