Genetic Sequences, Transcription, and Translation - GRE
Card 0 of 104
Which of the following accurately describes the promoter?
Which of the following accurately describes the promoter?
The promoter is a specific segment of DNA that signals the starting point of transcription. RNA polymerase attaches to the promoter and proceeds to create the mRNA primary transcript.
DNA polymerase binds to the RNA primer to begin DNA replication. Ribosomes bind to the 5' cap on eukaryotic mRNA.
The promoter is a specific segment of DNA that signals the starting point of transcription. RNA polymerase attaches to the promoter and proceeds to create the mRNA primary transcript.
DNA polymerase binds to the RNA primer to begin DNA replication. Ribosomes bind to the 5' cap on eukaryotic mRNA.
Compare your answer with the correct one above
The lac operon is typically found in prokaryotes in order to utilize lactose in the event that glucose is absent. How does the presence of lactose affect the lac operon?
The lac operon is typically found in prokaryotes in order to utilize lactose in the event that glucose is absent. How does the presence of lactose affect the lac operon?
The lac operon is set up in a way so that the lac repressor is able to be transcribed, regardless of glucose and lactose levels. The lac repressor will then attach to the operator, which inhibits transcription. If lactose is present, it will bind to the lac repressor, and make it detach from the operator.
This process allows the operon to be transcribed in the event that glucose is absent. If glucose is absent, but lactose is not present, then the repressor will remain in place and transcription will not take place.
The lac operon is set up in a way so that the lac repressor is able to be transcribed, regardless of glucose and lactose levels. The lac repressor will then attach to the operator, which inhibits transcription. If lactose is present, it will bind to the lac repressor, and make it detach from the operator.
This process allows the operon to be transcribed in the event that glucose is absent. If glucose is absent, but lactose is not present, then the repressor will remain in place and transcription will not take place.
Compare your answer with the correct one above
Which conditions would result in the largest levels of lac operon transcription?
Which conditions would result in the largest levels of lac operon transcription?
The important thing to remember about the lac operon is that it is transcribed when glucose is absent from the cell, but lactose is present and can be utilized. As a result, the operon's transcription would be high if there are both high levels of lactose available, and very little amounts of glucose.
The important thing to remember about the lac operon is that it is transcribed when glucose is absent from the cell, but lactose is present and can be utilized. As a result, the operon's transcription would be high if there are both high levels of lactose available, and very little amounts of glucose.
Compare your answer with the correct one above
Which of the following post-transcriptional modifications occur in the nucleus?
I. 5' capping
II. Splicing
III. Polyadenylation
Which of the following post-transcriptional modifications occur in the nucleus?
I. 5' capping
II. Splicing
III. Polyadenylation
All of the post-transcriptional modifications listed occur in the nucleus. Each is important in the process of turning pre-mRNA into mature mRNA that can successfully exit the nucleus and enter into translation. These modifications allow for the appropriate recognition by ribosomes and serve to enhance the stability of the mRNA molecule.
The 5' guanosine cap is added to one end of the RNA strand, and a poly-A tail is added to the other. These modifications serve to help with ribosome recognition and prevent degradation. Spicing involves the removal of non-coding introns from the RNA transcript, allowing for translation of the proper sequence.
All of the post-transcriptional modifications listed occur in the nucleus. Each is important in the process of turning pre-mRNA into mature mRNA that can successfully exit the nucleus and enter into translation. These modifications allow for the appropriate recognition by ribosomes and serve to enhance the stability of the mRNA molecule.
The 5' guanosine cap is added to one end of the RNA strand, and a poly-A tail is added to the other. These modifications serve to help with ribosome recognition and prevent degradation. Spicing involves the removal of non-coding introns from the RNA transcript, allowing for translation of the proper sequence.
Compare your answer with the correct one above
Which of the following post-translation modifications cannot be classified as lipidation?
Which of the following post-translation modifications cannot be classified as lipidation?
Ubiquitination is the only option in which the modification to the protein does not include the binding of a lipid group to a protein. Rather, it is the addition of another peptide to the existing protein.
Ubiquitination is the only option in which the modification to the protein does not include the binding of a lipid group to a protein. Rather, it is the addition of another peptide to the existing protein.
Compare your answer with the correct one above
The process of polyadenylation results in the addition of a poly-A tail to mRNA after transcription. The poly-A tail consists of approximately 150-200 adenine bases at the 3' end of the mRNA. Which of the following best describes the purpose of polyadenylation in mRNA processing?
