Chem. Ch 21

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Chem. Ch 21
2010-04-26 00:24:04
Chem 21

Chem. Ch 21
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  1. What are molecules that store information for cellular growth and reproduction?
    Nucleic acids
  2. DNA and RNA are both made up of what?
    Nucleic acids
  3. Nucleic acids are large molecules consisting of long chains of monomers called _____.
  4. The nucleic acids DNA and RNA consist of monomers called nucleotides that consist of what 3 structures?
    Pentose sugar, Nitrogen-containing base, Phosphate
  5. What are the 2 types of nitrogen bases in DNA and RNA?
    Pyrimidines & Purines
  6. What are the 3 letters associated with pyrimidines?
    C, T, & U
  7. What are the 2 letters associated with purines?
    A & G
  8. Both DNA and RNA have the nitrogen bases C, G, and A; but which has the nitrogen base T and which has the nitrogen base U?
    DNA (T) & RNA (U)
  9. Both DNA and RNA have a pentose (5-carbon) sugar, but what type of sugar is in in RNA and what type is it in DNA?
    RNA (Ribose) & DNA (Deoxyribose)
  10. How do you know if a pentose sugar is ribose or deoxyribose?
    A ribose sugar has an O on the #2 carbon, while a dexoyribose sugar doesn’t.
  11. A nucleoside has a nitrogen base linked by what type of bond?
    A glycosidic bond
  12. How do you name a nucleoside when it’s a purine vs. when it’s a pyrimidine?
    Purines end with –osine & Pyrimidines end with –idine.
  13. What is a nucleotide?
    A nucleoside that forms a phosphate ester with the C5’ –OH group of a sugar.
  14. How are nucleotides named?
    Using the name of the nucleoside followed by 5’-monophosphate
  15. What is formed when the –OH on C5’ sugar bonds to phosphoric acid?
    A nucleotide
  16. “A” stands for the nitrogen base Adenine. So how would you name this as a nucleoside and nucleotide if it were from RNA and DNA?
    RNA = Nucleoside (Adenosine) & Nucleotide (Adenosine 5’-monophosphate [AMP]) / DNA = Nucleoside (deoxyadenosine) & Nucleotide (Deoxyadenosine 5’-monophosphate [dAMP])
  17. Adding phosphate group to AMP forms what 2 other molecules?
    The diphosphate ADP & the triphosphate ATP.
  18. In the primary structure of nucleic acids, nucleotides are joined by what type of bond?
    Phosphodiester bonds
  19. In the primary structure of nucleic acids, the 3’-OH group of the sugar in one nucleotide forms what type of bond to the phosphate group on the 5’-carbon of the sugar of the next nucleotide?
    Ester bond
  20. A nucleic acid polmer has what on its ends?
    A free 5’-phosphate group on one end and a free 3’-OH group at the other end.
  21. From which end is a nucleic acid polymer read?
    From the free 5’-end
  22. The primary structure of RNA is a (single/double) strand of nucleotides.
  23. The primary structure of DNA is a (single/double) strand of nucleotides.
  24. What are the 4 bases of RNA?
    A,C,G, & U
  25. The primary structure of RNA have bases lined by (3’-5’ or 5’-3’) ester bonds between ribose and phosphate.
  26. What are the 4 bases of DNA?
    A,C,G, & T
  27. RNA and DNA have what type of bond between their sugar and phosphate?
  28. The DNA structure is what shape?
    A double helix
  29. (RNA or DNA) consists of two strands of nucleotides that form a double helix structure like a spiral stare case.
  30. Why is DNA said be like a spiral stair case?
    Because of its double helix shape
  31. What type of bond links the bases in DNA?
  32. DNA has bases along one strand that do what for the bases along the other?
  33. DNA contains complementary base pairs in which adenine is always linked by how many hydrogen bonds to thymine and guanine is always linked by how many hydrogen bonds to cytosine?
    A-T = 2 H & G-C= 3H
  34. In DNA, what are the complementary base pairs for A & G?
    A=T & G=C
  35. What is the complementary base sequence for the matching strand in the following DNA section: 5’-A-G-T-C-C-A-3’?
  36. DNA ______ involves unwinding the DNA.
  37. What is it called when the bases in each strand of DNA are paired with new bases to form new complementary strands?
    DNA replication
  38. What is produced by DNA replication?
    Two new DNA strands that exactly duplicate the original DNA
  39. Energy from the hydrolysis of each nucleoside triphosphate adding to the complementary strand is used to form the _________ bond.
