Gene Expression I: Transcription And Related Stuff
The molecular biology of transcription.
Questions and Answers
- 1.
RNA polymerase's job is:
- A.
9-5
- B.
Part time
- C.
Weekends only
- D.
Second shift
- E.
Transcription
Correct Answer
E. TranscriptionExplanation
RNA polymerase's job is transcription. Transcription is the process by which RNA polymerase synthesizes RNA using a DNA template. It reads the DNA sequence and produces a complementary RNA molecule. This RNA molecule can then be used to make proteins or perform other functions in the cell. Therefore, the correct answer is transcription.Rate this question:
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- 2.
E. coli's RNA polymerase core enzyme does NOT include the subunit called _______.
Correct Answer
σ
sigmaExplanation
E. coli's RNA polymerase core enzyme does not include the subunit called sigma (σ). Sigma is a separate subunit that associates with the core enzyme to form the holoenzyme. The sigma subunit is responsible for recognizing the promoter region on the DNA and initiating transcription by guiding the core enzyme to the correct starting point. Without the sigma subunit, the core enzyme would not be able to efficiently initiate transcription.Rate this question:
- 3.
The σ (sigma) subunit of E. coli's RNA polymerase is responsible for RNA polymerase binding to the site on the DNA called the _______.
Correct Answer
promoterExplanation
The σ (sigma) subunit of E. coli's RNA polymerase is responsible for RNA polymerase binding to the site on the DNA called the promoter. The promoter is a specific sequence of DNA that signals the beginning of a gene and provides the binding site for RNA polymerase. The σ subunit recognizes and binds to the promoter sequence, allowing RNA polymerase to initiate transcription and begin synthesizing RNA from the DNA template. This interaction between the σ subunit and the promoter is crucial for the proper regulation of gene expression in E. coli.Rate this question:
- 4.
In eukaryotes, there are several RNA polymerases and the one that makes pre-mRNA is RNA polymerase _______. (We didn't cover this one this year, 2010).
Correct Answer
II
2Explanation
In eukaryotes, there are multiple types of RNA polymerases responsible for transcribing different types of RNA molecules. The RNA polymerase that synthesizes pre-mRNA is known as RNA polymerase II. This enzyme is responsible for transcribing protein-coding genes, and it is essential for gene expression and the production of mature mRNA molecules. Therefore, the correct answer to the question is II,2.Rate this question:
- 5.
In eukaryotes, proteins other than RNA polymerase are needed for transcription to occur. Some of these are needed for the transcription of any gene and are called _______ transcription factors. (We didn't cover this one this year, 2010).
Correct Answer
generalized
generalExplanation
In eukaryotes, proteins other than RNA polymerase are required for transcription to take place. These proteins, known as transcription factors, are necessary for the transcription of any gene. They play a crucial role in regulating gene expression and ensuring the correct initiation and progression of transcription. The terms "generalized" and "general" both accurately describe these transcription factors, as they are involved in the transcription of all genes rather than being specific to a particular gene or set of genes.Rate this question:
- 6.
In eukaryotes, proteins other than RNA polymerase are needed for transcription to occur. Some of these are needed for the transcription of specific genes and are called _______ transcription factors. (We didn't cover this one this year, 2010).
Correct Answer
gene-specific
gene specific
specificExplanation
In eukaryotes, proteins other than RNA polymerase are required for transcription to take place. These proteins are known as transcription factors. Among these transcription factors, there are some that are specifically needed for the transcription of certain genes. These factors are referred to as gene-specific transcription factors.Rate this question:
- 7.
In eukaryotes, _______ makes the larger rRNAs. (be specific) (We didn't cover this one this year, 2010).
Correct Answer
RNA polymerase I
RNA polymerase 1Explanation
RNA polymerase I, also known as RNA polymerase 1, is responsible for making the larger rRNAs in eukaryotes. These larger rRNAs are essential components of the ribosomes, which are responsible for protein synthesis. RNA polymerase I specifically transcribes the genes that encode for the 18S, 5.8S, and 28S rRNAs. This enzyme is distinct from RNA polymerase II and RNA polymerase III, which transcribe other types of RNA molecules in eukaryotic cells.Rate this question:
- 8.
In eukaryotes, _______ makes the smallest rRNAs and the tRNAs. (be specific) (We didn't cover this one this year, 2010).
