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 does RNA polymerase II make?
- rRNA (Incorrect. This is the function of RNA pol I predominantly.)
- tRNA (Incorrect. This is the function of RNA pol III.)
- mRNA (Correct. RNA pol II synthesizes all protein-coding pre-mRNA regions. These will later be spliced into mature mRNA.)
A: mRNA

Q: Where is RNA polymerase I active?
- Nucleus (Incorrect. RNA pol II and pol III are active in the nucleus.)
- Nuclear membrane (Incorrect. No type of transcription occurs in the nuclear membrane.)
- Nucleolus (Correct. RNA pol I is active in the nucleolus, where rRNA is transcribed and ribosomes assembled.)
A: Nucleolus

Q: Promoters always contain a ________.
- ATAT sequence (Incorrect. This is not the uniform sequence found in promoters. It’s a Star Wars vehicle.)
- GC-rich box (Incorrect. Many eukaryotic promoters do have a GC-rich box, but not all promoters do.)
- TATA box (Correct. Eukaryotic and prokaryotic promoters both have a TATA box, though its exact location in the promoter (and exact sequence) may vary.)
A: TATA box

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: Different mRNAs are made from the same initial pre-mRNA by ________.
- processing (Incorrect. All types of pre-RNA undergo processing. This is not the term for what generates different mRNAs from the same starting pre-mRNA.)
- modification (Incorrect. Modification is not the process that generates different mRNAs from the same starting pre-mRNA.)
- alternative splicing (Correct. Alternative splicing involves combining different exons from the same pre-mRNA to make different mRNA molecules.)
A: alternative splicing

Q: Spliced ________ differ in their exons.
- pre-RNAs (Incorrect. pre-RNAs are not spliced.)
- tRNAs (Incorrect. tRNAs are not spliced.)
- mRNAs (Correct. Alternative splicing involves combining different exons from the same pre-mRNA to make different mRNA molecules.)
A: mRNAs

Q: ________ are active in targeting mRNA molecules for degradation.
- Small regulatory RNAs (Incorrect. Not all small regulatory RNAs result in degradation of an mRNA molecule.)
- Methylation enzymes (Incorrect. Methylation is a process that occurs on amino acid residues in proteins.)
- miRNA (Correct. microRNAs (miRNAs) that match a target mRNA perfectly will trigger a protein to chop the mRNA in half, leading to its breakdown.)
A: miRNA

Q: The initiator tRNA interacts with the ________ (typically AUG) to begin translation.
- Shine-Dalgarno sequence (Incorrect. This sequence helps anchor the ribosome for translation to initiate.)
- peptidyl transferase (Incorrect. This enzyme helps form each peptide bond between amino groups during elongation.)
- start codon (Correct. Translation proceeds from initiation through elongation to termination.)
A: start codon

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: 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: tRNAs are normally ________ when not involved in active protein synthesis.
- bound to ribosomes (Incorrect. tRNAs are only bound to ribosomes during active translation.)
- attached to a membrane (Incorrect. tRNAs are never bound to membranes.)
- free in the cytoplasm (Correct. When not actively translating proteins, tRNAs are free in the cytoplasm, bound to individual amino acids.)
A: free in the cytoplasm

Q: tRNAs begin as ________ molecules that are transcribed and processed in the ________.
- pre-rRNA; nucleolus (Incorrect. No part of this answer choice is correct.)
- pre-tRNA; nucleolus (Incorrect. tRNAs are not associated with the nucleolus.)
- pre-tRNA; nucleus (Correct. Pre-tRNAs are transcribed and processed in the nucleus before being released in the cytoplasm to await translation duties.)
A: pre-tRNA; nucleus

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: Proteins are moved to their final destination in a cell by way of ________.
- destination codes (Incorrect. Proteins are not moved by destination codes.)
- tickets (Incorrect. This term isn’t used though the concept is logical (tickets indicate a destination).)
- signal sequences (Correct. Signal sequences indicates where a protein is destined in a cell.)
A: signal sequences

Q: Chaperones help proteins ________.
- move within a cell (Incorrect. This is not the role of chaperones.)
- travel between cells (Incorrect. This is not the role of chaperones.)
- fold properly (Correct. Molecular chaperones help prevent some proteins from aggregating improperly during folding.)
A: fold properly

Q: Proteins may fold incorrectly if exposed to ________.
- mRNA (Incorrect. The presence of an mRNA molecule should have no impact on folding of a polypeptide product.)
- chemical modifications (Incorrect. Many proteins will undergo chemical modification during and after translation. Often this is required for proper folding.)
- unusual environments (Correct. Abnormal conditions such as high temperatures or different pH conditions can cause a correctly translated polypeptide chain to fold incorrectly and be nonfunctional.)
A: unusual environments

Q: Prokaryotic cells utilize a ________ polymerase composed of five subunits to complete transcription.
- core enzyme (Incorrect. The core enzyme is part of the polymerase structure but does not include all five subunits.)
- RNA super pol (Incorrect. This is not the term for the complete polymerase in prokaryotes.)
- holoenzyme (Correct. The holoenzyme contains all five polypeptide subunits.)
A: holoenzyme

Q: Promoters in prokaryotes consist of ________.
- a single long TATA box (Incorrect. Prokaryotic promoters do have a TATA box but that is not all.)
- three promotion zones (Incorrect. Promoters in prokaryotes do not require three specific regions.)
- two consensus sequences (Correct. There are two consensus sequences, located at -10 and -35 regions upstream of the site of transcription initiation.)
A: two consensus sequences

Q: Elongation of the transcript in prokaryotes requires the ________.
- RNA super pol (Incorrect. This is not the term for any polymerase in prokaryotes.)
- holoenzyme (Incorrect. The holoenzyme is required for initiation but not elongation.)
- core enzyme (Correct. One subunit releases from the polymerase once initiation is complete and a smaller complex known as the core enzyme completes elongation.)
A: core enzyme

Q: In prokaryotes, the ________ anchors the 30S ribosomal subunit to the correct location on the mRNA template.
- initiation factor (Incorrect. Initiation factors are involved in starting translation in prokaryotes, but they do not anchor the small subunit.)
- N-formyl-methionine (Incorrect. This is the initiator tRNA, not what anchors the small subunit.)
- Shine-Dalgarno sequence (Correct. The Shine-Dalgarno sequence is upstream of the first AUG codon and anchors the 30S ribosomal subunit to start translation.)
A: Shine-Dalgarno sequence

Q: Bacterial ribosomes are ________ than eukaryotic ones.
- larger (Incorrect. Bacterial ribosomes are not larger than eukaryotic ones.)
- less complex (Incorrect. Ribosomes are equivalent in complexity in all organisms.)
- smaller (Correct. Bacterial ribosomes are somewhat smaller than eukaryotic ones.)
A: smaller

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: ________ serve(s) as evidence that life may have evolved before the central dogma.
- Infectious proteins (Incorrect. Infectious proteins are not evidence that life evolved before the central dogma.)
- Viroids (Incorrect. Viroids do not support the idea that life evolved before the central dogma.)
- Catalytic RNA (Correct. Ribozymes both carry the directions and perform the action, meaning they do not follow the central dogma. Scientists believe this indicates the earliest forms of life were much simpler organisms, perhaps without the three molecules central to the central dogma.)
A: Catalytic RNA

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