Chapter 17

A particular triplet of bases in the coding sequence of DNA is 5'-AAA-3'. The anticodon on the tRNA that binds the mRNA codon is ________.

3′-AAA-5′

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.

During the elongation phase of translation, which site in the ribosome represents the first location where a codon pairs with an anticodon?

A site

Which of the following processes will occur at the exposed 3′ end of a tRNA molecule?

An amino acid will bind covalently

Which of the following is NOT a modification made to eukaryotic mRNA before it is exported to the cytosol?

Exons are removed.

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.

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 that accomplishes this task in eukaryotes?

Messenger RNA is transcribed from a single gene and transfers information to the cytoplasm, where protein synthesis takes place.

Which of the following best describes the redundancy in the genetic code?

More than one codon can specify the addition of the same amino acid.

Which of the following characteristics of gene expression is shared by eukaryotic and prokaryotic cells?

Signal sequences are needed for the production of membrane proteins.

Which of the following best explains the observation that in bacteria, there are 61 mRNA codons that specify an amino acid, but only 45 tRNAs?

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 RNA or polypeptide product

What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure?

hydrogen bonding between base pairs

In the structure of many eukaryotic genes, individual exons parallel which of the following?

the various domains of the protein product

Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase?

transcription factors

The nontemplate (coding) strand of a portion of a gene reads 5′-TTCACTGGTTCA-3′. What is the sequence of the resulting transcript (mRNA) for this portion?

′-UUCACUGGUUCA-3′

Translation termination occurs when a ribosome interacts with which of the following structures?

a stop codon

Which of the following molecular structures contains codons?

mRNA

In eukaryotes which of the following is the first step in translation?

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

Which of the following terms does not directly pertain to translation?

DNA

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 describes the effect of a nonsense mutation 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 molecules carries information from DNA and directs incorporation of amino acids at the ribosome?

mRNA

Which of the following molecules directly participates in the process of translation?

mRNA, tRNA, and rRNA

Which component is directly involved in translation?

ribosome

Which of the following structures is needed for the translation initiation complex to form in eukaryotes?

5′ cap

Which of the following is the best example of gene expression?

Mouse fur color results from pigment formed by gene-encoded enzymes.

The anticodon of a particular tRNA molecule is ________.

complementary to the corresponding mRNA codon

Jennifer Doudna discovered CRISPR-Cas9 due to its role in which of the following?

defending bacteria against bacteriophage infection

Which of the following processes occurs in prokaryotes but not in eukaryotes?

simultaneous transcription and translation of the same mRNA

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′

Use this model of a eukaryotic primary transcript to answer the following question.E = exon and I = intron5′-UTR E1 I1 E2 I2 E3 I3 E4 UTR-3′If the primary transcript is processed and transported to the cytosol, which of the following molecules best represents the mRNA that will be produced?

5′-UTR E1 E2 E3 E4 UTR-3′

Which of the following is true of a codon?

It can be either in DNA or in RNA.

Which of the following characteristics allows the CRISPR Cas9 enzyme to be an effective way to generate mutations that block the function of a specific protein (knock out)?

It's function is regulated by a complementary guide RNA.

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.

According to the central dogma, which of the following intermediate molecules correctly completes the flow chart describing the flow of information in a cell blank? DNA → ________ → Proteins

MRNA

Which answer correctly compares prokaryotic and eukaryotic codons?

Organisms utilize codons that are nearly universal among all organisms.

Which of the following processes occurs as part of transcription?

RNA is synthesized

In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a protein?

RNA polymerase II

Which of the following statements comparing prokaryotic and eukaryotic transcription is not true?

RNA polymerase requires a primer in bacteria; in eukaryotes, it does not.

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 of the following statements about RNA processing is correct?

Ribozymes may function in RNA splicing.

Two mRNAs (mRNA X and mRNA Y) are synthesized with the same exon sequences but poly-A tails of very different lengths. mRNA X is 7,500 bases long. mRNA Y is 6,900 bases long. The mRNA's are added to separate in vitro translation mixtures containing radioactive methionine and the reactions are allowed to proceed for 30 minutes. When the mixtures are analyzed which of the following outcomes will most likely occur?

The mRNA X mixture will contain more radioactive proteins than the mRNA Y mixture.

Which of the following is most likely to occur if a researcher removes the 5′ cap and poly-A tail of an mRNA and inserts the mRNA molecule into a eukaryotic cell?

The molecule will be degraded by enzymes.

Which of the following changes in an exon is most likely to result in a nonfunctional protein product?

a base-pair deletion

A single base substitution mutation is likely to have a less harmful effect when the base change results in which of the following?

a codon that specifies the same amino acid as the original codon

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 translation of mRNA into the primary structure of a polypeptide depends on specificity in the ________.

attachment of amino acids to tRNAs

RNA is single stranded, can hydrogen-bond with other nucleic acids, and has functional groups that can function in catalysis. These characteristics support that RNA could have which of the following cellular roles?

forming peptide bonds

Which of the following is true of RNA processing?

nucleotides are added at both ends of the RNA

Which of the following is not a normal feature of prokaryotic mRNA?

poly-A tail

What kind of molecules can be transcription factors?

proteins

In eukaryotic cells, transcription cannot begin until ________.

several transcription factors have bound to the promoter

When a mutation caused by a nucleotide-pair insertion occurs in a protein-coding region, which of the following types of mutations cannot occur?

silent

Which answer correctly compares the primary transcript in the nucleus of a eukaryotic cell with the functional mRNA?

the primary transcript is larger than the mRNA

Which answer correctly compares the primary transcript in a prokaryotic cell with the functional mRNA?

the primary transcript is the same size as the mRNA