biochem 012 DNA and protein synthesis part 1(watson, crick, griffith, chargoff's rule, translation,

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biochem 012 DNA and protein synthesis part 1(watson, crick, griffith, chargoff's rule, translation,
2014-12-01 21:29:00
biochem 012 DNA protein synthesis part watson crick griffith chargoff rule translation ribosomes mRNA 23
biochem 012 DNA and protein synthesis part 1(watson, crick, griffith, chargoff's rule, translation, ribosomes, mRNA) #23
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  1. _ _ ____ group showed that genes are located onchromosomes
    T. H. Morgan’s
  2. the two components of chromosomes—____ and _____—were candidates for the genetic material
    DNA and protein
  3. explain Griffith's experiment
  4. what is transformation?
    a change ingenotype and phenotype due to assimilation of foreign DNA
  5. What was Griffith's discovery?
    The discovery of the genetic role of DNA
  6. In 1952, ____ _____  and ____ ____ performed experiments showing that DNA is the genetic material of a phage known as T2
    Alfred Hershey, Martha Chase
  7. what is chargaff's rule?
    Chargaff’s rules state that in any species there is an equal number of A andT bases, and an equal number of G and C bases
  8. Watson and Crick initially thought the bases were paired how?
    At first, Watson and Crick thought the bases paired like with like (A with A,and so on), but such pairings did not result in a uniform width
  9. Experiments by _______ and _____ supported thesemiconservative model. They did this by...
    Mendelson and Stahl. They labeled the nucleotides of the old strands with a heavy isotope ofnitrogen, while any new nucleotides were labeled with a lighter isotope
  10. what other models of DNA replication were being considered besides semiconservative?
    Competing models were the conservative model (the two parent strandsrejoin) and the dispersive model (each strand is a mix of old and new)
  11. what is an origin of replication?
    Replication begins at special sites called origins of replication, where thetwo DNA strands are separated, opening up a replication “bubble”
  12. what is a replication fork?
    At the end of each replication bubble is a replication fork, a Y-shapedregion where new DNA strands are elongating
  13. what is a single-strand binding protein?
    Single-strand binding protein binds to and stabilizes single-stranded DNAuntil it can be used as a template
  14. what do topoisomerases do?
    Topoisomerase corrects “overwinding” ahead of replication forks bybreaking, swiveling, and rejoining DNA strands
  15. can DNA initiate synthesis of a polynucleotide? Explain
    DNA polymerases cannot initiate synthesis of a polynucleotide; they canonly add nucleotides to the 3ʹ′ end of a short, initial nucleotide strand, which is called an RNA primer
  16. what is primase?
    An enzyme called primase can start an RNA chain from scratch and addsRNA nucleotides one at a time using the parental DNA as a template
  17. what is the difference between dATP and ATP?
    The difference is in their sugars: dATP has deoxyribose while ATP hasribose
  18. what occurs to dATP when it joins the DNA strand?
    As each monomer of dATP joins the DNA strand, it loses two phosphategroups as a molecule of pyrophosphate
  19. describe the lagging strand and leading strand
  20. The lagging strand is synthesized as a series of segments called _______ ________, which are joined together by ___ ______.
    Okazaki fragments, DNA ligase
  21. is each protein involved in transcription completely separate from the other proteins involved in transcription?
    No, the proteins that participate in DNA replication form a large complex, a“DNA replication machine”
  22. true or false? DNA helicase proofreads and repairs the DNA.
    false. DNA polymerases proofread newly made DNA, replacing any incorrectnucleotides