1 In trying to determine whether DNA or protein is the genetic material Hershey and Chase made use of which of the following facts DNA contains phosphorus whereas protein does not 2 Nucleotide organic molecule made of three parts nitrogen base 5 carbon sugar pentose ribose or deoxyribose and a phosphate group w o phosphate group called nucleoside Make up DNA and RNA molecules Pyrimidine six membered ring carbon nitrogen Cytosine C Thymine T Uracil U Purine six membered ring fused to 5 membered Adenine A and Guarine G T only in DNA U only in RNA In an analysis of the nucleotide composition of DNA which of the following will be found A C G T Which of the following descriptions best fits the class of molecules known as nucleotides a nitrogenous base a phosphate group and a pentose sugar 3 Ribose in RNA Deoxyribose in DNA Only difference DeOXYribose lacks an oxygen atom on the second carbon in the ring Sugar atoms carry prime DNA Polymerase uses primer usually made of RNA therefore they think RNA evolved first and it was the building block of many early primitive organisms RNA is single stranded short nuc chain DNA is double long nuc chain DNA is self replicating RNA is synthesized from DNA 4 A T C G A T 100 A T C G C G C G 2 C Cytosine makes up 42 of the nucleotides in a sample of DNA from an organism Approx what percentage of the nucleotides in this sample will be thymine 8 5 More hydrogen bonding More CG Less AT Higher Temperature Melting Pt 6 What is meant by the description antiparallel regarding the strands that make up DNA The 5 to 3 direction of one strand runs counter to the 5 to 3 direction of the other strand 7 Replication in prokaryotes differs from replication in eukaryotes for which of the following reasons Prokaryotic chromosomes have a single origin of replication whereas eukaryotic chromosomes have many Both contain ribosomes RNA is PRIMITIVE component 8 DNA Synthesis primer molecule String I nucleotides What is the function of DNA polymerase III To add nucleotides to the 3 end a growing DNA strand 9 What enzyme catalyzes the elongation of a DNA strand in the 5 3 direction DNA polymerase III 10 A new DNA stand elongates only in the 5 to 3 direction because DNA polymerase can only add nucleotides to the free 3 end 11 I Helicase separates DNA strands during replication II DNA poly III III Ligase covalently connects segments of DNA elongation of lagging strand during DNA replication Joins Okazaki fragments together IV DNA poly I removes RNA nucleotides from the primer and adds equiv DNA to the 3 end of Okazaki fragments V Primase synthesizes short segments of RNA What is the function of topoisomerase Relieving strain in the DNA ahead of the replication fork An okazaki fragment has which of the following arrangement 5 RNA nucleotides DNA nucleotides 3 12 Telomerase catalyzes the lengthening of telomeres in Euk germ cells This restores their original length and compensates for shortening from DNA replication Which of the following would you expect of a eukaryote lacking telomerase a reduction in chromosome length in gametes The enzyme telomerase solves the problem of replication at the ends of linear chromosomes by which method Adding numerous short DNA sequences which form a hairpin turn 13 Which of the following does not occur in prokaryotic gene expression but does in eukaryotic expression A poly A tail is added to the 3 end of an mRNA and a cap is added to the 5 end 14 A part of the promoter called the TATA box is said to be highly conserved in evolution Which of the following might this illustrate Any mutation in the sequence is selected against The TATA sequence is found only several nucleotides away from the start site of transcription This relates to which of the following The number of hydrogen bonds between A and T in DNA In eukaryotes general transcription factors bind to other proteins or to a sequence element within the promoter called the TATA box 15 See pictures on last page 16 Ribozyme RNA which plays a central role in protein sythesis can also carry out enzyme like catalytic functions These RNA catalysts were called ribozymes Can make complementary short pieces of RNA provided that they are supplied with nucleotide building blocks What is a ribozyme an RNA with enzymatic activity 17 Codon mRNA base triplet Written in 5 3 direction Which of the following is not true of a codon It extends from one end of a tRNA molecule What is the effect of a nonsense mutation in a gene It introduces a premature stop codon into the mRNA What is the function of the release factor RF It binds to the stop codon in the A site in place of a tRNA 18 See pictures on last page 19 What type of bonding is responsible for maintaining the shape of the tRNA molecule hydrogen bonding between base pairs 20 A particular triplet of bases in the coding sequence of DNA is AAA The anticodon on the tRNA that binds the mRNA codon is UUU The anticodon loop of the first tRNA that will complement this mRNA is 3 GGC 5 21 Why might a point mutation in DNA make a difference in the level of protein s activity It might substitute an amino acid in the active site 22 A frameshift mutation could result from either an insertion or a deletion of a base 23 In eukaryotic cells transcription cannot begin until several transcription factors have bound to the promoter requires several TF s RNA polymerase Substrate must be present 24 Why are viruses called obligate intracellular parasites Use host cell s amino acids to synthesize proteins nucleotides for transcription replication metabolic enzymes and pathways to obtain energy ribosomes to synthesize proteins 25 Which of the following is characteristic of the lytic cycle A large number of phages are released at a time 26 Which of the following statements describes the lysogenic cycle of lambda phage The phage genome replicates along with the host genome 27 Viral envelopes can best be analyzed with which of the following techniques antibodies against specific proteins not found in the host membranes Enveloped viruses Any of the viruses with a lipoprotein envelope surrounding the nucleoprotein core of the virus 28 What is the function of reverse transcriptase in retroviruses It uses viral RNA as a template for DNA synthesis 29 Sodium In Potassium Out Calcium ions initiate the sliding of filaments in skeletal muscles by Bind to troponin complex reclose tropomyosin 30 The anticodon loop of the first tRNA that will complement this mRNA is 3 GGC 5 31 In response to
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