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Questions and Answers
Using the image, determine the total number of exons contained in the unknown gene.
Using the image, determine the total number of exons contained in the unknown gene.
6
Using the image, determine the total number of introns contained in the unknown gene.
Using the image, determine the total number of introns contained in the unknown gene.
5
Why is a cap added to mRNA, but not to tRNA or rRNA?
Why is a cap added to mRNA, but not to tRNA or rRNA?
Each of the three types of RNA are transcribed by different RNA polymerases. Only RNA polymerase II, involved in mRNA synthesis, contains a domain capable of interacting with enzymes that form the cap.
What is the function of the spliceosome?
What is the function of the spliceosome?
In eukaryotic gene regulation, RNA interference occurs through?
In eukaryotic gene regulation, RNA interference occurs through?
Explain why the hybrid gene mRNA transcript does not undergo 3' cleavage and polyadenylation.
Explain why the hybrid gene mRNA transcript does not undergo 3' cleavage and polyadenylation.
Where is the most likely location of the 5' untranslated region on the DNA and RNA molecule?
Where is the most likely location of the 5' untranslated region on the DNA and RNA molecule?
Where would the 3' untranslated region be located on the DNA and RNA molecule?
Where would the 3' untranslated region be located on the DNA and RNA molecule?
Classify each description as true of introns only, true of exons only, or true of both introns and exons.
Classify each description as true of introns only, true of exons only, or true of both introns and exons.
What are the true statements regarding mRNA splicing?
What are the true statements regarding mRNA splicing?
Label the structural features of the yeast phenylalanine tRNA.
Label the structural features of the yeast phenylalanine tRNA.
Assign the RNA regulation consequences to the type of deletion most likely to result in the consequence.
Assign the RNA regulation consequences to the type of deletion most likely to result in the consequence.
Select the best explanation for how overexpression of CHS silences expression of CHS.
Select the best explanation for how overexpression of CHS silences expression of CHS.
Match each pre-mRNA processing function with its appropriate type.
Match each pre-mRNA processing function with its appropriate type.
Identify the true statements about RNA interference.
Identify the true statements about RNA interference.
What does it mean for bacterial genes to be colinear?
What does it mean for bacterial genes to be colinear?
One purpose of the 5' untranslated region of mRNA is _____?
One purpose of the 5' untranslated region of mRNA is _____?
The most abundant form of RNA inside the cell is _____ RNA.
The most abundant form of RNA inside the cell is _____ RNA.
Inhibition of gene expression triggered by double-stranded RNA molecules is termed RNA ____.
Inhibition of gene expression triggered by double-stranded RNA molecules is termed RNA ____.
Which statement correctly describes the critical observation that disproved rRNA as the intermediary molecule?
Which statement correctly describes the critical observation that disproved rRNA as the intermediary molecule?
Which site does not play a role in the successful removal of an intron from mRNA?
Which site does not play a role in the successful removal of an intron from mRNA?
The adapter molecule that serves as a link between the genetic code in mRNA and the amino acids that make up a protein is _____ RNA.
The adapter molecule that serves as a link between the genetic code in mRNA and the amino acids that make up a protein is _____ RNA.
Which of the following is involved in RNA interference?
Which of the following is involved in RNA interference?
In the experiment showing the noncolinearity of eukaryotic genes, was the DNA or RNA molecule longer?
In the experiment showing the noncolinearity of eukaryotic genes, was the DNA or RNA molecule longer?
Removal of introns from a pre-mRNA molecule in eukaryotes is termed RNA ____.
Removal of introns from a pre-mRNA molecule in eukaryotes is termed RNA ____.
What feature is most critical to tRNA function?
What feature is most critical to tRNA function?
What is the likely function of a long noncoding RNA that has several mRNA binding sites?
What is the likely function of a long noncoding RNA that has several mRNA binding sites?
Which of the following types of genes would typically contain only nucleotide sequences designed for amino acid sequence of a protein?
Which of the following types of genes would typically contain only nucleotide sequences designed for amino acid sequence of a protein?
Which of the following is/are not found in mature mRNA molecules in eukaryotes?
Which of the following is/are not found in mature mRNA molecules in eukaryotes?
