Download Chapter 13: The Genetic Code and Transcription

Chapter 13: The Genetic Code and Transcription
 The structure of DNA consists of a ____________________ sequence of deoxyribonucleotides. This sequence
dictates the components proteins, which are the end product of most genes.
 The information present of one of the two DNA strands (_______________ strand) is transferred into an RNA
complement through the process of ___________________. This RNA then acts as a
______________________ (mRNA) bearing the coded information.
 The mRNA then associates with ____________________ to decode the information and produce proteins in the
process of _______________________.
13.1 The genetic code exhibits a number of characteristics
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Deciphering the genetic code has revealed ________ triplet-codon amino acid assignments. The __________
remaining codons are termination signals and do not specify an amino acid. (total of 64 codons)
Initiation, Termination, and Suppression
 Experiments show that the initial amino acid inserted into all proteins is a form of _______________. Initiation
is a highly specific process. Only one codon, ______, codes for methionine and it is termed the initiator codon.
 Three other codons serve as _________ codons (_____, _____, and _____) but do not code for an amino acid.
Transcription synthesizes RNA on a DNA template
 The process begins with the transfer of the information stored in _____ to _____. This process is termed
transcription. It results in an mRNA molecule ___________________ to the strand of DNA from which it was
written. Each triplet in this mRNA is complementary to the anticodon of its corresponding tRNA. The tRNA
inserts the correct amino acid during the process of translation.
In 1959, the enzyme RNA ______________________ was discovered. It has the same substrate requirements as
DNA polymerase, but had the ribose sugar in it rather than the deoxyribose sugar. No primer is required to initiate
synthesis.
Promoters and Template Binding
 Transcription results in the synthesis of a ____________________________ RNA molecule complementary to
only _______________________ DNA strands. The initial step is called template binding; in it, RNA
polymerase subunits recognize specific DNA sequences called ___________________. The helix becomes
denatured and ______________________ locally, making the template accessible to the enzyme action.
Transcription begins at the transcription start site.
Initiation, Elongation, and Termination of RNA Synthesis
Once it has bound to the promoter, RNA polymerase catalyzes initiation and the insertion of the first ribonucleotide
at the start of the DNA template. _______________________ complements are inserted and linked together as
transcription proceeds. Chain elongation will proceed under the direction of an enzyme. Transcription will proceed
down the entire gene until it encounters a specific nucleotide sequence that acts as a termination sequence.
Initiation of Transcription in Eukaryotes
Eukaryotic RNA polymerase exists in three unique forms; each transcribes different types of genes. Each enzyme is
larger and more complex than the prokaryotic form
*from another text
Protein Synthesis
A. Two main processes of protein synthesis.
1. Transcription 2. Translation B. Transcription
1. Making RNA
2.
3. Transcription begins at a ____________________ on the DNA, a sequence of bases on the
DNA that tells the RNA to begin binding.
C. Translation –
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3 bases of mRNA =
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2. tRNA
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Each tRNA codon codes for a
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3.