AP Biology - Chapter 17: From Gene to Protein

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Which of the following is not true of RNA processing? A) Exons are cut out before mRNA leaves the nucleus. B) Nucleotides may be added at both ends of the RNA. C) Ribozymes may function in RNA splicing. D) RNA splicing can be catalyzed by spliceosomes. E) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.

A) Exons are cut out before mRNA leaves the nucleus.

The anticodon of a particular tRNA molecule is A) complementary to the corresponding mRNA codon. B) complementary to the corresponding triplet in rRNA. C) the part of tRNA that bonds to a specific amino acid. D) changeable, depending on the amino acid that attaches to the tRNA. E) catalytic, making the tRNA a ribozyme.

A) complementary to the corresponding mRNA codon.

Which component is not directly involved in translation? A) mRNA B) DNA C) tRNA D) ribosomes E) GTP

B) DNA

What is the effect of a nonsense mutation in a gene? A) It changes an amino acid in the encoded protein. B) It has no effect on the amino acid sequence of the encoded protein. C) It introduces a premature stop codon into the mRNA. D) It alters the reading frame of the mRNA. E) It prevents introns from being excised.

C) It introduces a premature stop codon into the mRNA.

An experimenter has altered the 3ʹ end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3ʹ AC. Which of the following hypotheses describes the most likely result? A) tRNA will not form a cloverleaf. B) The nearby stem end will pair improperly. C) The amino acid methionine will not bind. D) The anticodon will not bind with the mRNA codon. E) The aminoacylsynthetase will not be formed.

C) The amino acid methionine will not bind.

Of the following, which is the most current description of a gene? A) a unit of heredity that causes formation of a phenotypic characteristic B) a DNA subunit that codes for a single complete protein C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide D) a DNA—RNA sequence combination that results in an enzymatic product E) a discrete unit of hereditary information that consists of a sequence of amino acids

C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

When a tRNA molecule is shown twisted into an L shape, the form represented is A) its linear sequence. B) its 2-dimensional shape. C) its 3-dimensional shape. D) its microscopic image

C) its 3-dimensional shape.

Where does tRNA #2 move to after this bonding of lysine to the polypeptide? A) A site B) P site C) E site D) Exit tunnel E) Directly to the cytosol

D) Exit tunnel

Which of the following is not true of a codon? A) It consists of three nucleotides. B) It may code for the same amino acid as another codon. C) It never codes for more than one amino acid. D) It extends from one end of a tRNA molecule. E) It is the basic unit of the genetic code.

D) It extends from one end of a tRNA molecule.

Which component of the complex described enters the exit tunnel through the large subunit of the ribosome? A) tRNA with attached lysine (#1) B) tRNA with polypeptide (#2) C) tRNA that no longer has attached amino acid D) newly formed polypeptide E) initiation and elongation factors

D) newly formed polypeptide

Which of the following DNA mutations is the most likely to be damaging to the protein it specifies? A) a base-pair deletion B) a codon substitution C) a substitution in the last base of a codon D) a codon deletion E) a point mutation

A) a base-pair deletion

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate? A) an assembled ribosome with a polypeptide attached to the tRNA in the P site B) separated ribosomal subunits, a polypeptide, and free tRNA C) an assembled ribosome with a separated polypeptide D) separated ribosomal subunits with a polypeptide attached to the tRNA E) a cell with fewer ribosomes

A) an assembled ribosome with a polypeptide attached to the tRNA in the P site

Garrod hypothesized that ʺinborn errors of metabolismʺ such as alkaptonuria occur because A) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. B) enzymes are made of DNA, and affected individuals lack DNA polymerase. C) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA. D) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors. E) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.

A) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Sickle-cell disease is probably the result of which kind of mutation? A) point B) frameshift C) nonsense D) nondisjunction E) both B and D

A) point

Which of the following statements are true about protein synthesis in prokaryotes? A) Extensive RNA processing is required before prokaryotic transcripts can be translated. B) Translation can begin while transcription is still in progress. C) Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles. D) Translation requires antibiotic activity. E) Unlike eukaryotes, prokaryotes require no initiation or elongation factors.

