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There are now two DNA molecules. Each consists of an original nucleotide strand next to a new complementary strand. The two molecules are identical to each other.

A detailed and clear schematic of DNA synthesis kindly provided by Prof. Douglas J. Burks is shown below:

http://upload.wikimedia.org/wikipedia/commons/thumb/9/9f/DNA_replication.svg/691px-DNA_replication.svg.png

Lecture 5. language of genes is simple and informative

Genetic information likes a language. We use letters of the alphabet to make words and then join these words together to make sentences, paragraphs and books. In the case of DNA :

  • The alphabet is only 4 letters (A,T,G and C) long.
  • Each letter represents a chemical compound called a base or nucleotide .
  • These 4 letters are used to form the genetic words called codons .
  • Unlike a normal language, all genetic words are only three letters long.
  • These words combine together to form sentences called genes , which encode the instruction for amino acids in a polypeptide.
  • At the end of each sentence is a special word or full stop called a stop codon .
  • All the sentences join together to form a book that contains all the genetic information about you called your genome .

Let’s make some comparisons between English Language and Genetic Language:

English Language FIXME: A LIST CAN NOT BE A TABLE ENTRY.We use 26 letters to make words. The words can be any length we need. We join words together to create sentences Each sentence starts with a capital letter.Each sentence ends with a fullstop .All the sentences combine to form a book . Genetic Language FIXME: A LIST CAN NOT BE A TABLE ENTRY.DNA uses 4 molecules to make codons. The codons can only be 3 nucleotides long. The codons join together to form genes . The gene starts with codon AUG.The gene stops at a specific stop codon . All the genes combine to form the genome .

The Genetic Language of DNA provides the information needed to produce proteins . It is these proteins that carry out the biochemical processes (metabolism) to ensure an organism's ongoing survival. Proteins have their own language that has an "alphabet" of 20 "letters". These letters are the amino acids . RNA is used to "translate" genetic language into protein language. It takes the information from a gene of the DNA strand and creates the proteins necessary for life.

Along the gene (and DNA itself) the information for the amino acids that will make up the gene is stored in three-letter words called codons . Each codon specifies a particular amino acid. By "reading" this set of codons, the specific protein can be generated from this chunk of genetic code. The codons on DNA code for a specific amino acid . There are 20 amino acids commonly found in natural proteins .

Below is a “paragraph” of gene language:

CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG ACG TCC GAA GAG TGA CCG

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Source:  OpenStax, Genetics. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10782/1.1
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