  40. During DNA replication, what enzyme unwinds the parent DNA?
  41. During DNA replication, what are the open DNA sections called?
    A Replication Fork
  42. During DNA replication, what catalyzes the formation of 5’-3’ ester bonds of the leading strand?
    DNA polymerase
  43. During DNA replication, which is the lagging strand and which is the leading strand?
    The leading strand grows from 5’-3’ and the lagging strand grows from 3’-5’.
  44. During DNA replication, the lagging strand is synthesized in short sections called what?
    Okazaki fragments
  45. During DNA replication, the Okazaki fragments are joined by what to give a single 3’-5’ DNA strand?
    DNA Ligase
  46. What transmits information from DNA to make proteins?
  47. What are the 3 types of RNA?
    Messenger RNA (mRNA), Transfer RNA (tRNA), and Ribosomal RNA (rRNA).
  48. What is the function of mRNA?
    It carries genetic info from DNA to ribosomes
  49. What is the function of tRNA?
    It brings amino acids to the ribosome to make the protein.
  50. What is the function of rRNA?
    It makes up 75% of ribosomes where protein sythesis takes place.
  51. Each tRNA has a triplet called what?
    An anticodon
  52. What is the function of an anticodon?
    They complement the codon of mRNA
  53. Each what bonds to a specific amino acid at the acceptor stem?
  54. Protein synthesis involves what 2 functions?
    Transcription and Translation
  55. What is the outcome of transcription?
    mRNA is formed from a gene on a DNA strand.
  56. What is the outcome of translation?
    tRNA molecules bring amino acids to mRNA to build a protein.
  57. In (transcription or translation) a section of DNA containing the gene unwinds.
  58. What are the 4 steps in transcription?
    Unwind, Copy, mRNA formation, mRNA goes to ribosomes
  59. During transcription, what moves along the DNA template in the 3’-5’ direction to synthesize the corresponding mRNA?
    RNA polymerase
  60. During transcription, the what is released at the termination point?
  61. The DNA of eukaryotes contains ______ that code for proteins along with ____ that do not.
    Exons; Introns
  62. The initial mRNA called a pre-RNA includes the (coding or noncoding) intorns.
    Noncoding introns
  63. While in the nucleus, the what are removed from the pre-RNA?
  64. The exons that remain on pre-RNA are joined to form the what that leaves the nucleus with the info for the synthesis of protein?
  65. Transcription is regulated by a specific mRNA synthesized when?
    When the cell requires a particular protein
  66. Transcription is regulated by __________, in which the end products speed up or slow the synthesis of mRNA.
    Feedback control
  67. Transcription is regulated by ________, in which high levels of a reactant induce the transcription process to provide the necessary enzymes for the reactant.
    Enzyme induction
  68. What consists of a control site and the genes that produce mRNA for lactose enzymes?
    Lactose operon
  69. When there is no lactose in the cell, a regulatory gene does what?
    Produces a repressor protein that prevents the synthesis of lactose enzymes
  70. A repressor protein does what?
    Turn off mRNA synthesis.
  71. When lactose is present in the cell, some lactose combines with the repressor, which then does what?
    Removes the repressor from the control site
  72. Without the repressor gene what happens?
    RNA polymerase catalyzes the synthesis of the enzymes by the genes in the operon
  73. The level of lactose in a the cell induces the synthesis of the enzymes required for its _______.
  74. The _____ is a sequence of amino acids in a mRNA that determine the amino acid order for the protein.
    Genetic code
  75. The genetic code consists of sets of 3 bases (triplet) along the mRNA called ____.
  76. The genetic code has a different codon for the how many amino acids needed to build a protein?
  77. The genetic code contains certain _____ that signal the start and end of a polypeptide chain.
  78. There are specific condons that code for “start” and “stop”. What is the code for “start” and what are the 3 codes for stop?
    Start = AUG and Stop = UAA, UAG, and UGA
  79. What are the 2 Pros and 1 Con to the Genetic Code System?
    Pros = Highly degenerate (allows some room for error) & somewhat mutation-resistant, Cons = if the 1st base codes wrong then the whole amino acid is wrong
  80. The activation of tRNA occurs when a ________ uses energy of ATP hydrolysis to attach an amino acid to a specific tRNA.