Correct Answer
RNA polymerase III
RNA polymerase 3Explanation
RNA polymerase III is responsible for transcribing genes that code for the smallest rRNAs and tRNAs in eukaryotes. It is one of the three types of RNA polymerases found in eukaryotic cells, each with specific functions. RNA polymerase III is specialized in transcribing small non-coding RNAs, such as transfer RNAs (tRNAs) and the smallest ribosomal RNAs (rRNAs). These molecules play crucial roles in protein synthesis and are essential for cellular function. RNA polymerase 3 is not a correct term and does not exist.Rate this question:
- 9.
In eukaryotes, the large 45S pre-rRNA molecule is cleaved and produces the ____S rRNA, the 18S rRNA, and the 5.8S rRNA. (We didn't cover this one this year, 2010).
Correct Answer
28
28SExplanation
In eukaryotes, the large 45S pre-rRNA molecule undergoes cleavage to produce the 18S rRNA, the 5.8S rRNA, and the 28S rRNA.Rate this question:
- 10.
In eukaryotes, after about 20-30 nucleotides of the pre-mRNA have been synthesized, a(n) _______ is added to the 5' end of the pre-mRNA.
Correct Answer
7-methylguanosine cap
7 methylguanosine cap
methylguanosine cap
capExplanation
In eukaryotes, a 7-methylguanosine cap is added to the 5' end of the pre-mRNA after about 20-30 nucleotides have been synthesized. This cap is important for various processes such as mRNA stability, mRNA export from the nucleus to the cytoplasm, and translation initiation. The cap also protects the mRNA from degradation and helps in the recognition of the mRNA by the ribosome during translation.Rate this question:
- 11.
The process of adding about 200 A ribonucleotides onto the 3' end of the pre-mRNA is called ________.
Correct Answer
polyadenylationExplanation
Polyadenylation is the process of adding a string of about 200 A ribonucleotides to the 3' end of the pre-mRNA molecule. This modification is important for the stability and processing of the mRNA molecule. The addition of the poly(A) tail helps protect the mRNA from degradation and allows it to be recognized and transported out of the nucleus for translation into protein. Therefore, the correct answer to the question is polyadenylation.Rate this question:
- 12.
_______ of the pre-mRNA stimulates the process of transcription termination. (We didn't cover this one this year, 2010).
Correct Answer
polyadenylation
PolyadenylationExplanation
Polyadenylation is the process of adding a string of adenine nucleotides, called a poly(A) tail, to the end of a pre-mRNA molecule. This modification is important for the stability and transport of the mRNA molecule, as well as for the efficient termination of transcription. The poly(A) tail acts as a signal for the termination machinery to recognize and stop transcription. Therefore, polyadenylation stimulates the process of transcription termination.Rate this question:
- 13.
Splicing removes segments called _______ from the pre-mRNA.
Correct Answer
introns
intronExplanation
Splicing is a process in which segments called "introns" are removed from the pre-mRNA. These introns are non-coding regions of the DNA that do not contain instructions for protein synthesis. After splicing, the remaining segments called "exons" are joined together to form the mature mRNA, which can then be translated into proteins. Therefore, both "introns" and "intron" are correct answers as they refer to the segments that are removed during splicing.Rate this question:
- 14.
As a result of splicing, two segments called _______, which are located on opposite sides of an intron, are joined together.
Correct Answer
exons
exonExplanation
Splicing is a process in molecular biology where introns (non-coding regions) are removed from pre-mRNA and exons (coding regions) are joined together to form the final mRNA molecule. In this case, the question is asking for the segments that are joined together on opposite sides of an intron. The correct answer is "exons" because multiple exons are joined together during splicing. The singular form "exon" is also correct, as it refers to a single coding segment.Rate this question:
- 15.
The photo at the top is evidence for the process of _______.
Correct Answer
splicingExplanation
The photo at the top is evidence for the process of splicing.Rate this question:
- 16.
RNA processing includes two processes: __________ and __________ (type in both words separated by a space, either order).
Correct Answer
polyadenylation capping
capping polyadenylationExplanation
RNA processing includes two processes: polyadenylation and capping. Polyadenylation refers to the addition of a poly(A) tail to the 3' end of the mRNA molecule, which helps in stabilizing the mRNA and regulating its translation. Capping, on the other hand, involves the addition of a modified guanine nucleotide to the 5' end of the mRNA, which protects it from degradation and assists in the initiation of translation. Both polyadenylation and capping are essential steps in the maturation of mRNA molecules before they can be transported out of the nucleus and translated into protein.Rate this question:
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