Biology FRQ

FRQ #3

a) The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of biology. The role of RNA in protein synthesis is extremely important as protein synthesis could not occur without RNA. Three forms of RNA exist solely to create proteins. Through a process known as translation, RNA constructs the proteins necessary to sustain life. Spliceosomes Process pre-mRNA by splicing out intronic nucleic acids producing mRNA which is then translated to protein in ribosomes. Codons are three letter codes eg: AUG which codes for metheonine. Likewise there are many codons which code for different amino acids. Ribosomes bind to the mature mRNA at an AUG site and, for each codon (3 mRNA nucleic acids), a tRNA brings an amino acid for the translation, until the stop codon where the newly synthesized polypeptide is released in its primary structure.
b) A eukaryotic cell has a nucleus that separates the processes of transcription and translation. Eukaryotic transcription occurs within the nucleus where DNA is packaged into nucleosomes and higher order chromatin structures. Translation is the process by which messenger RNA is translated into proteins in eukaryotes.
c) Rabies is an RNA virus, so it deviates from the central dogma by the fact that it is storing it's genetic information in RNA instead of DNA. Eukaryotic cells use RNA as well, but only use it for an intermediate step when turning genetic information into protein. RNA is a much less stable molecule than DNA so it is not very good for holding the large amounts of DNA typically seen in Eukaryotic cells.