Title: DNA Transcription and Translation
Course: Question Banks

Q: Identify the three phases of transcription.
- promotion, elongation, termination (Incorrect. While transcription starts at a “promoter,” the first step is not called promotion.)
- elongation, methylation, termination (Incorrect. Methylation is something that happens to amino acids after a protein is made.)
- initiation, elongation, termination (Correct. Transcription starts with ‘initiation, proceeds as the transcript is “elongated,” and “terminates” when a stop sequence)
A: initiation, elongation, termination

Q: ________ takes place in the nucleus.
- Translation (Incorrect. Translation occurs in the cytoplasm.)
- Respiration (Incorrect. Respiration, at least cellular respiration, occurs in mitochondria.)
- Transcription (Correct. Transcription occurs in the nucleus; DNA never leaves the nucleus.)
A: Transcription

Q: The ________ is made from the DNA template by using complementary base pairing rules and will become functional proteins.
- tRNA strand (Incorrect. The tRNA strand does not become functional proteins.)
- rRNA strand (Incorrect. The rRNA becomes part of the ribosome.)
- mRNA strand (Correct. Just like with DNA replication, an mRNA strand is made from the DNA template using complementary base pairing rules.)
A: mRNA strand

Q: RNA transcription begins at a ________.
- starter (Incorrect. RNA transcription does not begin with a starter.)
- trigger (Incorrect. RNA transcription does not begin with a trigger.)
- promoter (Correct. RNA transcription begins at a promoter region on the DNA template.)
A: promoter

Q: What is the first mRNA processing step?
- splicing (Incorrect. Splicing is actually the last mRNA processing step.)
- 3′ poly-A tail addition (Incorrect. The poly-A tail cannot be added until the transcript is complete.)
- 5′ capping (Correct. The 5′ cap is actually added before transcription even completes.)
A: 5′ capping

Q: ________ protect(s) the pre-mRNA molecule.
- The 5′ tail (Incorrect. There is not tail on the 5&prime end.)
- Exons (Incorrect. Exons are part of the pre-mRNA, but do not protect it.)
- The 3′ poly-A tail (Correct. The poly-A tail protects the pre-mRNA molecule from degradation.)
A: The 3′ poly-A tail

Q: The process of pre-mRNA splicing removes ________.
- exons (Incorrect. Exons are the ‘coding’ portion of the transcript: they are the sequence that will be translated into a protein product.)
- regulatory sequences (Incorrect. While some of the removed sequences may play a regulatory role, it is not known that they do.)
- introns (Correct. Splicing cuts out the introns and splices together the exons into a coding mRNA.)
A: introns

Q: Ribosomes contain catalytic ________ molecules.
- mRNA (Incorrect. mRNA is not part of a ribosome.)
- tRNA (Incorrect. tRNA is not part of a ribosome.)
- rRNA (Correct. rRNA is a catalytic RNA molecule that forms the ribosome complex along with several proteins.)
A: rRNA

Q: The small subunit of a ________ binds the template to be translated.
- codon (Incorrect. There is no small (or large) subunit to a codon.)
- protein (Incorrect. No protein subunits directly bind the translation template.)
- ribosome (Correct. The small subunit of a ribosome binds the mRNA template.)
A: ribosome

Q: The ________ molecules actually translate RNA into proteins.
- mRNA (Incorrect. mRNA is the template for the protein, not the translator.)
- rRNA (Incorrect. rRNA is a catalytic RNA molecule that forms the ribosome complex along with several proteins. But it is not the actual translator.)
- tRNA (Correct. tRNA binds to the mRNA template and adds the appropriate amino acid to the growing polypeptide chain. Therefore, it is the actual translator.)
A: tRNA

Q: A given amino acid could be encoded by more than one nucleotide triplet. This indicates that the genetic code is ________.
- flexible (Incorrect. We do not call the genetic code flexible.)
- multimodal (Incorrect. We do not call the genetic code multimodal.)
- degenerate (Correct. The code is degenerate because there are some amino acids encoded for by more than one codon.)
A: degenerate

Q: Amino acids are encoded by a ________ codon.
- single nucleotide (Incorrect. There are only four nucleotides but 20 amino acids. This math does not work.)
- nucleotide doublet (Incorrect. This math does not work as a nucleotide doublet only generates 16 unique combinations. There are 20 amino acids.)
- nucleotide triplet (Correct. Using a triplet code there are 64 unique combinations. In this fashion the code adequately covers the 20 amino acids while also having some degeneracy (multiple codons for one amino acid).)
A: nucleotide triplet

Q: There are ________ stop (nonsense) codons.
- five (Incorrect. There are not this many stop codons.)
- four (Incorrect. There are not this many stop codons.)
- three (Correct. UAA, UAG, and UGA are the three nonsense codons.)
A: three