The process of polyadenylation results in the addition of a poly-A tail to mRNA after transcription. The poly-A tail consists of approximately 150-200 adenine bases at the 3' end of the mRNA. Which of the following best describes the purpose of polyadenylation in mRNA processing?
Polyadenylation results in a long chain of adenosine monophosphate residues being added to the 3' end of a pre-mRNA as transcription is terminating. The poly-A tail provides stability to the mRNA molecule as it is transported through the cell to its ultimate location. Without this modification, the shorter mRNA would be degraded by enzymes within the cytoplasm. The other functions listed as answers are in no part dependent on the poly-A tail.
Polyadenylation results in a long chain of adenosine monophosphate residues being added to the 3' end of a pre-mRNA as transcription is terminating. The poly-A tail provides stability to the mRNA molecule as it is transported through the cell to its ultimate location. Without this modification, the shorter mRNA would be degraded by enzymes within the cytoplasm. The other functions listed as answers are in no part dependent on the poly-A tail.
Compare your answer with the correct one above
Which of the following post-translational modifications has most typically been associated with protein degradation via activation of the cell's proteasome system?
Which of the following post-translational modifications has most typically been associated with protein degradation via activation of the cell's proteasome system?
Conjugation of ubiquitin molecules to a protein activates the ubiquitin proteasome system, which is required by cells to break down proteins into their component amino acid residues to be reallocated in protein building as necessary. While the other modifications may contribute to some degradation pathway, ubiquitin is classically considered a marker of protein destruction via the proteasome system.
Conjugation of ubiquitin molecules to a protein activates the ubiquitin proteasome system, which is required by cells to break down proteins into their component amino acid residues to be reallocated in protein building as necessary. While the other modifications may contribute to some degradation pathway, ubiquitin is classically considered a marker of protein destruction via the proteasome system.
Compare your answer with the correct one above
is the addition of a long tail of adenine bases to an mRNA during mRNA processing, and this step is crucial for the stability of the mRNA as it gets exported to other parts of the cell.
is the addition of a long tail of adenine bases to an mRNA during mRNA processing, and this step is crucial for the stability of the mRNA as it gets exported to other parts of the cell.
Polyadenylation is the process in which a "Poly-a tail," or a tail of adenine bases, is added to the 3' end of an mRNA. The other processes listed do not carry out this function.
Polyadenylation is the process in which a "Poly-a tail," or a tail of adenine bases, is added to the 3' end of an mRNA. The other processes listed do not carry out this function.
Compare your answer with the correct one above
Which conditions would result in the largest levels of lac operon transcription?
Which conditions would result in the largest levels of lac operon transcription?
The important thing to remember about the lac operon is that it is transcribed when glucose is absent from the cell, but lactose is present and can be utilized. As a result, the operon's transcription would be high if there are both high levels of lactose available, and very little amounts of glucose.
The important thing to remember about the lac operon is that it is transcribed when glucose is absent from the cell, but lactose is present and can be utilized. As a result, the operon's transcription would be high if there are both high levels of lactose available, and very little amounts of glucose.
Compare your answer with the correct one above
Which of the following accurately describes the promoter?
Which of the following accurately describes the promoter?
The promoter is a specific segment of DNA that signals the starting point of transcription. RNA polymerase attaches to the promoter and proceeds to create the mRNA primary transcript.
DNA polymerase binds to the RNA primer to begin DNA replication. Ribosomes bind to the 5' cap on eukaryotic mRNA.
The promoter is a specific segment of DNA that signals the starting point of transcription. RNA polymerase attaches to the promoter and proceeds to create the mRNA primary transcript.
DNA polymerase binds to the RNA primer to begin DNA replication. Ribosomes bind to the 5' cap on eukaryotic mRNA.
Compare your answer with the correct one above
The lac operon is typically found in prokaryotes in order to utilize lactose in the event that glucose is absent. How does the presence of lactose affect the lac operon?
The lac operon is typically found in prokaryotes in order to utilize lactose in the event that glucose is absent. How does the presence of lactose affect the lac operon?
The lac operon is set up in a way so that the lac repressor is able to be transcribed, regardless of glucose and lactose levels. The lac repressor will then attach to the operator, which inhibits transcription. If lactose is present, it will bind to the lac repressor, and make it detach from the operator.