B) Translation can begin while transcription is still in progress.

Which point mutation would be most likely to have a catastrophic effect on the functioning of a protein? A) a base substitution B) a base deletion near the start of a gene C) a base deletion near the end of the coding sequence, but not in the terminator codon D) deletion of three bases near the start of the coding sequence, but not in the initiator codon E) a base insertion near the end of the coding sequence, but not in the terminator codon

B) a base deletion near the start of a gene

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) a deletion of a codon B) a deletion of 2 nucleotides C) a substitution of the third nucleotide in an ACC codon D) a substitution of the first nucleotide of a GGG codon E) an insertion of a codon

B) a deletion of 2 nucleotides

When does translation begin in prokaryotic cells? A) after a transcription initiation complex has been formed B) as soon as transcription has begun C) after the 5ʹ caps are converted to mRNA D) once the pre-mRNA has been converted to mRNA E) as soon as the DNA introns are removed from the templat

B) as soon as transcription has begun

The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following? A) polypeptide factors plus ATP B) polypeptide factors plus GTP C) polymerases plus GTP D) SRP plus chaperones E) signal peptides plus release factor

B) polypeptide factors plus GTP

In eukaryotic cells, transcription cannot begin until A) the two DNA strands have completely separated and exposed the promoter. B) several transcription factors have bound to the promoter. C) the 5ʹ caps are removed from the mRNA. D) the DNA introns are removed from the template. E) DNA nucleases have isolated the transcription unit.

B) several transcription factors have bound to the promoter.

Each of the following options is a modification of the sentence THECATATETHERAT. Which of the following is analogous to a single substitution mutation? A) THERATATETHECAT B) THETACATETHERAT C) THECATARETHERAT D) THECATATTHERAT E) CATATETHERAT

C) THECATARETHERAT

Why might a point mutation in DNA make a difference in the level of proteinʹs activity? A) It might result in a chromosomal translocation. B) It might exchange one stop codon for another stop codon. C) It might exchange one serine codon for a different serine codon. D) It might substitute an amino acid in the active site. E) It might substitute the N terminus of the polypeptide for the C terminus.

D) It might substitute an amino acid in the active site.

Each of the following options is a modification of the sentence THECATATETHERAT. Which of the following is analogous to a frameshift mutation? A) THERATATETHECAT B) THETACATETHERAT C) THECATARETHERAT D) THECATATTHERAT E) CATATETHERAT

D) THECATATTHERAT

In the 1920s Muller discovered that X-rays caused mutation in Drosophila. In a related series of experiments, in the 1940s, Charlotte Auerbach discovered that chemicalsshe used nitrogen mustardshave a similar effect. A new chemical food additive is developed by a cereal manufacturer. Why do we test for its ability to induce mutation? A) We worry that it might cause mutation in cereal grain plants. B) We want to make sure that it does not emit radiation. C) We want to be sure that it increases the rate of mutation sufficiently. D) We want to prevent any increase in mutation frequency. E) We worry about its ability to cause infection.

D) We want to prevent any increase in mutation frequency.

Which of the following mutations would be most likely to have a harmful effect on an organism? A) a base-pair substitution B) a deletion of three nucleotides near the middle of a gene C) a single nucleotide deletion in the middle of an intron D) a single nucleotide deletion near the end of the coding sequence E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence

E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Gene expression in Archaea differs from that in other prokaryotes. It shares features with which of the following? A) eubacteria only B) eukaryotes only C) protists only D) fungi only E) bacteria and eukaryotes

E) bacteria and eukaryotes

A frameshift mutation could result from A) a base insertion only. B) a base deletion only. C) a base substitution only. D) deletion of three consecutive bases. E) either an insertion or a deletion of a base.

E) either an insertion or a deletion of a base.

A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Which enzyme causes a covalent bond to attach lysine to the polypeptide? A) ATPase B) lysine synthetase C) RNA polymerase D) ligase E) peptidyl transferase

E) peptidyl transferase