biochem 012 DNA and protein synthesis part 3 (watson, crick, griffith, chargoff's rule, translation,

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biochem 012 DNA and protein synthesis part 3 (watson, crick, griffith, chargoff's rule, translation,
2014-12-04 11:42:15
biochem 012 DNA protein synthesis part watson crick griffith chargoff rule translation ribosomes mRNA 25
biochem 012 DNA and protein synthesis part 3 (watson, crick, griffith, chargoff's rule, translation, ribosomes, mRNA) #25
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  1. In 1909, British physician _____ _____ first suggested that genes dictate phenotypes through enzymes that catalyze specific chemical reactions
    Archibald Garrod
  2. _____ and _____ developed the ___ _____-__ ______ hypothesis
    Beadle and Tatum; one gene-one enzyme
  3. the one gene-one enzyme hypothesis was later revised to be...
    the one gene-one protein hypothesis and then to the one gene-one polypeptide hypothesis
  4. true or false? in prokaryotes, transcription immediately follows translation?
    false, translation immediately follows transcription
  5. In a eukaryotic cell, the _____ ______ separates transcription from translation
    nuclear envelope
  6. what is a primary transcript?
    the initial RNA transcript from any gene
  7. What is RNA processing?
    Eukaryotic RNA transcripts are modified through RNA processing to yield finished mRNA
  8. what type of nucleotide base code is used for the instructions for assembling amino acids into proteins?
    the flow of information from gene to protein is based on a triplet code: a series of nonoverlapping, three-nucleotide words. These triplets are the smallest units of uniform length that can code for all the amino acids. the mRNA base triplets are called codons.

    For example, AGT at a particular position on a DNA strand results in the placement of amino acid serine at the corresponding position of the polypeptide to be produced
  9. during translation codons are read how?
    they are read in the 5' to 3' direction
  10. how many codons are there and what do they code for?
    there are 64 triplets. 61 code for amino acids; 3 triplets are "stop" signals to end translation
  11. what is the reading frame?
    how the translational machinery of the cell reads the mRNA strand
  12. does RNA polymerase require single-strand binding proteins and topoisomerases?
    no, it pries open short sequences of the DNA strands as it moves along the DNA strands. The strands then rebind after the RNA polymerase has passed
  13. what are the terminator and the promoter?
    the DNA sequence where RNA polymerase attaches is called the promoter; in bacteria, the sequence signaling the end of transcription is called the terminator
  14. what is the transcription unit?
    the stretch of DNA that is transcribed is called a transcription unit
  15. what are the three stages of transcription?
    initiation, elongation, and termination
  16. _____ ______ mediate the binding of RNA polymerase and initiation of the transcription. when _____ ______ combine with ____ _______ __ bound to a promoter, the structure formed is called a ________ ______ _____
    transcription factors, transcription factors, RNA polymerase II, transcription initiation complex
  17. what is a TATA box?
    a promoter called a TATA box is crucial in forming the initiation complex in eukaryotes
  18. describe the mechanisms for termination in bacteria and eukaryotes
    in bacteria, the polymerase stops transcription at the end of the terminator.

    In eukaryotes, the polymerase continues transcription after the pre-mRNA is cleaved from the growing RNA chain; the polymerase eventually falls of the DNA
  19. where does RNA processing occur?
    in the nucleus
  20. what happens to the end of the pre-RNA during RNA processing?
    the 5' end receives a modified nucleotide 5' cap. The 3' end gets a poly-A tail
  21. what is the purpose of modifying the ends of the pre-mRNA
    • 1. they seem to facilitate the export of mRNA
    • 2. They protec mRNA from hydrolytic enzymes
    • 3. They help ribosomes attach to the 5' end