  81. The activation of tRNA prepares each tRNA to use a triplet called an ______ to complement a codon on mRNA.
  82. What are the 4 steps to initiating protein synthese?
    mRNA attaches to a ribosome, the start codon binds to tRNA, the next condon attaches to a tRNA, a peptide bond forms between the two codons
  83. What are the 5 steps to translocation?
    The 1st tRNA detaches from the ribosome, the ribosome shifts to the adjacent codon on the mRNA, the new tRNA/amino acid attaches to the open binding site, a peptide bond forms when the tRNA detaches, and then the ribosome shifts down the mRNA to read the next codon
  84. What are the 4 steps in terminating protein synthesis?
    All the amino acids for the protein are synthesized, ribosomes reach the stop codon, protein synthesis ends, and then the polypeptide detaches from the ribosome.
  85. True or False: In the termination of protein synthesis, the ribosome reaches a stop codon but there is no tRNA with an anticodon for the “stop” condons.
  86. What alters the nucleotide sequence in DNA?
    A mutation
  87. A mutation results from what? Give 2 examples.
    Mutagens such as radiation and chemicals
  88. True or False: A mutation has to produce MORE than one incorrect codon to in the corresponding mRNA.
    False, it can produce one or more incorrect codons
  89. What causes a genetic disease that produce defective proteins and enzymes?
    A mutation
  90. What is the function of a normal DNA sequence?
    To produce a mRNA that provides instructions for the correct series of amino acids in a protein
  91. What happens in a substitution mutation?
    A different base substitutes for the proper base in DNA
  92. In a substitution mutation, there is a change in a codon in the mRNA which leads to the wrong _________ being placed in the polypeptide.
    Amino acid
  93. What happens in a frame shift mutation?
    An extra base adds to or is deleted from the normal DNA sequence so all the codons in the mRNA and amino acids are incorrect from the base change.
  94. What happens in recombinant DNA?
    A DNA fragment from one organism is combined with DNA in another.
  95. In recombinant DNA, what are used to cleave a gene from a foreign DNA and open DNA plasmids in E. coli.?
    Restriction enzymes
  96. In recombinant DNA, DNA fragments are mixed with the plasmids in E. coli and the ends are joined by _____.
  97. In recombinant DNA, the new gene in the altered DNA produces what?
  98. What are the 3 steps DNA fingerprinting (Southern transfer)?
    Restriction enzymes cut a DNA sample into smaller fragments (RFLPs), the fragments are sorted by size, the radioactive isotope that adheres to certain base sequences in the fragments produces a pattern on the X-ray film which is the “fingerprint”.
  99. True or False: In DNA fingerprinting, the “fingerprint” is unique to each individual DNA.
  100. What are the 4 steps in the polymerase chain reaction (PCR)?
    Produces multiple copies of a DNA in a short time, separates the sample DNA strands by heating, mixes the separated strands with enzymes and nucleotides to form complementary strands, and its repeated many times to produce a large sample of the DNA
  101. What are small particles of DNA or RNA that require a host cell to replicate?
    A viruses
  102. How are viruses synthesized in the host cell?
    From the viral RNA produced by viral DNA.
  103. In reverse transcription, a ______, which contains viral RNA, but no viral DNA, enters a cell.
  104. In reverse transcription, the viral RNA uses __________ to produce a viral DNA strand.
    Reverse transcriptase
  105. In reverse transcription, the viral DNA strand forms a complementary DNA strand. The new DNA uses what in the host cell to synthesize new virus particles.
    Nucleotides and enzymes
  106. What is the HIV-1 virus?
    A retrovirus that infects T4 lymphocyte cells.
  107. What decreases the T4 level making the immune system unable to destroy harmful organisms?
    The HIV-1 virus
  108. The HIV-1 virus causes pneumonia and skin cancer associated with what?
  109. One type of AIDS treatment prevents reverse transcription of the viral DNA by introducing what?
    Altered nucleosides such as AZT and ddl, which when incorporated into viral DNA, the virus is unable to replicate
  110. One type of AIDS treatment involves protease inhibitors such as saquinavir, indinavir, and ritonavir. What is the function of protease inhibitors?
    To modify the active site of the protease enzyme, which prevents the synthesis of viral proteins.
  111. What does Y and Z stand for: Viral RNA à Y à Viral DNA à Z à Viral Proteins?
    Y= Reverse transcriptase, Z= Protease