This process allows the operon to be transcribed in the event that glucose is absent. If glucose is absent, but lactose is not present, then the repressor will remain in place and transcription will not take place.
The lac operon is set up in a way so that the lac repressor is able to be transcribed, regardless of glucose and lactose levels. The lac repressor will then attach to the operator, which inhibits transcription. If lactose is present, it will bind to the lac repressor, and make it detach from the operator.
This process allows the operon to be transcribed in the event that glucose is absent. If glucose is absent, but lactose is not present, then the repressor will remain in place and transcription will not take place.
Compare your answer with the correct one above
A protein that will be embedded in the plasma membrane is likely to be translated by .
A protein that will be embedded in the plasma membrane is likely to be translated by .
Most proteins that will be embedded in the plasma membrane are translated on ribosomes located in the rough endoplasmic reticulum. There are specific mechanisms and proteins that help insert the proteins into the membrane while they are being translated. Free-floating proteins are more likely to be translated in the cytosol. The nucleus and the Golgi do not have ribosomes used for translation, though the Golgi can play an important role in transporting proteins from the rough endoplasmic reticulum to the membrane.
Most proteins that will be embedded in the plasma membrane are translated on ribosomes located in the rough endoplasmic reticulum. There are specific mechanisms and proteins that help insert the proteins into the membrane while they are being translated. Free-floating proteins are more likely to be translated in the cytosol. The nucleus and the Golgi do not have ribosomes used for translation, though the Golgi can play an important role in transporting proteins from the rough endoplasmic reticulum to the membrane.
Compare your answer with the correct one above
Which of the following is true concerning the genetic code?
Which of the following is true concerning the genetic code?
The genetic code is unambiguous, meaning that each given codon will always code for the same amino acid. An amino acid, however, can be coded for by multiple codons, making the genetic code degenerative in nature. Once a stop codon is reached during translation, the ribosome stops making the protein.
The genetic code is unambiguous, meaning that each given codon will always code for the same amino acid. An amino acid, however, can be coded for by multiple codons, making the genetic code degenerative in nature. Once a stop codon is reached during translation, the ribosome stops making the protein.
Compare your answer with the correct one above
What site in the ribosome contains the elongating polypeptide?
What site in the ribosome contains the elongating polypeptide?
A tRNA that is attached to one amino acid will enter the ribosomal complex at the A site. It will then receive the growing polypeptide chain from the previous tRNA and move into the P site. Once handing off the chain, the tRNA that no longer has an amino acid will exit the ribosome at the E site.
The peptide chain is always anchored in the P site, where peptide bond synthesis occurs.
A tRNA that is attached to one amino acid will enter the ribosomal complex at the A site. It will then receive the growing polypeptide chain from the previous tRNA and move into the P site. Once handing off the chain, the tRNA that no longer has an amino acid will exit the ribosome at the E site.
The peptide chain is always anchored in the P site, where peptide bond synthesis occurs.
Compare your answer with the correct one above
A protein that will be embedded in the plasma membrane is likely to be translated by .
A protein that will be embedded in the plasma membrane is likely to be translated by .
Most proteins that will be embedded in the plasma membrane are translated on ribosomes located in the rough endoplasmic reticulum. There are specific mechanisms and proteins that help insert the proteins into the membrane while they are being translated. Free-floating proteins are more likely to be translated in the cytosol. The nucleus and the Golgi do not have ribosomes used for translation, though the Golgi can play an important role in transporting proteins from the rough endoplasmic reticulum to the membrane.
Most proteins that will be embedded in the plasma membrane are translated on ribosomes located in the rough endoplasmic reticulum. There are specific mechanisms and proteins that help insert the proteins into the membrane while they are being translated. Free-floating proteins are more likely to be translated in the cytosol. The nucleus and the Golgi do not have ribosomes used for translation, though the Golgi can play an important role in transporting proteins from the rough endoplasmic reticulum to the membrane.
Compare your answer with the correct one above
Which of the following is true concerning the genetic code?
Which of the following is true concerning the genetic code?
The genetic code is unambiguous, meaning that each given codon will always code for the same amino acid. An amino acid, however, can be coded for by multiple codons, making the genetic code degenerative in nature. Once a stop codon is reached during translation, the ribosome stops making the protein.
The genetic code is unambiguous, meaning that each given codon will always code for the same amino acid. An amino acid, however, can be coded for by multiple codons, making the genetic code degenerative in nature. Once a stop codon is reached during translation, the ribosome stops making the protein.
