Ribosome: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
A ribosome is the particle upon which [[ | A ribosome is the particle upon which [[MRNA|mRNA]] from [[DNA|DNA]] [[Transcription|transcription]] is translated to a [[Polypeptide|polypeptide]] with a specific [[amino acid|amino acid]] sequence defined by the genetic code. It is comprised of 2 subunits: | ||
30S unit: This is the smaller unit which consists of 21 proteins and a 16S RNA molecule | 30S unit: This is the smaller unit which consists of 21 [[proteins|proteins]] and a [[16S RNA molecule|16S RNA molecule]] | ||
50S unit: This is the larger unit which consists of 34 proteins and 2 RNA molecules, 23S and 5S<ref>Berg JM, Tymoczko JL, Stryer L: Biochemistry 6th (2007), WH Freeman and Company, New York. Pg 866</ref> | 50S unit: This is the larger unit which consists of 34 [[proteins|proteins]] and 2 RNA molecules, 23S and 5S <ref>Berg JM, Tymoczko JL, Stryer L: Biochemistry 6th (2007), WH Freeman and Company, New York. Pg 866</ref> | ||
The 2 units together form the complete ribosome, known as the 70S unit. S refers to the Svedberg unit, which is a measure of rate at which a compound moves when centrifuged. It is used as a measure of size of a molecule but is not directly proportional to molecular weight | The 2 units together form the complete ribosome, known as the 70S unit. S refers to the [[Svedberg unit|Svedberg unit]], which is a measure of rate at which a compound moves when centrifuged. It is used as a measure of size of a molecule but is not directly proportional to molecular weight <ref>Berg JM, Tymoczko JL, Stryer L: Biochemistry 6th (2007), WH Freeman and Company, New York. Pg 76</ref>. | ||
As ribosomes contain RNA (also referred to as ribosomal RNA-rRNA) and proteins, they are also referred to as ribonucleoproteins. Ribosomes translate mRNA in triplets (codons) by alligning complementary triplets found in tRNA molecules (anticodons). Each tRNA is assigned a specific anticodon and amino acid and therefore translation leads to the formation of a protein by forming peptide bonds between adjacently aligned amino acids | As ribosomes contain [[RNA|RNA]] (also referred to as [[rRNA|ribosomal RNA]]-[[rRNA|rRNA]]) and [[Proteins|proteins]], they are also referred to as [[Ribonucleoproteins|ribonucleoproteins]]. Ribosomes translate [[mRNA|mRNA]] in triplets ([[Codon|codons]]) by alligning complementary triplets found in [[tRNA|tRNA]] molecules ([[Anticodons|anticodons]]). Each [[tRNA|tRNA]] is assigned a specific anticodon and [[amino acid|amino acid]] and therefore translation leads to the formation of a [[protein|protein]] by forming [[Peptide bonds|peptide bonds]] between adjacently aligned [[amino acids|amino acids]] <ref>Berg JM, Tymoczko JL, Stryer L: Biochemistry 6th (2007), WH Freeman and Company, New York. Pg 872</ref>. | ||
=== References === | === References === | ||
<references /> | <references /> | ||
Revision as of 20:37, 29 November 2010
A ribosome is the particle upon which mRNA from DNA transcription is translated to a polypeptide with a specific amino acid sequence defined by the genetic code. It is comprised of 2 subunits:
30S unit: This is the smaller unit which consists of 21 proteins and a 16S RNA molecule
50S unit: This is the larger unit which consists of 34 proteins and 2 RNA molecules, 23S and 5S [1]
The 2 units together form the complete ribosome, known as the 70S unit. S refers to the Svedberg unit, which is a measure of rate at which a compound moves when centrifuged. It is used as a measure of size of a molecule but is not directly proportional to molecular weight [2].
As ribosomes contain RNA (also referred to as ribosomal RNA-rRNA) and proteins, they are also referred to as ribonucleoproteins. Ribosomes translate mRNA in triplets (codons) by alligning complementary triplets found in tRNA molecules (anticodons). Each tRNA is assigned a specific anticodon and amino acid and therefore translation leads to the formation of a protein by forming peptide bonds between adjacently aligned amino acids [3].