All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
Example Questions
Example Question #11 : Rna, Transcription, And Translation
What event is indicative of transcription initiation?
RNA polymerase binds to the promoter
Telomerase lengthens the telomeres of the DNA
The RNA strand begins to be synthesized
RNA polymerase is removed from the DNA
RNA polymerase binds to the promoter
During the initiation of transcription, RNA polymerase and a group of transcription factors bind to the promoter for a given gene. This DNA segment signals the RNA polymerase where to begin creating the RNA strand.
Example Question #2 : Help With Transcription Processes
Which of the following best describes distant regulatory sequences that influence gene expression?
Promoters
Enhancers
Exons
Introns
Transcriptional start sites
Enhancers
The correct answer is enhancer. Transcription factors and mediators bind enhancer regions of DNA and influence the transcription of distant genes by chromatin looping to the proximal promoter. Promoters are regulatory sequences, however, they are typically 2 kilobase pairs upstream of the gene for which they influence transcription. Introns and exons make up a gene and are the non-coding and coding regions of the gene, respectively. The transcriptional start site consists of the first few nucleotides that are transcribed into an mRNA sequence from a gene, usually containing the 5' untranslated region (UTR).
Example Question #11 : Transcription And Rna
When does alternative splicing occur?
Following pre-mRNA transcription in the nucleus
Following mRNA loading into ribosome
Following translation
Following mRNA polyadenylation
Following mRNA translocation to the cytosol
Following pre-mRNA transcription in the nucleus
The correct answer is following pre-mRNA transcription in the nucleus. Pre-mRNA contains introns and exons. Following transcription, splicing and alternative splicing occurs to remove introns and select exons, respectively, by the spliceosome. Following splicing, 3' poly adenylation and 5' capping occur to generate a mature mRNA transcript that will translocate to the cytosol and be translated by ribosomes.
Example Question #12 : Transcription And Rna
What element(s) do all eukaryotic promoter regions share?
Transcription factors
Enhancers that accept binding agents
All of these
A basal promoter (TATA box)
None of these
All of these
Eukaryotic promoters share basic, highly conserved structure. This area does not evolve quickly because it is extremely important in DNA transcription. These promoters (in most cases) include a basic basal promoter like a TATA box, and enhancers that bind to transcription factors.
Example Question #13 : Transcription And Rna
During transcription of a eukaryotic cell, what determines the template strand?
The base sequence of the enhancer
The location of the AUG start codon
The base sequence of the promoter
The location of the MET start codon
The base sequence of the operator
The base sequence of the promoter
The TATA box is found in the promoter region of the template strand. This TATA box serves as a signal for the initiation of translation of DNA into mRNA. The location of the promoter region and it's unique base sequence signals the start of the translation process.
Example Question #14 : Transcription And Rna
Which of the following processes is not a type of RNA processing carried out by eukaryotes?
Capping of the 5' end
Nucleotide excision repair
Polyadenylation of the 3' end
Splicing and removal of introns
Nucleotide excision repair
Processing of pre-mRNA occurs in the nucleus. After transcription, three crucial modification take place. A 7-methylguanosine molecule is added to the 5' end to form a cap. Polyadenylation is added to the 3' end to create a poly-A tail. Introns are spliced out by spliceosomes, removing the non-coding regions of the RNA. The final product after modifications is considered a mature mRNA; prior to this, the transcript is known as heteronuclear RNA (htRNA).
Nucleotide excision repair is a method of proofreading after DNA replication to reduce the frequency of mutation.
Example Question #15 : Transcription And Rna
What are exons?
Set of genes that are adjacent to one another in the genome and are coordinately controlled
Genetic information coding for an amino acid sequence that will form a functional protein
Site where repressor proteins bind
Intervening non-coding segments of DNA
Genetic information coding for an amino acid sequence that will form a functional protein
Exons contain the actual genetic information coding for protein. In contrast, introns are intervening non-coding segments of DNA. During the splicing process of pre-mRNA modification, introns are removed from the sequence. Alternative splicing patterns allow multiple exon sequences to be created from a single gene, resulting in multiple proteins.
An operon is a set of genes that are adjacent to one another in the genome and are coordinately controlled. The silencer region is a site of a gene where repressor proteins bind to regulate gene expression.
Example Question #16 : Transcription And Rna
What are snRNPs (small nuclear ribonucleic particles)?
RNA molecules that serve as the link between the nucleotide sequence of nucleic acids and the amino acid sequence of proteins
RNA protein complexes that combine with pre-mRNA and other proteins to form a spliceosome
RNA component of the ribosome, essential for protein synthesis
RNA molecules that convey genetic information from DNA to the ribosome
RNA protein complexes that combine with pre-mRNA and other proteins to form a spliceosome
snRNPs are RNA protein complexes that combine with pre-mRNA and other proteins to form a spliceosome. Spliceosomes remove introns from pre-mRNA. After final modifications, the spliced pre-mRNA is considered mature mRNA and can be exported to the cytoplasm for translation.
mRNA is an RNA molecule that conveys genetic material from DNA to the ribosome. tRNA is an RNA molecule that serves as the link between the nucleotide sequence of nucleic acids and the amino acid sequence of proteins. rRNA is the RNA component of the ribosome that is essential for protein synthesis in all living organisms.
Example Question #17 : Transcription And Rna
Which of the following is not a type of RNA?
cRNA
tRNA
mRNA
rRNA
cRNA
mRNA, tRNA, and rRNA are the most commonly recognized types of RNA, though there are several more divisions. Messenger RNA (mRNA) is the product of gene transcription and is used to carry genetic information to ribosomes for translation. Transfer RNA (tRNA) is used to transport amino acid residues to active ribosomes during translation and contains anticodon sequences to bind to mRNA. Ribosomal RNA (rRNA) forms part of the ribosomes structure.
Though cRNA is not a class of RNA molecule, complementary DNA (cDNA) is used to store and analyze genomes. cDNA is the non-coding complement to the template strand used for transcription, and can be used to analyze genetic sequences.
Example Question #5 : Help With Rna Structure And Modification
All of the follwing are types of alternative RNA splicing except __________.
skipped exon
alternative 3' splicing
dual splice site
exon reversal
exon reversal
Skipped exon, dual splice site, and alternative 3' splicing are all types of alternative RNA splicing. Exon reversal is a nonsense term, and does not represent an actual biochemical process.
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