Test Your Knowledge!
Transcription Questions1. Which nucleotide base is found in RNA but not DNA?
2. Is DNA or RNA single stranded?
3. Which of the following, introns or exons, are present in the mRNA and encode for a protein?
4. What is the name of the enzymatic complex that results in the removal of large chunks from an RNA produced in eukaryotic cells?
5. Does the poly-A polymerase require a template?
6. Which of the following is NOT a problem faced during transcription?
A. Identifying the correct place to start
B. Identifying where to terminate transcription
C. Excising of a primer
D. Accessing of the DNA bases by polymerase
E. Monitoring when and how much of a gene is transcribed
7. A critical difference between RNA and DNA is
A. that each takes on a very different structure
B. that only one is made of nucleotides
C. that only one has a sugar backbone
D. that only one contains the information needed to code for a protein
E. that only one is present in the nucleus
8. Rho independent transcription is identified by the
B. presence of the Rho protein
C. poly-A tail
D. newly formed RNA taking on a unique structure
E. presence of the RNA polymerase
9. In general, why do scientists study transcription in prokaryotes instead of only studying eukaryotes?
A. Prokaryotes are more complicated and more interesting than eukaryotes.
B. The organisms are so different that knowledge from one system cannot be easily applied to the other system.
C. Scientists have transcription figured out in eukaryotes.
D. Prokaryotes often approach problems with simpler solutions that can provide important insights into more complicated solutions in eukaryotes.
E. Scientists don't study prokaryotes anymore because eukaryotes are more important.
10. Which of the following is NOT involved in the splicing reaction?
C. The spliceosome
D. Fusion of two pieces of RNA
Transcription Answers1. Uracil is the nucleotide base found in RNA but not DNA.
2. RNA is single stranded. DNA is a double helix made of two antiparallel DNA strands.
3. Exons are present in the mRNA and encode for a protein.
4. The spliceosome is the name of the enzymatic complex that results in the removal of large chunks from an RNA produced in eukaryotic cells.
5. The poly-A polymerase does not require a template. The poly-A polymerase is unique in that it catalyzes the attachment of a long string of adenines to the RNA. There is no long chain of Ts in the template strand.
6. (C) is the correct answer. In DNA replication, an RNA primer initiates the copying of the DNA strand. This primer must then be removed later and replaced with DNA. There is no primer with transcription.
7. (A) is the correct answer. Both RNA and DNA are made of nucleotides with a sugar backbone, although RNA uses the uracil base and the sugar ribose. Both can contain the information needed to code for a protein, and both are present in the nucleus. Some RNAs, such as mRNAs, are capable of leaving the nucleus to be translated.
8. (D) is the correct answer. Rho-independent transcription does not use the factor Rho, as the name suggests. Instead, the newly formed RNA takes on a structure, called a hairpin, which causes the RNA polymerase to dissociate.
9. The correct answer is (D). Understanding transcription in a simpler system can yield important insights into how transcription might work in more complicated scenarios in eukaryotes.
10. The correct answer is (E). Rho is involved in transcriptional termination.
Translation Questions1. What type of bonds connect the amino acids of a protein?
2. Which type of codons do not code for the insertion of an amino acid?
3. If a codon undergoes a mutation that turns it into a stop codon, how will the sequence of the protein be affected?
4. What type of RNA can be thought of as the adaptor RNA?
5. A wobble can best be described as
A. the generation of a mature mRNA
B. the translation of a peptide chain
C. the incorrect base pairing between the third nucleotide of a codon-anticodon pair
D. the rule for nucleotide base pairing
E. the process by which proteins are created
6. Scientists are studying a protein linked to a disease state. They find that the disease protein contains the same sequence of amino acids as the protein in healthy individuals. Which of the following explanations does not offer a reasonable biological explanation for the disease state?
A. The amounts of the proteins are different because they are expressed differently.
B. A post-translational modification is missing on the disease protein.
C. The disease protein does not fold correctly.
D. The RNA polymerase does not read the codon code correctly on the mRNA.
E. The protein is not properly regulated.
7. Which of the following best describes how a tRNA interacts with an mRNA molecule?
A. Through complementary base pairing
B. Through protein association
C. Through covalent bond formation to the mRNA molecule
D. Through a bond to the DNA molecule
E. Through the ribosome
8. Which of the following codons signals the initiation of translation and determines the reading frame?
9. Which of the following best describes translation?
A. The creation of a RNA molecule from a DNA template
B. The creation of a peptide chain using an RNA template
C. The creation of a DNA molecule from an RNA template
D. The generation of a mature mRNA
E. The process by which an RNA is spliced and capped
Translation Answers1. The peptide bond connects the amino acids of a protein.
2. Stop codons do not code for the insertion of an amino acid.
3. If a codon undergoes a mutation that turns it into a stop codon, the sequence of the protein will be truncated.
4. The tRNA can be thought of as the adaptor RNA because it connects the mRNA to the amino acids such that a protein can be produced.
5. The correct answer is (C). A wobble specifically refers to the pairing of the third nucleotides of a codon. This pairing goes against the traditional rules of base pairing, namely that A pairs with T (or U), and G pairs with C.
6. The correct answer is (D). All that the question tells you is that the sequence of the protein is correct in the diseased individual. It could have incorrect (or a lack of) post-translational modifications, be folded incorrectly, be present at reduced or increased levels, or be expressed at the wrong time.
7. The correct answer is (A). The tRNA has a region that carries the complete reverse complement to the codon on the RNA. This three-nucleotide sequence is called the anticodon.
8. The correct answer is (E). AUG is called the start codon, and it codes for the amino acid methionine.
9. The correct answer is (B). Transcription produces an RNA molecule from a DNA template. Translation produces a polypeptide chain from a mRNA.