0.1 Basic principles of genetics  (Page 4/19)

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.

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:

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