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12–3 RNA and Protein Synthesis


									12–3 RNA and Protein Synthesis
                                                             __________ are coded DNA instructions
                                                              that control the production of proteins.
                                                            Genetic messages can be decoded by
                                                              copying part of the ____________
                                                              sequence from DNA into RNA.
                                                                  o RNA contains coded information
                                                                      for making ____________.
                                                        The Structure of RNA
                                                            _______ consists of a long chain of
                                                            Each nucleotide is made up of a __-
                                                              ________ ________, a ____________
                                                              group, and a _____________ ________.
There are three main differences between RNA and DNA:
    __________________________________________________________________________________
    __________________________________________________________________________________
    __________________________________________________________________________________
What are the three main types of RNA?
Types of RNA
    There are three main types of RNA:
           o _________________________
           o _________________________
           o _________________________
                                                          Messenger RNA (________) carries
                                                          copies of ______________ for
                                                          assembling amino acids into proteins.

Ribosomes are made up of proteins and ____________ ______ (rRNA).

                   During protein construction, __________ ________
                   (tRNA) transfers each amino acid to the ribosome.
What is transcription?

    RNA molecules are produced by copying part of a _____________ __________ of DNA into a
      _______________ _____________ in RNA. This process is called ___________________.
          o Transcription requires the enzyme _______ _______________.

During transcription, RNA polymerase binds to DNA and separates the DNA strands.
RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a
strand of RNA.

      RNA polymerase binds only to regions of DNA known as ___________.
         o Promoters are signals in DNA that indicate to the enzyme where to bind to make RNA.

RNA Editing
   The DNA of eukaryotic genes contains sequences of nucleotides, called ___________, that are not
     involved in coding for proteins.
   The DNA sequences that code for proteins are called ______________.
         o When RNA molecules are formed, introns and exons are copied from DNA.

The introns are ______ _____ of RNA molecules.

The exons are then __________ together to form

The Genetic Code
    The genetic code is the “___________” of mRNA
    The code is written using four “_________” (the
      bases: A, ________, C, and G).
                                                      A __________ consists of ________ consecutive
                                                       nucleotides on mRNA that specify a particular amino
                                                      Each codon specifies a particular _______ ______
                                                       that is to be placed on the polypeptide chain.
                                                      Some amino acids can be specified by more than one

      There is ____ codon _______ that can
       either specify the amino acid
       methionine or serve as a “______”
       codon for protein synthesis.
      There are ______ “______” codons
       that do not code for any amino acid.
       These “stop” codons signify the end of
       a ________________.

What is translation?
    ________________ is the decoding of
       an mRNA message into a polypeptide
       chain (protein).
           o Translation takes place on
During translation, the cell uses information
from messenger RNA to produce proteins.

      Messenger RNA is transcribed in the ______________, and then enters the ______________ where it
       attaches to a ________________.

      Translation begins when an ___________ molecule attaches to a ribosome.
      As each codon of the mRNA molecule moves through the ribosome, the proper _________ ______ is
       brought into the ribosome by tRNA.
          o In the ribosome, the amino acid is transferred to the growing polypeptide chain.
                                                                         The ribosome binds new
                                                                          _________ molecules and amino
                                                                          acids as it moves along the mRNA.

Protein Synthesis
The process continues until the ribosome reaches a stop codon.

The Roles of RNA and DNA
    The cell uses the DNA “________ _____” to prepare RNA “_____________.” The DNA stays in the
                            The RNA molecules go to the protein building sites in the cytoplasm—the
                        Genes and Proteins
                            _____________ contain instructions for assembling proteins.
                            Many proteins are ____________, which catalyze and regulate chemical
                            Proteins are each specifically designed to build or operate a component of a
                              living cell.

                         The sequence of bases in DNA is used as a _______________ for mRNA.
                         The codons of mRNA specify the sequence of amino acids in a protein.

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