NAIMMCQ: From Gene to Protein

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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.

1) 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

Answer: C

2) 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

Answer: D

The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide polymer.

1) You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. How many artificial mRNA 3 nucleotide codons would be possible?

A) 3
B) 4
C) 8
D) 16
E) 64

Answer: C

2) You add polynucleotide phosphorylase to a solution of ATP, GTP, and UTP. How many artificial mRNA 3 nucleotide codons would be possible?

A) 3
B) 6
C) 9
D) 27
E) 81

Answer: D

Which of the following mutations would be most likely to have a harmful effect on an organism?

A) a nucleotide-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

Answer: E

Which component is not directly involved in translation?

A) mRNA
B) DNA
C) tRNA
D) ribosomes
E) GTP

Answer: B

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.

Answer: A

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.

Answer: A

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.

Answer: D

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 5' caps are removed from the mRNA.
D) the DNA introns are removed from the template.
E) DNA nucleases have isolated the transcription unit.

Answer: B

A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

A) 3' UUU-CCC-AAA-GGG-UUU-CCC
B) 3' AUG-AAA-GGG-TTT-CCC-AAA-GGG
C) 5' TTT-CCC-AAA-GGG-TTT-CCC
D) 5' GGG-AAA-TTT-AAA-CCC-ACT-GGG
E) 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA

Answer: C

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

What amino acid sequence will be generated, based on the following mRNA codon sequence?

5' AUG-UCU-UCG-UUA-UCC-UUG 3'

A) met-arg-glu-arg-glu-arg
B) met-glu-arg-arg-glu-leu
C) met-ser-leu-ser-leu-ser
D) met-ser-ser-leu-ser-leu
E) met-leu-phe-arg-glu-glu

Answer: D

A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be

A) 5' TTG-CTA-CAG-TAG 3'.
B) 3' AAC-GAC-GUC-AUA 5'.
C) 5' AUG-CTG-CAG-TAT 3'.
D) 3' AAA-AAT-ATA-ACA 5'.
E) 3' AAA-GAA-TAA-CAA 5'.

Answer: E

If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be capable of growing on which of the following media?

A) minimal medium
B) minimal medium supplemented with A only
C) minimal medium supplemented with B only
D) minimal medium supplemented with C only
E) minimal medium supplemented with nutrients A and B

Answer: D

If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?

If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?

A) minimal medium
B) minimal medium supplemented with nutrient A only
C) minimal medium supplemented with nutrient B only
D) minimal medium supplemented with nutrient C only
E) minimal medium supplemented with nutrients A and C

Answer: C

A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

A) an accumulation of A and no production of B and C
B) an accumulation of A and B and no production of C
C) an accumulation of B and no production of A and C
D) an accumulation of B and C and no production of A
E) an accumulation of C and no production of A and B

Answer: A

According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

A) 0
B) 1
C) 2
D) 3
E) It cannot be determined from the pathway.

Answer: C

When the genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?

A) There are 20,000 genes.
B) Each gene codes for one protein.
C) Any other regions are "junk" DNA.
D) There are also genes for RNAs other than mRNA.
E) The species is highly evolved.

Answer: D

In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene?

A) the introns
B) eukaryotic polymerases
C) a bacterial promoter sequence
D) eukaryotic ribosomal subunits
E) eukaryotic tRNAs

Answer: C

In comparing DNA replication with RNA transcription in the same cell, which of the following is true only of replication?

A) It uses RNA polymerase.
B) It makes a new molecule from its 5' end to its 3' end.
C) The process is extremely fast once it is initiated.
D) The process occurs in the nucleus of a eukaryotic cell.
E) The entire template molecule is represented in the product.

Answer: E

Which of the following is true of transcription in domain Archaea?

A) It is regulated in the same way as in domain Bacteria.
B) There is only one kind of RNA polymerase.
C) It is roughly simultaneous with translation.
D) Promoters are identical to those in domain Eukarya.
E) It terminates in a manner similar to bacteria.

Answer: C

Gene expression in the domain Archaea in part resembles that of bacteria and in part that of the domain Eukarya. In which way is it most like the domain Eukarya?

A) Domain Archaea have numerous transcription factors.
B) Initiation of translation is like that of domain Eukarya.
C) There is only one RNA polymerase.
D) Transcription termination often involves attenuation.
E) Post-transcriptional splicing is like that of Eukarya.

Answer: A