True or false? Bacterial and eukaryotic ribosomes each consist of a large subunit and small subunit.
True or false? Bacterial and eukaryotic ribosomes each consist of a large subunit and small subunit.
CRISPR RNAs in bacteria function like what system in the human body?
CRISPR RNAs in bacteria function like what system in the human body?
Based on the experiment with hybridization, the gene must contain _____ exons and _____ introns.
Based on the experiment with hybridization, the gene must contain _____ exons and _____ introns.
Which mechanism produces, from a single gene, multiple mRNAs of different lengths encoding different polypeptides? Choose all that apply.
Which mechanism produces, from a single gene, multiple mRNAs of different lengths encoding different polypeptides? Choose all that apply.
True or false? When a 20S ribosomal subunit combines with a 30S subunit, the resulting complex will be 50S.
True or false? When a 20S ribosomal subunit combines with a 30S subunit, the resulting complex will be 50S.
How are miRNAs and siRNAs similar?
How are miRNAs and siRNAs similar?
Which of the following facts about introns and exons are not true?
Which of the following facts about introns and exons are not true?
The structure below is an intermediate in which process? (Choose: translation, polyadenylation, RNA splicing, transcription, replication)
The structure below is an intermediate in which process? (Choose: translation, polyadenylation, RNA splicing, transcription, replication)
What is the correct sequence of events leading to successful RNA splicing?
What is the correct sequence of events leading to successful RNA splicing?
Why might RNA interference be critical in embryonic development?
Why might RNA interference be critical in embryonic development?
Introns of which type of RNA are removed by spliceosomes?
Introns of which type of RNA are removed by spliceosomes?
What mechanism can explain a geneticist identifying an mRNA molecule with the 5′ end from a gene on chromosome 3 and the 3′ end from a gene on chromosome 6?
What mechanism can explain a geneticist identifying an mRNA molecule with the 5′ end from a gene on chromosome 3 and the 3′ end from a gene on chromosome 6?
What would likely happen to the function of tRNA if the sequence of the 3' end was mutated?
What would likely happen to the function of tRNA if the sequence of the 3' end was mutated?
How is siRNA different than miRNA?
How is siRNA different than miRNA?
The sequences on a eukaryotic gene that are represented in mature mRNAs are called ____.
The sequences on a eukaryotic gene that are represented in mature mRNAs are called ____.
What is the most likely effect of the mutation changing the branch point A within an intron to a U?
What is the most likely effect of the mutation changing the branch point A within an intron to a U?
Which rRNA component is likely to be part of a 40S ribosomal subunit?
Which rRNA component is likely to be part of a 40S ribosomal subunit?
If a gene were arranged like the figure below, how many different mRNAs, with at least two exons, are possible through alternative splicing?
If a gene were arranged like the figure below, how many different mRNAs, with at least two exons, are possible through alternative splicing?
Which of the following statements is true about gene structure?
Which of the following statements is true about gene structure?
All of the following ribosomal RNA components are produced from cleavage of the 30S rRNA precursor, except ____.
All of the following ribosomal RNA components are produced from cleavage of the 30S rRNA precursor, except ____.
The diagram below shows a DNA molecule hybridized with an RNA molecule. The loop in the DNA molecule indicates the presence of a(n) ____.
The diagram below shows a DNA molecule hybridized with an RNA molecule. The loop in the DNA molecule indicates the presence of a(n) ____.
How is the following statement incorrect? 'A gene is a sequence of nucleotides that encode amino acids in a protein.'
How is the following statement incorrect? 'A gene is a sequence of nucleotides that encode amino acids in a protein.'
Which mechanism allows rare bases to be incorporated into tRNA molecules?
Which mechanism allows rare bases to be incorporated into tRNA molecules?
You are running a transcription reaction in your lab. You stop the reaction after a few minutes and find that you have three predominant DNA and RNA molecules in your test tube. All have different lengths. Which molecule is likely the pre-mRNA?
You are running a transcription reaction in your lab. You stop the reaction after a few minutes and find that you have three predominant DNA and RNA molecules in your test tube. All have different lengths. Which molecule is likely the pre-mRNA?
Which letter in the diagram below indicates the site at which amino acids attach to this molecule?
