BIOL2070 FINAL EXAM FLASHCARDS QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS
What is the central dogma?
All information passes only in one direction, so DNA to DNA, DNA to RNA, and RNA to
protein
What were the discoveries that have challenged the idea of the central dogma?
1. Reverse transcriptase - RNA can be transcribed back to DNA
2. Proteins can modify other proteins, creating prions
What are the steps to transcription?
1. Initiation
2. Elongation
3. Termination
Describe the initiation step in transcription
RNA polymerase binds to a promoter site
Describe the elongation step in transcription
RNA polymerase begins transcribing the mRNA from the 5' to 3' direction
Describe the termination step in transcription
RNA polymerase reaches the termination sequence, interacts with the polyA tail, and
releases the mRNA into the nucleus, which will be sent to the cytoplasm
Once an mRNA is made, it undergoes 3 steps. What are they, and describe their
purpose
, 1. 5' end capping - sugar bases attaches to the 5' end of the mRNA. This prevents
degradation
2. Addition of a polyA tail - lots of adenines attach to the mRNA. This increases stability
3. mRNA splicing to remove the introns. Prepares the mRNA before it gets translated
What are the 5' and 3' UTR? What are their functions?
The 5' and 3' untranslated regions are parts of the mRNA that do not get translated.
Instead, they control post-transcriptional gene regulation processes
What is pre-mRNA?
mRNA that contains both introns and exons
What are spliceosomes?
a ribonucleoprotein complex that removes the introns from pre-mRNA
What are snRNPs?
Small nuclear ribonucleoproteins that bind onto the introns of mRNA and squeeze them
out. They are the parts that make up the spliceosomes
What is the RNA lariat?
a lasso-like structure formed from the fragment of RNA to be removed during the
removal of introns
What enzyme joins together the exons?
RNA ligase
What is mature mRNA?
only exons present
What is post transcriptional control?
one gene can code for more than one protein because of alternative splicing
ANSWERS WITH COMPLETE SOLUTIONS
What is the central dogma?
All information passes only in one direction, so DNA to DNA, DNA to RNA, and RNA to
protein
What were the discoveries that have challenged the idea of the central dogma?
1. Reverse transcriptase - RNA can be transcribed back to DNA
2. Proteins can modify other proteins, creating prions
What are the steps to transcription?
1. Initiation
2. Elongation
3. Termination
Describe the initiation step in transcription
RNA polymerase binds to a promoter site
Describe the elongation step in transcription
RNA polymerase begins transcribing the mRNA from the 5' to 3' direction
Describe the termination step in transcription
RNA polymerase reaches the termination sequence, interacts with the polyA tail, and
releases the mRNA into the nucleus, which will be sent to the cytoplasm
Once an mRNA is made, it undergoes 3 steps. What are they, and describe their
purpose
, 1. 5' end capping - sugar bases attaches to the 5' end of the mRNA. This prevents
degradation
2. Addition of a polyA tail - lots of adenines attach to the mRNA. This increases stability
3. mRNA splicing to remove the introns. Prepares the mRNA before it gets translated
What are the 5' and 3' UTR? What are their functions?
The 5' and 3' untranslated regions are parts of the mRNA that do not get translated.
Instead, they control post-transcriptional gene regulation processes
What is pre-mRNA?
mRNA that contains both introns and exons
What are spliceosomes?
a ribonucleoprotein complex that removes the introns from pre-mRNA
What are snRNPs?
Small nuclear ribonucleoproteins that bind onto the introns of mRNA and squeeze them
out. They are the parts that make up the spliceosomes
What is the RNA lariat?
a lasso-like structure formed from the fragment of RNA to be removed during the
removal of introns
What enzyme joins together the exons?
RNA ligase
What is mature mRNA?
only exons present
What is post transcriptional control?
one gene can code for more than one protein because of alternative splicing
