URL

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???? ????????? ????????? (????)
2
URL

• http//research.haifa.ac.il/genom/Alex's_page/Lec
  tures.html
• http//research.haifa.ac.il/genom/Alex's_page/Lec
  tures.html

3
The Relationship between Genes and Proteins

• Most genes encode the information for the
  synthesis of a protein
• The sequence of bases in DNA codes for the
  sequence of amino acids in proteins

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The Central Dogma ???? ??????

• DNA carries the genetic material the
  information required by an organism to function.
  DNA is also the means by which organisms transfer
  genetic information to their descendants. In
  organisms with a nucleus (eukaryotes), DNA
  remains in the nucleus whereas proteins are made
  in the cytoplasm outside of the nucleus. The
  intermediate molecule carrying the information
  out of the nucleus is RNA. The information flow
  in biology is summarized by the "central dogma",
  put forward by Francis Crick in 1958 

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???? ??????

• The central dogma states that once 'information'
  has passed into protein it cannot get out again.
  The transfer of information from nucleic acid to
  nucleic acid, or from nucleic acid to protein ,
  may be possible , but transfer from protein to
  protein , or from protein to nucleic acid , is
  impossible.

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The Central Dogma
7
???? ????? ???? ?? ?????? ???
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Retro

• However, the "Central Dogma" has had to be
  revised a bit. It turns out that you CAN go back
  from RNA to DNA, and that RNA can also make
  copies of itself. It is still not possible to go
  from Proteins back to RNA or DNA, and no known
  mechanism has yet been demonstrated for proteins
  making copies of themselves.

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A revised central dogma
10
??????? ???"?
11
?????? ?? ??????? ???"?

• ???????? ?????? ???"? ????? ???? ????, ???? ??
  ???? ??????
• ????? ?????? ?? ??????? ?????? ???? ?????
  (Replication)

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????? (Replication)

• ????? ???? ??"? ??-?????,
• ???? ???"? ???-????? ??????

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????? (Replication)

• ?????-????? ???? ??"? ??-?????, ???? ???"?
  ???-????? ??????
• ????? ????? ?? ???"? ?????? ?????? ?????? ?? ????
  ?????? ?????? ?????
• ??????? ??????? ?????? ??????, ?? ?? ???? ?????
  ???????
• ?????? ??? ??-??????, ????? ???? ?????? (???? ???
  ????? ??????)

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???? ????? ??????? ???"?

• ???? 4 ???? ?????? )???????????( ???
• Adenine (A) , Cytyosine (C) , Guanine (G) ,
  Thymine (T)
• T ???? ?????? ?? ?? A ? T A ???? ???? 
• C ???? ?????? ?? ?? C ? G G ???? ????

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??????? ??????? ?????? ??????

• ???? ?????? ??? ?????? ???"? ??? ?????? ???????
  ???"? ???-????? ???-?????
• ???? (Denaturation) ????? ?? ??"? ??-????? ????
  ?????? ??????. ????? ?? ????? ????
• ?????? ????? ???? ???????? ??"? ??-?????, ???
  ??? ??????? ??????? ?? ?????
• ??? (Primer) ??? ?? ????? ??? ????? ????? ??
  ??"? ?????? ????? ?? ????? ???????? ????? ????
• ????? ?????????-??????? ??????? ???????? ????
  ????? ???????? ???????

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??????? ??????? ?????? ????????-???????Enzymes

• ??????? ?????? ?????? ????????? ?? ??? ?????
  ??????? ?????? ???????
• ??????? ?????? ?? ???????? ?? ??? ????? ?????????
  ?????? ????? ?????? ?????? ?? ????? ?? ?????

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??"? ???????? (DNA Polymerase)

• ????? ????? ?? ?????? ?? ??"? ????? ??????
• (G, C, A, T) ?? ?? ????? ?? DNA
• ??"? ???????? ???? ????? ???? ?????? ???"? ???
  ???? ???? (Primer)
• ??"? ???????? ????? ?? ????? ???"? ????? ??????
  '5 ?- '3

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???????

• file///c/Documents20and20Settings/Sasha/My20D
  ocuments/Courses/Introduction20to20the20World2
  0of20Viruses/2007/DNAreplication.html

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(No Transcript)
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(No Transcript)
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???"? ?????? ??? ??"? ????

• ??????? ???"? ??? ???? ?????? ????????? ??????
  ??? ???, ???? ?? ???? ????? ?? ???? ????? ?????
  ?? ???? ?????.
• ???? ?????? ?? ????? ??????? ??? ???? ??? ???????
  ?? ?????.
• ?????? ????"? ???? ?????? ??? ????????? ??????
  ???? ?????? ??? ???? ???? ?????? ?? ????? ??? ???
  ??????.???? ????? ?? ??? ??????? ???"? ?????.

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??"? RNA

• ???? ???? ?????? ?? ??? ????? ?? ??"? ??????
  ????? ???
• ????? ??????? ? U, A, G, C ????? T ???"?
• ??"? ???? ??? ???? ??-????? (??"? ???? ??-?????)
• ?????? ??????? ???"? ?????? ?????? ??-???????

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???"? ??????
?????
?????
??"?
??"?
?????
?????
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????? Transcription

• ???"? ???"?, ????? ??"? ??-?????
• ?? ??? ????? ?? ??"?

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????? Translation

• ???"? ??????, ????? ????? ??
• ????? ?? ?? ????? ???"?

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????? Transcription

• ??? (???"?) ?????? ???"? ?? ??? ?????? ??"?
  ???????? (RNA Polymerase)?????? '5 ?- '3
• ?????? ????? ????? ??? ???? ?? ??"?
• ?????? ????? ?????? ?????? ??? (???? ??? ???????)

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????? (????)
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????? (????)

• ????? ????? ??????
• ?????? (Initiation)- ??"? ???????? ???? ?????
  ???"? ????? ??? ???? ?????? ??????.
• ????? ????? ?????? ?????? ???? ????? ??????? ???
  ???? (Promoter)

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????? Transcription(????)

• ????? ????? ??????
• 2) ????? (Elongation)- ????? ???"? ???-?????
  ?????? ???? ?????.
• ??????? ?????? ?? ????"? ???????? ???? ?? ???
  ????? (Termination Site)

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????? Transcription(????)

• ????? ????? ??????
• 3) ???? (Termination)- ???? ?????
  ??????.
• ????? ?????? ?????? ?????? ??"? ????????
  ??????? (??"? ????messenger RNA mRNA ) ??????
  ????"?.
• ???"? ??????? ???? ?????? ???? ????? ????
  ???? ???????? ??? ??????? ?????????Ribosome
  (???????? ????? ??? ??????)

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???????

• file///c/Documents20and20Settings/Sasha/My20D
  ocuments/Courses/Introduction20to20the20World2
  0of20Viruses/2007/DNAtranscription.html

32
(No Transcript)
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(No Transcript)
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(No Transcript)
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The Genetic Code