Compare your answer with the correct one above
What site in the ribosome contains the elongating polypeptide?
What site in the ribosome contains the elongating polypeptide?
A tRNA that is attached to one amino acid will enter the ribosomal complex at the A site. It will then receive the growing polypeptide chain from the previous tRNA and move into the P site. Once handing off the chain, the tRNA that no longer has an amino acid will exit the ribosome at the E site.
The peptide chain is always anchored in the P site, where peptide bond synthesis occurs.
A tRNA that is attached to one amino acid will enter the ribosomal complex at the A site. It will then receive the growing polypeptide chain from the previous tRNA and move into the P site. Once handing off the chain, the tRNA that no longer has an amino acid will exit the ribosome at the E site.
The peptide chain is always anchored in the P site, where peptide bond synthesis occurs.
Compare your answer with the correct one above
Consider the following scenario:
Gene-Z is a transcription factor required for transcribing the genes that contribute to populating the motor cortex with the proper number of neurons. Mutant mice for Gene-Z have 50% fewer motor neurons than controls (non-mutants). You genetically engineer a transgenic DNA construct that acts as a dominant negativeto Gene-Z.
You transfect an embryonic mouse brain with this dominant negative and measure that all motor neurons get and expressed this construct. What would you expect the number of neurons in the transfected brain to be if the dominant negative works with 100% efficacy, and a normal motor cortex has 100,000 cells in the region you are examining?
Consider the following scenario:
Gene-Z is a transcription factor required for transcribing the genes that contribute to populating the motor cortex with the proper number of neurons. Mutant mice for Gene-Z have 50% fewer motor neurons than controls (non-mutants). You genetically engineer a transgenic DNA construct that acts as a dominant negativeto Gene-Z.
You transfect an embryonic mouse brain with this dominant negative and measure that all motor neurons get and expressed this construct. What would you expect the number of neurons in the transfected brain to be if the dominant negative works with 100% efficacy, and a normal motor cortex has 100,000 cells in the region you are examining?
This question requires the knowledge that a dominant negativeis expected to work in the same direction as a genetic mutant; it is a loss-of-function of the gene, by expressing a version of the gene that outcompetes the actual gene but cannot perform the proper biological process. Because we are assuming the dominant negative works perfectly, it should act just like the mutant and reduce cell number by 50%, giving us 50,000 cells.
This question requires the knowledge that a dominant negativeis expected to work in the same direction as a genetic mutant; it is a loss-of-function of the gene, by expressing a version of the gene that outcompetes the actual gene but cannot perform the proper biological process. Because we are assuming the dominant negative works perfectly, it should act just like the mutant and reduce cell number by 50%, giving us 50,000 cells.
Compare your answer with the correct one above
Which of the following statements about the function of transcription factors is not true?
Which of the following statements about the function of transcription factors is not true?
Transcription factors can be activated or deactivated by any number of processes occurring within the cell and nucleus, and this it not limited to phosphatases (which remove phosphate groups from proteins). All of the other answers accurately describe possible activity and function of transcription factors.
Transcription factors can be activated or deactivated by any number of processes occurring within the cell and nucleus, and this it not limited to phosphatases (which remove phosphate groups from proteins). All of the other answers accurately describe possible activity and function of transcription factors.
Compare your answer with the correct one above
Which of the following is true?
I. Transcription factors typically bind directly to the genes that they regulate.
II. Transcription factors can bind enhancer and promoter regions upstream of the genes they regulate.
III. In eukaryotes, transcription factors frequently associate with coactivators.
IV. Transcription factors can either upregulate or downregulate transcription of a gene.
Which of the following is true?
I. Transcription factors typically bind directly to the genes that they regulate.
II. Transcription factors can bind enhancer and promoter regions upstream of the genes they regulate.
III. In eukaryotes, transcription factors frequently associate with coactivators.
IV. Transcription factors can either upregulate or downregulate transcription of a gene.
Only the first statement in this question is false. Transcription factors typically (in fact, almost always) bind upstream of the gene to enhancer or promoter regions, and are rarely found interacting with the gene's coding region itself.
Only the first statement in this question is false. Transcription factors typically (in fact, almost always) bind upstream of the gene to enhancer or promoter regions, and are rarely found interacting with the gene's coding region itself.
Compare your answer with the correct one above