DNA-Structure-and-Replication by babbian

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									      AP Biology


DNA Structure & Replication
Nucleic Acid Structure
Complimentary Base Pairing
S Phase of Cell Cycle
    Theta
  Replication                                   Replication fork
in Prokaryotes
                 Origin of
                 replication




                               Termination
                               of replication
Linear Replication in Eukaryotes
.




    The parent molecule has
    two complementary
    strands of DNA. Each base
    is paired by hydrogen
    bonding with its specific
    partner, A with T and G with
    C.
 .




The parent molecule has        The first step in replication
two complementary              is separation of the two
strands of DNA. Each base      DNA strands.
is paired by hydrogen
bonding with its specific
partner, A with T and G with
C.
Semi Conservative process
   of DNA Replication




      The parent molecule has     The first step in replication   Each parental strand now
      two complementary           is separation of the two        serves as a template that
      strands of DNA. Each base   DNA strands.                    determines the order of
      is paired by hydrogen                                       nucleotides along a new,
      bonding with its specific                                   complementary strand.
      partner, A with T and G
      with C.
Origins and Replication bubbles
DNA Replication
DNA Replication by adding
Nucleosides on the 3’ end
            New strand         Template strand
              5 end               3 end                        5 end   3 end



      Sugar
                        Base
 Phosphate




                                            DNA polymerase
               3 end


                                                                 3 end
                                                 Pyrophosphate


            Nucleoside
           triphosphate            5 end                                 5 end
5 Carbon Sugar Important Parts
   (It could be DNA or RNA)
Helicase is the GREEN “blob”
RNA Primer on the LAGGING STRAND
  (Remember, RNA is temporary)
    Answer the following questions as a group—you do not have to
          write them down. Be prepared to answer aloud.

•    In which direction is DNA Replicated
•    Which enzyme unzips the DNA?
•    Which enzyme adds new nucleotides?
•    What holds the bubble open?
•    What are the short pieces of DNA created on the lagging
     strand called?
•    What must be laid down first before DNA can be copied?
•    Which enzyme stitches the new nucleotides together?
•    The mechanism of DNA Replication is called Semi-
     Conservative…why?
•    What turns a nucleoside into a nucleotide?
     .


          New strand        Template strand
            5 end              3 end                        5 end   3 end



   Sugar
                     Base
Phosphate




                                         DNA polymerase
            3 end


                                                              3 end
                                              Pyrophosphate


          Nucleoside
         triphosphate           5 end                                 5 end
Nucleotide Excision Repair
Telomere Removal                      5
                                                                 Leading strand
                   End of parental
     at the        DNA strands                                   Lagging strand
Chromosome Ends                       3



                                              Last fragment     Previous fragment

                                           RNA primer
                    Lagging strand 5
                                     3

                   Primer removed but                     Removal of primers and
                    cannot be replaced                    replacement with DNA
                     with DNA because                     where a 3 end is available
                     no 3 end available
                   for DNA polymerase
                                                5
                                     3
                                                          Second round
                                                          of replication

                                                5
                          New leading strand 3
                          New leading strand 5
                                     3
                                                          Further rounds
                                                          of replication

                                                Shorter and shorter
                                                daughter molecules
Apoptosis in the hand

								
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