Campbell Biology Chapter 17 Cards

The following question refers to this figure of a simple metabolic pathway: According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway? 0 1 2 3 It cannot be determined from the pathway.

2

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is 5' TCA 3'. 3' UGA 5'. 3' UCA 5'. 3' ACU 5'. either UCA or TCA, depending on wobble in the first base.

3' UCA 5'.

RNA polymerase moves in which direction along the DNA? 5' to 3' along whichever strand it's on 5' to 3' along the template strand 5' to 3' along the double-stranded DNA 3' to 5' along the nontemplate strand 3' to 5' along the template strand

3' to 5' along the template strand

The following question refers to this table of codons. 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? 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA 5' GGG-AAA-TTT-AAA-CCC-ACT-GGG 5' TTT-CCC-AAA-GGG-TTT-CCC 3' UUU-CCC-AAA-GGG-UUU-CCC 3' AUG-AAA-GGG-TTT-CCC-AAA-GGG

5' TTT-CCC-AAA-GGG-TTT-CCC

Which of these is currently considered the best definition of a gene? A gene codes for either a polypeptide or an RNA molecule. A gene codes for a particular ribozyme. A gene codes for a single polypeptide. A gene codes for a single protein. A gene codes for a single enzyme.

A gene codes for either a polypeptide or an RNA molecule.

Which of the following does not occur in prokaryotic gene expression, but does in eukaryotic gene expression? RNA polymerase binds to the promoter. A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end. RNA polymerase requires a primer to elongate the molecule. mRNA, tRNA, and rRNA are transcribed. Transcription can begin as soon as translation has begun even a little.

A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.

How is translation initiated? The small ribosomal subunit binds to the mRNA. The tRNA bearing methionine binds to the start codon. The large ribosomal subunit binds to the small one. The start codon signals the start of translation. All of the above.

All of the above.

A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate? The sequence evolves very rapidly. The sequence is found in many but not all promoters. Any mutation in the sequence is selected against. The sequence is transcribed at the start of every gene. The sequence does not mutate.

Any mutation in the sequence is selected against.

Which of the following provides some evidence that RNA probably evolved before DNA? DNA polymerase has proofreading function. DNA polymerase uses primer, usually made of RNA. RNA polymerase does not require localized unwinding of the DNA. RNA polymerase uses DNA as a template. RNA polymerase makes a single-stranded molecule.

DNA polymerase uses primer, usually made of RNA.

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

It introduces a premature stop codon into the mRNA.

Which of the following best describes the significance of the TATA box in eukaryotic promoters? Its significance has not yet been determined. It is the recognition site for a specific transcription factor. It prevents supercoiling of the DNA near the start site. It is the recognition site for ribosomal binding. It sets the reading frame of the mRNA.

It is the recognition site for a specific transcription factor.

Why might a point mutation in DNA make a difference in the level of a protein's activity? It might substitute the N-terminus of the polypeptide for the C-terminus. It might exchange one serine codon for a different serine codon. It might result in a chromosomal translocation. It might exchange one stop codon for another stop codon. It might substitute a different amino acid in the active site.

It might substitute a different amino acid in the active site.

Where does RNA polymerase begin transcribing a gene into mRNA? It looks for the AUG start codon. Transfer RNA acts to translate the message to RNA polymerase. It starts at one end of the chromosome. It starts after a certain nucleotide sequence called a promoter. The ribosome directs it to the correct portion of the DNA molecule.

It starts after a certain nucleotide sequence called a promoter.

What is the function of RNA polymerase? It adds nucleotides to the 5' end of the growing mRNA molecule. It unwinds the double helix and adds nucleotides to a growing strand of RNA. It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. It relies on other enzymes to unwind the double helix. All of the above.

It unwinds the double helix and adds nucleotides to a growing strand of RNA.

Which one of the following is true of tRNAs? tRNAs are double-stranded. tRNAs carry special sequences known as codons. Each tRNA binds a particular codon. There are four types of tRNA. All of the above. None of the above.

None of the above.

Which of the following statements best describes the termination of transcription in prokaryotes? Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA. RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript. RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript. RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase.

RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

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

Translation can begin while transcription is still in progress.

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is TTT. AAA. UUU. UUA. either UAA or TAA, depending on first base wobble.

UUU.

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

a base-pair deletion

What does a mutagen cause? a change in the sequence of DNA problems with mitosis decreased enzyme activity throughout the cell a reduction in the number of tRNA molecules available for protein synthesis decreased permeability of the nuclear envelope

a change in the sequence of DNA

Which of the following nucleotide triplets best represents a codon? a sequence in tRNA at the 3' end a triplet in the same reading frame as an upstream AUG a triplet separated spatially from other triplets a triplet at the opposite end of tRNA from the attachment site of the amino acid a triplet that has no corresponding amino acid

a triplet in the same reading frame as an upstream AUG

What is a ribozyme? an enzyme that uses RNA as a substrate an enzyme that catalyzes the association between the large and small ribosomal subunits an enzyme that synthesizes RNA primers during DNA replication an enzyme that synthesizes RNA as part of the transcription process an RNA with enzymatic activity

an RNA with enzymatic activity

A simple metabolic pathway is shown below. A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation? an accumulation of C and no production of A and B an accumulation of A and no production of B and C an accumulation of B and C and no production of A an accumulation of B and no production of A and C an accumulation of A and B and no production of C

an accumulation of A and no production of B and C

Use this representation to answer the following question. DNA template strand 5' ____________________________ 3' DNA complementary strand 3' ____________________________ 5' If the DNA shown corresponds to a transcription unit, where would the promoter be located? at the 3' end of the newly made RNA at/near the left end it cannot be determined at/near the right end in the middle

at/near the right end

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the binding of ribosomes to mRNA. shape of the A and P sites of ribosomes. attachment of amino acids to tRNAs. bonding of the anticodon to the codon. bonding of the anticodon to the codon and the attachment of amino acids to tRNAs.

bonding of the anticodon to the codon and the attachment of amino acids to tRNAs.

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

either an insertion or a deletion of a base.

The flow of information in a cell proceeds in what sequence? from protein to RNA to DNA from DNA to protein to RNA from RNA to protein to DNA from DNA to RNA to protein from RNA to DNA to protein

from DNA to RNA to protein

After an RNA molecule is transcribed from a eukaryotic gene, what are removed and what are spliced together to produce an mRNA molecule with a continuous coding sequence? operators ... promoters exons ... introns introns ... exons promoters ... operators silencers ... enhancers

introns ... exons

The following question refers to this table of codons. What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3' met-leu-phe-arg-glu-glu met-ser-ser-leu-ser-leu met-arg-glu-arg-glu-arg met-glu-arg-arg-glu-leu met-ser-leu-ser-leu-ser

met-ser-ser-leu-ser-leu

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? minimal medium supplemented with nutrients A and C minimal medium supplemented with nutrient A only minimal medium supplemented with nutrient B only minimal medium minimal medium supplemented with nutrient C only

minimal medium supplemented with nutrient B only

Transcription in eukaryotes requires which of the following in addition to RNA polymerase? ribosomes and tRNA start and stop codons the protein product of the promoter several transcription factors aminoacyl-tRNA synthetase

several transcription factors

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that competitive exclusion forces some tRNAs to be destroyed by nucleases. the DNA codes for all 61 tRNAs but some are then destroyed. some tRNAs have anticodons that recognize four or more different codons. the rules for base pairing between the third base of a codon and tRNA are flexible. many codons are never used, so the tRNAs that recognize them are dispensable.

the rules for base pairing between the third base of a codon and tRNA are flexible.

Which of the following is the first event to take place in translation in eukaryotes? covalent bonding between the first two amino acids elongation of the polypeptide the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA binding of the larger ribosomal subunit to smaller ribosomal subunits base pairing of activated methionine-tRNA to AUG of the messenger RNA

the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA

A codon consists of _____ bases and specifies which _____ will be inserted into the polypeptide chain. two ... nucleotide four ... fatty acid four ... amino acid three ... amino acid three ... nucleotide

three ... amino acid