RNA has the function of copying genetic information from DNA and transporting it to be used for protein synthesis. It differs from DNA in that RNA is single-stranded, contains the sugar ribose instead of deoxyribose, and contains the base uracil instead of thymine. The length of mRNA is much shorter than DNA as it only contains the code for a single protein, while DNA contains the full genome.

1. Wednesday 28, March, 2012.
Biology:
Oscar Gonzalez
Team:
Rafael Oswaldo Sandoval Rodríguez
Serrano Edgar Humberto
Tramontini Tapia Mayko Vittorio
Williams Reyes Fernando Lamar

2. The Structure of RNA
 What is the function of RNA?
 DNA carries the genetic code that produces proteins
needed in our body. Among the DNA, there are bases
sequences or genes that are a coded description for
making a particular protein.
 We must know that proteins are not made inside the
nucleus of a cell, but rather outside of it, in the
cytoplasm, and to accomplish that, we need RNA.

3. The Structure of RNA
 First, RNA copies the information with a slight change
(which will be seen later). Then, it proceeds to go
outside the nucleus into the cytoplasm and synthesize
the information with the ribosomal RNA and the
transfer RNA.

4. The Structure of RNA
 How to differentiate RNA from DNA?
 The length is a very considerable variable, since DNA
is much longer because it contains the information for
making every protein we need, while mRNA contains
the information to transcribe one protein or
polypeptide chain.
 Their overall structure is also different, being DNA one
a double helix, and mRNA a single stranded one.

5. The Structure of RNA
 The sugar present in the back bone of the chain.
 In the RNA back bone, the deoxyribose group found in
DNA is replace by a sugar ribose.
 A different base.
 DNA bases are Adenine, Guanine, Cytosine and
Thymine, represented by their first letter, but in RNA,
Thymine is replaced by Uracil.

6. The Structure of RNA

7. DNA Strands

8. Steps of Transcription
 Pre-Initation:
 RNA polymerase and cofactors bind to DNA and
unwind it, creating an initiation bubble. This is a space
that grants RNA polymerase access to a single strand of
the DNA molecule.

9. Steps of Transcription
 Initiation:
 A group of proteins called transcription factors
mediate the binding of RNA polymerase and the
initiation of transcription.

10. Steps of Transcription
 Promoter Clearance:
 RNA polymerase must clear the promoter once the
first bond has been synthesized. Approximately 23
nucleotides must be synthesized before RNA
polymerase loses its tendency to slip away and
prematurely release the RNA transcript.

11. Steps of Transcription
 Elongation:
 One strand of DNA serves as the template for RNA
synthesis, but multiple rounds of transcription may
occur so that many copies of a gene may be produced.

12. Steps of Transcription
 Termination:
 Termination results in the release of the newly
synthesized mRNA from the elongation complex.

14. References
 http://www.chemguide.co.uk/organicprops/aminoaci
ds/dna3.html
 http://biology.about.com/od/cellularprocesses/ss/Dna
-Transcription.htm

15. Questionare
 Define transcription:
 What is the function of RNA?
 In the DNA´s structure, thymine is replaced by what base
in the RNA´s structure?
 The is a very considerable variable, since is
much longer because it contains the information for
making every protein we need, while mRNA contains the
information to transcribe one protein or polypeptide chain.
Their overall structure is also different, being DNA one a
, and mRNA a single stranded one.

16. Questionare
 Define de pre-initiation step:
 Establish the diference between elongation and
termination:
 Mention 5 diferences between the DNA´s structure
and the RNA´s structure:

17. Excersice
 DNA strand: A T T A C G A T C T G C A C A A G A C T T C
 Transcription
 MRNA strand: __________________________________________

 DNA strand: G T A C G A A T T G C C A A T T A C T
 Transcription
 MRNA strand: __________________________________________

 DNA strand: T A C G G A A T C G A T G C G C G C A C T
 Transcription
 MRNA strand: __________________________________________

 DNA strand: T A C C C A T G G G G A A A T A T C
 Transcription
 MRNA strand: __________________________________________

 DNA strand: G C G C T A C A A T T G G A T C G T
 Transcription
 MRNA strand: __________________________________________