Biology Chapter 17
A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?
3′-UCA-5′
Which of the following processes occurs in eukaryotic gene expression?
A cap is added to the 5′ end of the mRNA.
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true?
A gene from an organism can theoretically be expressed by any other organism.
Which of the following statements supports the one gene-one enzyme hypothesis?
A mutation in a single gene can result in a defective protein
During the elongation phase of translation, which site in the ribosome represents the location where a codon is being read?
A site
Which of the following processes occurs when termination of translation takes place?
A stop codon is reached
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is
AAA
Which one of the following structures, if missing, would usually prevent translation from starting?
AUG codon
Codons are three-base sequences in mRNA that specify the addition of a single amino acid to the growing protein chain during translation. How do eukaryotic codons and prokaryotic codons compare?
Codons are a nearly universal language among all organisms.
Which of the following statements correctly describes Archibald Garrod's hypothesis for how "inborn errors of metabolism" such as alkaptonuria occur?
Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
What is the function of the release factor during translation in eukaryotes?
It binds to the stop codon in the A site in place of a tRNA.
Which of the following processes correctly describes alternative RNA splicing?
It can allow the production of proteins of different sizes and functions from a single mRNA.
Which of the following statements correctly describes the function of a signal peptide?
It helps target a protein to the ER
Which of the following statements correctly describes the effect a nonsense mutation would have on a gene?
It introduces a premature stop codon into the mRNA.
Which of the following statements correctly describes a ribozyme?
It is an RNA with catalytic activity.
Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes?
It is the recognition site for the binding of a specific transcription factor.
Which of the following properties is associated with a protein that will be secreted from a eukaryotic cell?
Its signal sequence must target it to the ER, after which it goes to the Golgi.
Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer in eukaryotes that accomplishes this task?
Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.
The genetic code is redundant. What is meant by this statement?
More than one codon can specify the addition of the same amino acid.
How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene?
Only a single amino acid could change, because the reading frame would be unaffected
What would be the consequence of a mutation in a bacterial cell that produces a defective aminoacyl-tRNA synthetase that attaches a lysine instead of the normal phenylalanine to tRNAs with the anticodon AAA?
Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.
which of the following processes occurs during transcription?
RNA is synthesized
In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?
RNA polymerase II
Which of the following statements best describes the termination of transcription in prokaryotes?
RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.
Which one of the following statements about RNA processing is correct?
Ribozymes may function in RNA splicing.
In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after she has removed its 5′ cap and poly-A tail. Which of the following processes would you expect her to find to have occurred?
The molecule is digested by enzymes because it is not protected at the 5′ end.
In bacteria, there are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. Which of the following statements explains this fact?
The rules for base pairing between the third base of a codon and tRNA are flexible.
Which of the following statements is true about protein synthesis in prokaryotes?
Translation can begin while transcription is still in progress.
Which of the following statements is the most current description of a gene?
a DNA sequence that is expressed to form a functional product: either RNA or polypeptide
Which of the following DNA mutations is most likely to damage the protein it specifies?
a base-pair deletion
A single base substitution mutation is likely to have a less deleterious effect when the base change exhibits which of the following results?
a codon that specifies the same amino acid as the original codon
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a deletion of two nucleotides
The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation?
a polypeptide missing an amino acid
Post-translational modifications of proteins may include which of the following processes?
addition of carbohydrates to form a glycoprotein
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the
binding of the anticodon to the codon and the attachment of amino acids to tRNAs
An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this DNA strand results in the base sequence AGGCGTTACCGT. What type of mutation does this change represent?
frameshift mutation
According to the central dogma, what is the intermediate molecule involved in the flow of information in a cell that should go in the blank? DNA >______ > Proteins
mRNA
Which of the following molecular structures contain codons?
mRNA
Which of the following molecules are required for the process of translation?
mRNA, tRNA, and rRNA
Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase?
several transcription factors
How does the primary transcript in the nucleus of a eukaryotic cell compare to the functional mRNA?
the primary transcript is larger than the mRNA
How does the primary transcript in the nucleus of a prokaryotic cell compare to the functional mRNA?
the primary transcript is the same size as the mRNA
Which of the following processes is the first event to take place in translation in eukaryotes?
the small subunit of the ribosome recognizes and attaches to the 5′ cap of mRNA
Which of the following characteristics is directly related to the coding of a single amino acid during the process of translation?
the three-base sequence of mRNA
In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?
the various domains of the polypeptide product
Which of the following processes occurs in prokaryotes but not in eukaryotes?
transcription and translation occur simultaneously
Once a peptide bond has been formed between the amino acid attached to the tRNA in the P site and the amino acid associated with the tRNA in the A site, what process occurs next?
translocation