Biology

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Author:
tiamaria91
ID:
79171
Filename:
Biology
Updated:
2011-04-14 19:33:47
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DNA etc
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Description:
biology notes
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  1. DNA has the capacity to:
    and can be:
    • store genetic information
    • copied and passed from generation to generation
  2. DNA and RNA are ____ _____
    nucleic acids
  3. chemical units that DNA and RNA are consisted of
    nucleotides
  4. joins nucleotides
    sugar-phosphate backbone
  5. DNA backbone consists of:
    deoxyribose sugars and phosphate groups (sugar-posphate backbone)
  6. The four nucleotides found in DNA differ in their nitrogenous bases:

    RNA has _ instead of _
    T, C, A, and G; U instead of T
  7. The model of DNA is like a rope ladder twisted into a spiral
    -The ropes at the sides represent the _______
    -Each wooden rung represents _______
    • -sugar-phosphate backbones
    • -a pair of bases connected to hydrogen bonds
  8. DNA bases pair in a complementary fashion:
    Why?
    • -A with T
    • -C with G
    • -Because of the number of hydrogen bonds they want to make
  9. When a cell reproduces, a complete copy of the DNA must _____

    Watson and Crick's model for DNA suggested that _______
    • -pass from one generation to the next
    • -DNA replicates by a template (patterned) mechanism
  10. DNA can be damaged by ____
    ultraviolet light
  11. enzymes that make the covalent bonds between the nucleotides of a new DNA strand; they are involved in repairing damaged DNA
    DNA polymerases
  12. DNA replication in eukaryotes:
    -Begins at specific sites on a ____ ____
    -Proceeds __________
    • -double helix
    • -in both directions
  13. DNA functions as the ________
    inherited directions for a cell or organism
  14. An organism's genetic makeup; the sequence of nucleotide bases in DNA
    genotype
  15. the organism's physical traits, which arise from the actions of a wide variety of proteins
    phenotype
  16. DNA specifies the synthesis of proteins into two stages: ___ and ___
    transcription and translation
  17. the transfer of genetic information from DNA into an RNA molecule
    transcription
  18. the transfer of information from RNA into a protein
    translation
  19. -The function of a gene is to ____
    -A protein may consist of two or more different ___
    • -dictate the production of a polypeptide
    • -polypeptides
  20. Genetic information in DNA is:
    1.
    2.
    • 1. transcribed into RNA, then
    • 2. translated into polypeptides
  21. What is the language of nucleic acids?
    • -in DNA, it is the linear sequence of nucleotide bases
    • -a typical gene consists of thousands of nucleotides
    • -a single DNA molecule may contain thousands of genes
  22. When DNA is transcribed, the result is ____
    an RNA molecule
  23. RNA is then translated into _____
    a sequence of amino acids in a polypeptide
  24. a triplet of bases which codes for one amino acid
    codon
  25. the set of rules relating nucleotide sequence to amino acid sequence; shared by all organisms
    genetic code
  26. of the 64 triplets:
    • -61 code for amino acids
    • -3 are stop codons, indicating the end of a polypeptide
  27. Transcription
    • -DNA to RNA
    • -makes RNA from a DNA template
  28. links RNA nucleotides
    RNA polymerase
  29. RNA substitutes a _ for a _
    U for a T
  30. Initiation of Transcription
    • -first phase of transcription
    • -RNA polymerase attaches to the promoter
    • -RNA synthesis begins
  31. a nucleotide sequence with the "start transcribing" signal
    promoter
  32. RNA elongation
    • -second phase of transcription
    • -RNA grows longer
    • -RNA strand peels away from the DNA template
  33. Termination of Transcription
    • -third phase of transcription
    • -RNA polymerase reaches terminator
    • -polymerase detaches from the RNA
    • -the DNA strands rejoin
  34. After transcription, before translation
    • -eukaryotic cells process RNA
    • -prokaryotic cells do not
  35. RNA processing
    • -adding a cap and tail
    • -removing introns
    • -splicing exons together to form messenger RNA
  36. the conversion from the nucleic acid language to the protein language
    translation
  37. Translation requires:
    • -mRNA
    • -ATP
    • -enzymes
    • -ribosomes
    • -transfer RNA
  38. Transfer RNA (tRNA)
    • -acts as a molecular interpreter
    • -carries amino acids
    • -matches amino acids with codons in mRNA using anticodons
  39. Ribosomes:
    • -coordinate the functions of mRNA and tRNA
    • -are made of two protein subunits
    • -make proteins
    • -contain ribosomal RNA (rRNA)
  40. Initiation during Translation:
    • brings together:
    • -mRNA
    • -the first amino acid, Met, with its attached tRNA
    • -two subunits of the ribosome
  41. the mRNA molecule has a ___ and a ____ that help it bind to the ribosome
    cap and a tail
  42. Initiation of Translation occurs in two steps:
    • -first, mRNA molecule binds to a small ribosomal unit, then an initiator tRNA binds to the start codon
    • -second, a large ribosomal subunit binds, creating a functional ribosome
  43. Elongation of Translation occurs in ____ steps:
    three steps
  44. the anticodon of an incoming tRNA pairs with the mRNA codon at the A site of the ribosome
    codon recognition; first step in elongation during translation
  45. the polypeptide leaves the tRNA in the P site and attaches to the amino acid on the tRNA in the A site; the ribosome catalyzes or activates the bond formation between the two amino acids
    peptide bond formation; second step in elongation during translation
  46. the P site tRNA leaves the ribosome; the tRNA carrying the polypeptide moves from the A to the P site
    translocation; third step in elongation during translation
  47. Termination: elongation continues until:
    • -the ribosome reaches a stop codon
    • -the completed polypeptide is freed
    • -the ribosome splits into its subunits
  48. in a cell, genetic information flows from DNA to RNA in the ______ and RNA to protein in the ______
    nucleus; cytoplasm
  49. any change in the nucleotide sequence of DNA
    mutation
  50. the replacement of one base by another
    base substitution
  51. the loss of a nucleotide
    nucleotide deletion
  52. the addition of a nucleotide
    nucleotide insertion
  53. insertions and deletions can:
    -change the reading frame of the genetic message
  54. physical or chemical agents that may cause mutations
    mutagens
  55. Viruses are not living organisms because they:
    -are not cellular and cannot reproduce on their own
  56. viruses that attack bacteria
    bacteriophages
  57. the first reproductive cycle of phages; many copies of the phage are made within the bacterial cell and then the bacterium lyses or breaks down
    lytic cycle
  58. the second reproductive cycle of phages; the phage DNA inserts into the bacterial chromosome and the bacterium reproduces normally, copying the phage at each cell division
    lysogenic cycle
  59. an enzyme used by retroviruses to synthesize DNA on an RNA template
    reverse transcriptase
  60. misfolded proteins that somehow convert normal proteins to the misfolded prion version; give an example
    prions; mad cow disease

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