Gene Expression in Prokaryotes and Eukaryotes Quiz 3

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which statement correctly describes the process of translation in eukaryotes?

Translation does not involve ribosomal subunits.

Translation occurs cotranscriptionally.

Translation begins with a short mRNA sequence. (correct)

Translation is completed before transcription ends.

What is the role of sigma factors in prokaryotes?

They act as cis-acting elements.

They are involved in ribosomal assembly.

They serve as trans-acting factors that modify RNA.

They bind to the promoter region to initiate transcription. (correct)

Which of the following is NOT a characteristic of prokaryotic genes?

They lack complex regulatory regions.

They have a single start codon.

They do not contain introns.

They are typically monocistronic. (correct)

Which element is an example of a cis-acting regulatory sequence in eukaryotes?

Enhancer Signup and view all the answers

What characteristic of the genetic code means that each nucleotide can only be included once in a codon?

Non-overlapping Signup and view all the answers

Which transcription termination mechanism is characterized by the formation of a hairpin structure in the mRNA?

Intrinsic transcription termination Signup and view all the answers

What distinguishes prokaryotic and eukaryotic transcription regulation?

Eukaryotes have multiple RNA polymerases. Signup and view all the answers

The major difference in translation initiation between prokaryotes and eukaryotes can be described as:

Eukaryotic translation requires multiple initiation factors. Signup and view all the answers

What is the role of the IF2 initiation factor in bacterial translation?

To bring the initiator tRNA to the P site Signup and view all the answers

Which of the following statements about elongation factors in bacterial translation is correct?

EF-Tu delivers tRNAs to the A site. Signup and view all the answers

Which codon functions as a stop signal in mRNA?

UAA Signup and view all the answers

What are enhancers, silencers, and insulators categorized as in eukaryotic genetics?

Types of distal promoters Signup and view all the answers

During mRNA processing in eukaryotes, which of the following does NOT occur?

Replication of mRNA Signup and view all the answers

Which of the following is NOT a mechanism that can lead to alternative splicing of a primary transcript?

Transcription termination Signup and view all the answers

What specific feature ensures that each codon codes for only one single amino acid?

Specific coding Signup and view all the answers

What is the main function of the cleavage and polyadenylation specific factor (CPSF) in eukaryotic transcription?

To bind RNAP II for termination Signup and view all the answers

Study Notes

Quiz 3: Gene Expression in Prokaryotes and Eukaryotes

True/False Questions (3 points each):
- In eukaryotes, translation does not occur co-transcriptionally.
- A trans-acting factor is any protein that is synthesized from a mRNA.
- The genetic code uses one codon as a start signal (AUG) and three codons as stop signals (UAA, UAG, UGA).
- In prokaryotes, the 30S initiation complex includes the 30S ribosomal subunit, initiation factors 1-3, and the initiator tRNA.
- The majority of eukaryotic genes are monocistronic.
- Prokaryotic genes are typically intronless.
- Eukaryotes have multiple RNA polymerases, including three nuclear types and additional ones in mitochondria and chloroplasts.
- A promoter is an example of a trans-acting factor (rather than a cis-acting factor).
- Sigma factors and general transcription factors are examples of trans-acting proteins.
- In eukaryotes, enhancers are cis-acting elements.
- The core promoter in eukaryotes includes elements like the TATA box, CAAT box, and GC box.
- The RNA-coding regions of prokaryotes and eukaryotes are relatively similar.
- In eukaryotes, mRNA processing involves 5' capping, splicing, and 3' end processing (cleavage & polyadenylation).
- Initiation differs between prokaryotic and eukaryotic translation, the processes of elongation and termination are very similar.

Fill in the Blank (4 points each):

Consensus sequence: a term that describes the sequence of nucleotides common at a site.
Cis-acting element: a DNA sequence with regulatory functions, often a binding site for proteins that regulate gene expression.
Sigma domain 2: a sigma factor domain that interacts with the non-template strand to allow DNA melting for RNA polymerase binding.
Intrinsic transcription termination: a prokaryotic mechanism involving a GC-rich palindromic sequence followed by adenines, which forms a hairpin loop.
Non-overlapping: the feature of the genetic code where each nucleotide is only used once per codon.

Additional Concepts (Referencing Page 2):

Genetic code features:
- Each codon corresponds to a specific amino acid.
- The genetic code is unambiguous, meaning a codon only designates one specific amino acid.
Initiation factor IF2 (bacteria): Binds the initiator tRNA to the small ribosomal subunit (30S).
Elongation Steps (bacteria): Decoding, peptide bond formation, and translocation.
Elongation factor EF-Tu (bacteria): Transports aminoacyl-tRNAs to the A site of the ribosome.
Elongation factor EF-G (bacteria): Facilitates the translocation of ribosomes along the mRNA.
Translocation of ribosomes: movement of the ribosome on the mRNA during translation.
Distal promoters: such as enhancers and silencers, and insulators are common eukaryotic distal regulators.
Termination of eukaryotic transcription: The cleavage and polyadenylation specific factor (CPSF) are involved in eukaryotic transcription termination.
Alternative Splicing: various mechanisms enable different splicing outcomes from one primary transcript, for example: exon skipping, alternative 5' or 3' splice sites, mutually exclusive exons, intron retention, alternative promoter usage, or alternative polyadenylation.

Diagrams:

Prokaryotic gene structure: Shows the promoter, regulatory sequence, 5' untranslated region (UTR), coding region (ORF), 3' UTR, and terminator.
Eukaryotic mRNA structure: Highlights exons, introns, 5' and 3' UTRs, upstream and downstream regulatory elements, start and stop codons, and polyadenylation sequence (PAS).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on gene expression mechanisms in both prokaryotic and eukaryotic organisms with this true/false quiz. Review key concepts such as transcription, translation, and the role of various factors involved in the process. Challenge yourself with questions that cover both foundational and intricate details of gene expression.