Chem 221 Quiz Exam Written With Accurate Answers

What distinguishes nucleotides from nucleosides? - Correct Answers Nucleosides lack the phosphate group. Which of the following is the most distinguishing difference between a purine and a pyrymidine - Correct Answers purines are double ring structures while pyrimidines have a single ring Which of the following bases is not found in RNA? - Correct Answers T The fundamental differences between RNA and DNA are - Correct Answers bases and the ribose units only The backbone of nucleic acids consists of - Correct Answers a phosphodiester bond between the 3' and 5' hydroxyl groups of neighboring sugars Which best describes the relationship between the nucleobases in a piece of DNA? - Correct AnswersThey are perpendicular to the helical axis. Which of the following statements is true for double-stranded DNA? Question options: The amount of A is the same as the amount of T, and the amount of G is the same as the amount of C. The amount of A is the same as the amount of G, and the amount of T is the same as the amount of C. The amount of A is the same as the amount of C, and the amount of G is the same as the amount of T. More than one of the above is true. - Correct AnswersMore than one of the above is true. Histones are proteins that - Correct Answersare frequently associated with eukaryotic DNA The strands in the double helix have their strands... - Correct Answershave their 3' → 5' directions opposed, i.e., they are anti-parallel. T/F Comparison of DNA sequences between widely diverse organisms indicates that all organisms have genetic similarity. - Correct AnswersTrue Supercoiling of DNA - Correct Answersrequires the action of topoisomerase enzymes Topoisomerases are associated with - Correct Answerssupercoiling of DNA. The three dimensional structure of nucleic acids can include all except: Supercoiling Base stacking Hairpin loops Circular molecules All of these can be included in the three dimensional structure - Correct AnswersAll of these can be included in the three dimensional structure Which piece of DNA will have the higher Tm, one with a cytosine plus guanine content of 30% or one with a cytosine plus guanine content of 50% if both are heated under the same experimental conditions? Question options: 30% cytosine plus guanine will have the higher Tm. 50% cytosine plus guanine will have the higher Tm. Their Tm's will be the same. There's no way to predict for this information. - Correct Answers50% cytosine plus guanine will have the higher Tm The Tm for melting the double helix is: - Correct AnswersThe midpoint of the range over which the helix denatures. Which of the following statements concerning small nuclear RNA is true? Question options: This RNA is usually found in snurps. This RNA is involved in removing exons from the RNA. This RNA was the first RNA shown to have catalytic activity. This RNA is small in size. All of these describe small nuclear RNA. - Correct AnswersAll of these describe small nuclear RNA. Transfer RNA molecules are characterized by all the following, except: - Correct AnswersThey are one of the largest of the RNAs. The duplication process of DNA is called - Correct AnswersReplication The production of RNA on a DNA template is called - Correct AnswersTranscription The process by which an mRNA base sequence directs the amino acid sequence of a protein is called - Correct AnswersTranslation The flow of genetic information is RNA → DNA in - Correct AnswersRetroviruses Which of the following is NOT an observed event in the flow of genetic information? - Correct AnswersProtein -- RNA What is the requirement for a template strand in DNA replication? - Correct AnswersIt serves as a guide in determining the next nucleotide to be added according to the Watson-Crick base pairing scheme. In the original Central Dogma of biology, the ordinary flow of genetic information is: - Correct AnswersDNA → RNA → Protein Semiconservative replication implies that - Correct Answerseach of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand. The famous Meselson and Stahl experiment showed: Question options: DNA is replicated by a semi-conservative mechanism. The direction of DNA synthesis proceeds 5' → 3'. The isotope 15N is denser than 14N. DNA replication is semi-conservative and 15N is denser than 14N. All of these are correct. - Correct AnswersAll of these are correc All the following describe the general mechanism of DNA synthesis, except: Question options: From the perspective of the DNA template strands, one strand is made 5' → 3' while the other strand is made 3' → 5'. The strands become separated during synthesis.