Changes

A '''Ribonucleic acid''' (RNA) is a molecule found in all cells, comprised of many individual units of [[nucleic acid]].  It differs from DNA ([[deoxyribonucleic acid]]) in that it only contains a single, not double strand, and substitutes [[uracil]] for [[thymine]].  The sugar backbone of RNA is also conposed of ribose (DNA contains deoxyribose). RNAs fall into several different categories, depending on function.   

A '''Ribonucleic acid''' (RNA) is a molecule found in all cells, comprised of many individual units of [[nucleic acid]].  It differs from DNA ([[deoxyribonucleic acid]]) in that it only contains a single, not double strand, and substitutes [[uracil]] for [[thymine]].  The sugar backbone of RNA is also conposed of ribose (DNA contains deoxyribose). RNAs fall into several different categories, depending on function.   

The primary role of mRNA in is to transfer a copy of the information coded in DNA to a [[ribosome]] to be expressed as a protein, using a form of RNA known as messenger RNA ([[mRNA]]).  mRNA in eukaryotes undergoes spicing after transcription from DNA to remove [[introns]] or to use alternative splicing to create a different gene product.

The primary role of mRNA in is to transfer a copy of the information coded in DNA to a [[ribosome]] to be expressed as a protein, using a form of RNA known as messenger RNA ([[mRNA]]).  mRNA in eukaryotes undergoes spicing after transcription from DNA to remove [[introns]] or to use alternative splicing to create a different gene product. Alternatively-spliced transcripts can also express the same protein, but at different levels, due to the removal or addition of regulatory sequecnces.

The main role of [[tRNA]], or transfer RNA is to carry an amino acid to the mRNA (while the mRNA is in the ribosome) during translation of the mRNA into a protein.

The main role of [[tRNA]], or transfer RNA is to carry an amino acid to the mRNA (while the mRNA is in the ribosome) during translation of the mRNA into a protein.

Purification of RNA is problematic as enzymes that degrade RNA ([[RNases]]) are ubiquitous.  Successful RNA purification depends on degradation of the DNA template used via DNase and avoidance of RNase using sterile technique.

Purification of RNA is problematic as enzymes that degrade RNA ([[RNases]]) are ubiquitous.  Successful RNA purification depends on degradation of the DNA template used via DNase and avoidance of RNase using sterile technique.

The polio virus is an example of an organism which contains only RNA to carry its genetic information.

The polio virus is an example of an organism which contains only RNA to carry its genetic information. Some [[protists]] such as ''Paramecium'' carry similar RNA genes in structures called micronuclei. These are involved in mating and replicate independently from the main cell nucleus.

==Prebiotic RNA Polymerization==

==Prebiotic RNA Polymerization==