Which letter in the diagram below indicates the site at which amino acids attach to this molecule?
Are all eukaryotic genes colinear?
Are all eukaryotic genes colinear?
Which is the most precise definition of a gene?
Which is the most precise definition of a gene?
What is a codon?
What is a codon?
What is the Shine-Dalgarno sequence?
What is the Shine-Dalgarno sequence?
Which is not a characteristic of the 5' cap?
Which is not a characteristic of the 5' cap?
What is necessary for the addition of the poly(A) tail?
What is necessary for the addition of the poly(A) tail?
Which mRNA sequence does not play a role in intron splicing?
Which mRNA sequence does not play a role in intron splicing?
Which is not found in a spliceosome that is actively splicing?
Which is not found in a spliceosome that is actively splicing?
Which is not a variation of splicing?
Which is not a variation of splicing?
Alternative splicing produces?
Alternative splicing produces?
Which is not a type of pre‑mRNA processing in eukaryotes?
Which is not a type of pre‑mRNA processing in eukaryotes?
What is the outcome of RNA editing?
What is the outcome of RNA editing?
What is the role of the acceptor arm of the tRNA molecule?
What is the role of the acceptor arm of the tRNA molecule?
Which statement is not correct about how siRNAs and miRNAs function?
Which statement is not correct about how siRNAs and miRNAs function?
What are CRISPR RNAs?
What are CRISPR RNAs?
Study Notes
Gene Structure and RNA Processing
- Unknown gene contains 6 exons and 5 introns based on hybridization results.
- Eukaryotic genes generally have non-coding regions (introns) removed during mRNA maturation.
- mRNA has a 5' cap added for stability and ribosome binding, a modification not present in tRNA or rRNA.
RNA Interference and Splicing
- RNA interference (RNAi) is a gene-silencing mechanism initiated by double-stranded RNA (dsRNA).
- Steps include: introduction of dsRNA, cleavage into short dsRNA, binding with RISC, degradation of the sense strand, pairing of antisense strand with target mRNA, and silencing of gene expression.
- The spliceosome is responsible for removing introns and joining exons to generate mature mRNA.
mRNA Modifications
- Polyadenylation at the 3' end stabilizes mRNA, prevents degradation, and aids in ribosome binding.
- Deleting the AAUAAA consensus sequence prevents cleavage at the polyadenylation site; deletion of the poly(A) tail affects mRNA cytoplasmic transport; removing the 5' cap leads to intron retention.
Alternative Splicing and Gene Regulation
- Alternative splicing allows a single gene to produce multiple mRNA variants, leading to different protein products.
- RNAs associated with gene expression regulation include miRNA, which blocks translation of specific mRNAs.
Properties of tRNA and Ribosomes
- tRNA's critical features include its secondary structure and specific binding at the 3' end for amino acids.
- Ribosomes consist of large and small subunits in both bacteria and eukaryotes, with specific rRNA components.
Experimental Observations in Gene Studies
- The non-colinearity of eukaryotic genes is demonstrated by comparing the lengths of DNA and corresponding mRNA.
- DNA is longer than mRNA due to the presence of introns in the former.
- Trans-splicing can occur, combining exons from different genes, illustrating the complexity of RNA maturation.
Functions and Mechanisms
- CRISPR RNAs in bacteria provide a form of defense similar to an immune system in higher organisms.
- Modification of tRNA bases ensures functionality during protein synthesis.
- siRNA may inhibit transcription while miRNA primarily acts on mRNA translation.
Molecular Mechanisms and Effects of Mutations
- Mutations affecting branch points in introns can lead to longer mRNA and abnormal protein products due to ineffective splicing.
- RNA editing can alter the protein product translated from the mRNA, sometimes resulting in a sequence distinct from that encoded by the gene.
Summary of mRNA and Genetic Concepts
- Exons are retained in mature mRNA, while introns are removed through splicing.
- Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids in proteins.
- The Shine-Dalgarno sequence is crucial for ribosome binding in bacterial translation.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of DNA-RNA hybridization experiments and gene structure with these flashcards from Chapter 14. This quiz will help you explore critical concepts including exons, introns, and their roles in genetic expression. Perfect for preparing for exams or enhancing your knowledge of molecular biology.
