1 Show 1) Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because _____. B) enzymes are made of DNA, and affected individuals lack DNA polymerase 2 2) A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is _____. C) 3' TCA 5' 3 3) The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following? C) The same codons in different organisms translate into different amino acids. D) Different organisms have different types of amino acids. 4 4) The figure above shows a simple metabolic pathway. According to
Beadle and Tatum's hypothesis, how many genes are necessary for this pathway? C) 3 5 5) Refer to the metabolic pathway illustrated above. 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 medium
supplemented with _____. B) nutrient B only C) nutrient C only D) nutrients A and C 6 6) Refer to the metabolic pathway illustrated above. If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be able to grow on medium supplemented with _____. B) nutrient B only C) nutrient C only D) nutrients A and C 7 10) Which of the following contradicts the one-gene, one-enzyme hypothesis? 8 11) Which of the following is directly related to a single amino acid? A) the base sequence of the tRNA D) the complementarity of DNA and RNA 9 12) In the process of transcription, _____. A) DNA is replicated D) mRNA attaches to ribosomes 10 13) Codons are part of the molecular structure of _____. A) a protein D) rRNA 11 14) What does it mean when we say the genetic code is redundant? B) The genetic code is different for different domains of organisms. 12 15) Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer in eukarotes? B) 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. D) Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place. 13 16) According to the central dogma, what molecule should go in the
blank? DNA → _____ → Proteins C) mRNA 14 17) Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare? C) The translation of codons is mediated by tRNAs in
eukaryotes, but translation requires no intermediate molecules such as tRNAs in prokaryotes. 15 18) Which of the following occurs in prokaryotes but not in eukaryotes? A) post-transcriptional splicing D) gene regulation 16 19) Which of the following statements
best describes the termination of transcription in prokaryotes? 17 20) In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein? C) RNA polymerase III D) primate 18 21) Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A) start and stop codons D) aminoacyl-tRNA synthetase 19 22) Which of the following best describes the significance of the TATA box in eukaryotic promoters? C) It is the recognition site for ribosomal binding. D) Its significance has not yet been determined. 20 23) Which of the following does not occur in prokaryotic gene expression, but does occur in eukaryotic gene expression? C) A cap is added to the 5' end of the mRNA. 21 24) A ribozyme is _____. D) an enzyme that synthesizes RNA as part of the transcription process 22 25) Alternative RNA splicing _____. C) can allow the production of similar proteins from different
RNAs 23 26) In the structural organization of many eukaryotic genes, individual exons may be related to which of the following? C) the various domains of the polypeptide product D) the number of start sites for transcription 24 27) 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 would you expect her to find? 25
29) Which one of the following statements about RNA processing is true? A) Exons are cut out before mRNA leaves the nucleus. D) A primary transcript is often much shorter than the final RNA molecule that leaves the nucleus. 26 30) A primary transcript in the nucleus of a eukaryotic cell is _____ the functional mRNA, while a primary transcript in a
prokaryotic cell is _____ the functional mRNA. C) larger than; smaller than 27 31) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is _____. C) UUU 28 32) Accuracy in the translation of mRNA into the
primary structure of a polypeptide depends on specificity in the _____. C) attachment of amino acids to rRNAs 29 33) A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal
phenylalanine. The consequence of this for the cell will be that _____. B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU D) the ribosome will skip a codon every time a UUU is encountered 30 34)
There are sixty-one mRNA codons that specify an amino acid, but only forty-five tRNAs. This is best explained by the fact that _____. C) many codons are never used, so the tRNAs that recognize them are dispensable D) the DNA codes for all sixty-one tRNAs, but some are then destroyed 31 35)
Which of the following is the first event to take place in translation in eukaryotes? A) base pairing of activated methionine-tRNA to AUG of the messenger RNA D) the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA 32 36) A signal peptide _____. B) terminates translation of messenger RNA 33 37) The release factor (RF) _____. 34 43) What must occur before a newly made polypeptide is secreted from a cell? 35 44)
Translation requires _____. 36 45) During elongation, which site in the ribosome represents the location where a codon is being read? C) A site 37 46) Once a peptide 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 occurs next? C) initiation 38 47) Which one of the following, if missing, would usually prevent translation from starting? A) exon D) poly-A tail 39 48) Put the following events of
elongation in prokaryotic translation in chronological order. 1. Binding of mRNA with small ribosomal subunit 4. Base pairing of the mRNA codon following the initiator codon with its complementary tRNA 5. Attachment of the large subunit C) 5, 4, 3, 2, 1 40 49) How does termination of translation take place? A) The end of the mRNA molecule is reached. D) The poly-A tail is reached. 41 50) Post-translational modifications of proteins may include the _____. A) removal of introns D) addition of carbohydrates to form a glycoprotein 42 51) Which
of the following statements is true about protein synthesis in prokaryotes? B) Translation can begin while transcription is still in progress. 43 52) 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 C) a substitution of the third nucleotide in an ACC codon D) a substitution of the first nucleotide of a GGG codon 44 53) A nonsense mutation in a gene _____. C) introduces a premature stop codon into the mRNA 45 54) Which of the following DNA mutations is most likely to damage the protein it specifies? A) a base-pair deletion D) a codon deletion 46 55) The most commonly
occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in _____. C) a polypeptide missing an amino acid D) a nonsense mutation 47 56) Of the following, which is the most current description of a gene? D) a discrete unit of hereditary information that consists of a sequence of amino acids 48 57) How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene, and why? C) All amino acids following the substitution would be affected, because the reading frame would be shifted. 49 58) An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this DNA strand results in the base sequence AGGCGTTACCGT. This change represents _____. A) a missense mutation C) a silent mutation 50 59) A single base substitution mutation is least likely to be deleterious when the base change results in _____. C) an amino acid substitution that alters the tertiary structure of the protein D) an amino acid substitution at the active site of an enzyme 51 60) Rank the following one-base point mutations (from most likely to least likely) with respect to their likelihood of affecting the structure of the corresponding polypeptide. 3. substitution mutation at the second position of an exonic codon 4. deletion mutation within the first exon of the
gene C) 2, 1, 4, 3 What is a primary transcript in the nucleus of a eukaryotic cell?A primary transcript is the single-stranded ribonucleic acid (RNA) product synthesized by transcription of DNA, and processed to yield various mature RNA products such as mRNAs, tRNAs, and rRNAs. The primary transcripts designated to be mRNAs are modified in preparation for translation.
What is the primary transcript of eukaryotic genes quizlet?The primary transcript of a eukaryotic gene is modified in several ways before it leaves the nucleus: both ends of the pre- mRNA are modified, and the introns are removed. functional mRNA. Also known as the primary transcript. is added to the 5′ end of the pre-mRNA as it is transcribed.
Which is the first transcript in transcription process of eukaryotes?Eukaryotic transcription is referred to as the first step towards gene expression in which some segments of DNA are traced into RNA by a special enzyme called RNA polymerase. This results in forming an antiparallel RNA fibre known as a primary transcript.
What does primary RNA transcript mean and how is it different than the mRNA sequence?The primary RNA transcript contains both intronic and exonic regions. Explanation: The primary RNA contains introns and exons because it has not been processed yet, and therefore the introns have not been spliced out. Mature mRNA contains only exons, which are the coding sequences that ultimately get translated.
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