Q: Identify the three phases of translation.
- Promotion, elongation, and termination (Incorrect. These are not the phases of translation.)
- Promotion, termination, and methylation (Incorrect. These are not the phases of translation.)
- Initiation, elongation, and termination (Correct. Translation proceeds from initiation through elongation to termination.)
A: Initiation, elongation, and termination

Q: When the A site encounters a ________ codon, translation ends.
- missense (Incorrect. There are no missense codons.)
- termination (Incorrect. Even though translations stops, or terminates, upon encountering one of these codons, this is not the terminology used.)
- nonsense (Correct. “Stop” codons are called nonsense codons.)
A: nonsense

Q: Translation always begins by adding a(n) ________ to the beginning of every polypeptide chain.
- GTP (Incorrect. GTP powers the process of translation; it is not part of the polypeptide chain.)
- AUG (Incorrect. This is the codon sequence that encodes for the start of the polypeptide chain, but it is not in the polypeptide chain.)
- methionine (Correct. Methionine is the starting amino acid in every polypeptide chain.)
A: methionine

Q: According to the central dogma, ________.
- RNA may be reverse transcribed into DNA (Incorrect. Some viruses do use reverse transcription to make a DNA copy of their genome inside a host, but this isn’t because of the central dogma.)
- DNA is translated to protein (Incorrect. DNA is not translated directly into protein.)
- DNA is transcribed to RNA (Correct. DNA must be protected within the nucleus so it is transcribed into RNA which is then translated into protein.)
A: DNA is transcribed to RNA

Q: DNA is ultimately translated to proteins ________.
- continuously (Incorrect. DNA is only transcribed to RNA when that gene needs to be expressed, which would then be translated upon need.)
- Independent of proteins (Incorrect. Translation requires proteins even as it ‘builds’ them.)
- according to the central dogma (Correct. DNA must be protected within the nucleus so it is transcribed into RNA which is then translated into protein.)
A: according to the central dogma

Q: The central dogma of life applies to ________.
- prokaryotes (Incorrect. Prokaryotes are not the only organisms that live life by the central dogma.)
- eukaryotes (Incorrect. Eukaryotes are not the only organisms that live life by the central dogma.)
- both prokaryotes and eukaryotes (Correct. All organisms follow the central dogma of life: DNA is transcribed to RNA which is translated to proteins.)
A: both prokaryotes and eukaryotes

Q: Mutations will ________ be inherited.
- always (Incorrect. Mutations that occur in body cells of an adult will not be inherited.)
- never (Incorrect. Mutations that occur in germ cells before reproduction occurs could be inherited.)
- sometimes (Correct. It all depends on when and where a mutation occurs: mutations in somatic cells will not be passed on but mutations in germ cells can be.)
A: sometimes

Q: Mutations that are ________ are considered to be fixed.
- silent (Incorrect. The fact that a mutation does not cause an obvious effect does not make it fixed.)
- detrimental (Incorrect. The fact that a mutation does not cause an ill effect does not make it fixed.)
- not repaired (Correct. Mutations that are not repaired will become the ‘new’ DNA sequence and will be copied each time the mutated sequence replicates.)
A: not repaired

Q: Mutations ________.
- are always bad (Incorrect. Some mutations can cause beneficial impacts, such as conveying a resistance to malaria.)
- are usually beneficial (Incorrect. Mutations can disrupt normal gene activity and result in diseases like cancer or sickle cell anemia.)
- have variable impacts (Correct. Mutations may have a positive, negative, or neutral effect. It all depends on where the mutation is, when it occurs, and what the actual sequence change is.)
A: have variable impacts

Q: ________ mutations result from exposure to a hazard such as a chemical.
- Spontaneous (Incorrect. Spontaneous mutations have no known cause.)
- De novo (Incorrect. De novo is not the term used to describe mutations caused by environmental agents.)
- Induced (Correct. The hazardous chemical causes (induces) the mutation.)
A: Induced

Q: Silent mutations have ________.
- limited, but noticeable, effect on an organism (Incorrect. Silent mutations do not have limited effects.)
- extensive effects on an organism (Incorrect. Silent mutations do not have extensive effects.)
- no effect on an organism (Correct. Mutations with no effect on an organism are called ‘silent’.)
A: no effect on an organism

Q: The body will naturally generate ________ mutations.
- induced (Incorrect. Induced mutations arise after exposure to an environmental agent.)
- de novo (Incorrect. De novo just means a mutation is a new one; it does not indicate the cause of a mutation.)
- spontaneous (Correct. Spontaneous mutations have no known cause.)
A: spontaneous

Q: In a transversion mutation, ________.
- adenine may be replaced with a guanine. (Incorrect. This would be a transition mutation.)
- an additional guanine may be inserted before a thymine (Incorrect. This would be an insertion.)
- thymine may be replaced with a guanine (Correct. A transversion replaces a purine with a pyrimidine (or vice versa).)
A: thymine may be replaced with a guanine